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Effect of Long Term Use of Bovine Somatotropic Hormone on Milk production, Reproduction, Nutrient Utilization and Blood
metabolites in Nili-Ravi Buffaloes
BY
IFTIKHAR AHMAD
2004-VA-01
A thesis submitted in partial fulfillment of requirements for degree of Doctor of Philosophy in Animal Nutrition
UNIVERSITY OF VETERINARY AND ANIMAL SCIENCES, LAHORE
2009
II
III
IV
Effect of Long Term Use of Bovine Somatotropic Hormone on milk Production, Reproduction, Nutrient Utilization and Blood
metabolites in Nili-Ravi Buffaloes
BY
IFTIKHAR AHMAD 2004-VA-01
A thesis submitted in partial fulfillment of requirements for degree of
Doctor of Philosophy in Animal Nutrition
UNIVERSITY OF VETERINARY AND ANIMAL SCIENCES, LAHORE
2009
V
To
The Controller of Examinations
University of Veterinary and Animal Sciences,
Lahore.
We the members of supervisory committee certify that the contents and form of the
thesis submitted by Mr. Iftikhar Ahmad has been found satisfactory and recommend that it
be processed for evaluation by external examiner (s) for the award of degree.
CHAIRMAN -----------------------
MEMBER---------------------------
MEMBER---------------------------
VI
ACKNOWLEDGEMENT
O ver above every th ing I offer m y hum ble and sincerest gratitude to A L M G H T Y A L M G H T Y A L M G H T Y A L M G H T Y
A L L A H ,A L L A H ,A L L A H ,A L L A H , the m ost M ercifu l and Com passionate, the m ost G racious and B eneficent, W ho
bestow ed on the deep oceans of know ledge already existing. I offer m y hum blest thanks; form the
deepest of m y heart to the H oly Prophet, M U H A M M A DH oly Prophet, M U H A M M A DH oly Prophet, M U H A M M A DH oly Prophet, M U H A M M A D (peace be upon h im ) w ho is, forever a
torch of gu idance and know ledge for hum anity as a w hole.
This m anuscript w ould not have been possible w ithout the enthusiasm , know ledge,
gu idance, tenacity, and, perhaps m ost im portantly faith that I received from m y supervisor,
P rofessor D r. M akhdoom A bdul Jbbar, Chairm an, F ood and N utrition D epartm ent, P rofessor D r. M akhdoom A bdul Jbbar, Chairm an, F ood and N utrition D epartm ent, P rofessor D r. M akhdoom A bdul Jbbar, Chairm an, F ood and N utrition D epartm ent, P rofessor D r. M akhdoom A bdul Jbbar, Chairm an, F ood and N utrition D epartm ent, F rom the
very first interv iew to the last queries on research accom plishm ents and career p lans, he w as
alw ays eager to entertain m y ideas in hope that I fulfilled m y dream (s) and becom e successfu l. I
w as not sure I could handle an undertaking of such a m agnitude, but w as able to thanks to h is
consistent effort and true desire to keep m e on track .
I am greatly indebted to, P rofessor D r. T alat N aseer P asha D ean F aculty of A nim al P rofessor D r. T alat N aseer P asha D ean F aculty of A nim al P rofessor D r. T alat N aseer P asha D ean F aculty of A nim al P rofessor D r. T alat N aseer P asha D ean F aculty of A nim al
production and Technologyproduction and Technologyproduction and Technologyproduction and Technology and P rofessor D r. M uham m ad A bdullah D epartm ent of L ivestock P rofessor D r. M uham m ad A bdullah D epartm ent of L ivestock P rofessor D r. M uham m ad A bdullah D epartm ent of L ivestock P rofessor D r. M uham m ad A bdullah D epartm ent of L ivestock
P roductionP roductionP roductionP roduction for their great help painstaking contribution during the course of research and
finalization of th is w rite up .
I ow e a debt of gratitude to D r. R ashid A hm ad, D irectorD r. R ashid A hm ad, D irectorD r. R ashid A hm ad, D irectorD r. R ashid A hm ad, D irector L ivestock Production R esearch
Institute, B ahadurnagar, O kara and R aja M uham m ad L atifeR aja M uham m ad L atifeR aja M uham m ad L atifeR aja M uham m ad L atife, Sen ior R esearch O fficer, A nim al
N utrition Center, R akh D era Chahal, L ahore for their generous co- operation , help and provid ing
an environm ent conducive for a creative activ ity like research .
I am also thankful to D r. K halid JavidD r. K halid JavidD r. K halid JavidD r. K halid Javid , A ssociate Professor D epartm ent of A nim al
B reeding and G enetics for h is help during the w rite up phase. I feel p leasure to p lace on record m y
profound obligation to D r. Sualeha R affitD r. Sualeha R affitD r. Sualeha R affitD r. Sualeha R affit, A ssistant Professor, D epartm ent of Pharm acology,
U niversity of V eterinary and A nim al Sciences, L ahore for her active cooperation during m y Ph.D .
studies.
VII
L ast but not the least, I am greatly indebted to m y brothers, for their love, im m ense
orison , w hich heartened m e to achieve success in every sphere of life and w hose hands alw ays
rem ained raised in prayer for m e.
(IF T IK H A R A H M A D )(IF T IK H A R A H M A D )(IF T IK H A R A H M A D )(IF T IK H A R A H M A D )
VIII
CONTENTS
CHAPTERS T I T L E Page
List of tables IX
List of figures XI
1 Introduction 1
2 Review of literature 6
3
Effect of long-term use of bovine somatotropic hormone on
milk production, Reproduction and physiological parameters in
Nili Ravi Buffaloes
Abstract
Introduction
Materials and Methods
Results and discussion
31
31
32
33
40
4
Production Performance of Lactating Nili-Ravi Buffaloes
under the influence of Somatotropic Hormone on varying
levels of dietary Energy
Abstract
Introduction
Materials and Methods
Results and discussion
64
64
65
66
70
5
Publications
I Effect of bovine somatotropic hormone on the
productive Performance of Nili-Ravi buffaloes
II Performance of lactating buffaloes administered bovine
somatotropin hormone
76
81
6 Summary 84
Literature cited 88
IX
LIST OF TABLES Table No
T I T L E
Page
1 Average chemical composition of fodders (self analyzed in
nutrition labs. at University of Veterinary and Animal Sciences,
Lahore) used to fulfill the maintenance requirements of
experimental animals during study period.
36
2 Composition of Concentrate Ration used to fulfill the production
requirements of treated (+bST) and control (without bST) during
study.
37
3 Effect of bovine somatotropic hormone administration on Milk
yield of Nili- Ravi buffaloes (means ± SE)
45
4 Effect of recombinant bovine somatotropic hormone on
productive traits of Nili- Ravi Buffaloes (means ± SE).
47
5 Effect of bovine somatotropic hormone administration on milk
components of lactating Nili –Ravi buffaloes over the 3 year
study period
50
6 Effect of bovine somatotropic hormone administration on
reproductive parameters of lactating Nili –Ravi buffaloes during
study period.
54
7 Effect of bovine somatotropic hormone administration on health of lactating Nili- Ravi buffaloes
57
X
8 Effect of bovine somatotropic hormone administration on
hematology of lactating Nili –Ravi buffaloes (Means ±SE)
58
9 Administration effect of bovine somatotropic hormone on blood
metabolites in lactating Nili –Ravi buffaloes (Means ±SE).
60
10 Effect of bovine somatotropic hormone administration on mineral
metabolites of lactating Nili –Ravi buffaloes (Means ±SE)
61
11 Economics of use of bovine somatropic hormone in lactating Nili-
Ravi buffaloes.
63
12
Ingredients and Chemical Composition of Total Mixed Rations
(TMR) offered with administration of bST in Nili Ravi buffaloes.
67
13
Effect of bovine somatotropic hormone administration on
productive performance with in lactating Nili Ravi buffaloes fed
varying level of dietary energy (means± SE).
72
14 Effect bovine somatotropic hormone adminstration on daily nutrients intake of in Nili Ravi buffaloes fed varying level of dietary energy (means± SES).
75
15 Mean (± S.E.) values of different haematological and biochemical
parameters.
79
16 Intake and digestibility of nutrients in buffaloes administered
Bovine somatotropin hormone.
81
17 Performance of buffaloes on bST administration.
82
XI
LIST OF FIGURES
S.No T I T L E Page
1 Monsanto mechanism of recombinant bovine somatotropic
hormone
8
1 Trend of milk production in control and bST- treated groups
during the first year of the study
43
2 Milk production pattern in control and bST- treated groups
during the 2nd year of the study.
44
3 Trend of milk production in the control and bST-treated
groups during the 3rd year of the study.
44
4 Comparison of milk production in control and bST-treated
groups over the 3 year study period.
45
5 Comparison of lactation length (LP), dry period (DP) and
calving interval (CI) in bST-treated and control groups during
the study period
48
6 Comparison of yearly and overall milk fat % of bST-treated
and control groups over the study period
51
7 Comparison of yearly and overall solid not fat % of bST-treated
and control groups during the study period.
51
8 Comparison of year wise and overall total solids % of bST-
treated and control groups during the study period.
52
9 Comparison of reproduction parameters (post partum estrus
[PPE], service period [SP]) of bST-treated and control groups
during the study period.
55
10 Trend of milk production in animals given low, medium and
high-energy diets.
71
11 Average feed efficiency of bST-treated Nili-Ravi buffaloes fed
low, medium and high energy density rations
74
1
Chapter-1
INTRODUCTION
Adaptation of recent developments in various scientif ic and
technological f ields is important to sustain the growing world
population, which is predictable to reach 8000 million by 2020, of
which about 6700 mill ions will be in developing countries (Mehra,
2001). It has been estimated that the supply of food required to
adequately meet human nutritional needs over the next 40 years is
quantitatively equal to the amount of food previously produced
throughout the history of mankind (NRC, 1994). With f inite resources
and an increasingly vulnerable environment, i t is highly important that
eff icient growth of agriculture and livestock products should be a
dominant factor. To meet future needs and to sustain agricultural
production, agricultural research and its applications wil l have to use
all available technologies and especially the rapidly developing modern
biotechnologies that increase productive eff iciency of food production.
With respect to animal production, synthetic bovine somatotropic
hormone (bST) is one of biotechnological product that increases the
food production per unit of feed intake (Bauman, 1992).
Bovine somatotropic hormone is produced by the somatotrophs of
the anterior pituitary gland and consists of a chain of 190 to 191 amino
acids (Hedge et al. , 1987). The secretion of bovine somatotropic
hormone is regulated by two well-known hypothalamic peptides that
proceed to motivate (growth hormone-releasing factor) or diminish
(somatostatin) the release of ST from the pituitary gland (Tuggle and
Trenkle, 1996). The amino acid sequence of bST is substantially
2
different from human ST (35% of the amino acids in hST vary from
bST). For this difference, bST has no effect on human development, in
harmony with their binding aff inity to the hST receptor being several
orders of magnitude lower than that of hST (Lesniak et al., 1977).
Bovine somatotropic hormone is released from the pituitary as
four variants. These variants have either a leucine or valine substitution
at posit ion 127 and an alanine or a phenylalanine at the NH2 terminus
(Wood et al., 1989). The variation in the NH2 terminus is due to
differences in cleavage of the signal peptide. The frequency of these
gene alleles differs between dairy breeds (Lucy et al., 1993).
Furthermore, there are some signs that these variants may differ in their
effectiveness. Although studies have been limited, results indicate that
treatment with the valine-127 variant elicited a greater increase in
circulating ST and milk yield than the leucine-127 variant (Eppard et
al. , 1992). The commercial bST formulation (Monsanto, St. Louis, MO)
approved for apply in dairy cows is leucine variant-127, it has an extra
methionine at the NH2 terminus.
Somatotropic hormone was first characterized in the 1920s when
Evans and Simpson demonstrated growth-promoting effects in rats
treated with a crude extract from bovine pituitaries. The discovery that
the pituitary contained a factor that stimulated growth led to this factor
being referred to as "growth hormone." It became apparent shortly
thereafter, however, that growth hormone did much more than
stimulating growth, since administration of pituitary extracts also
enhanced milk yield in lactating goats (Asdell, 1932). Major research
development in ST study was accomplished in 1937, when Russian
scientists treated dairy cows with BST and demonstrated that milk yield
was increased with the administration of pituitary extract (Asimov and
3
Krouze, 1937). Studies conducted in the 1940s showed that BST
augmented the milk yield of dairy cows; however, the amount of BST
that could be extracted from the pituitary glands of slaughtered animals
was inadequate to impact commercial production (Young, 1947). In
1982, bST was produced by DNA biotechnology that permitted
scientists around the world to observe various aspects of its biology
(Bauman, 1992).
The dependable genes for production of BST in catt le were
identif ied in bovine t issue cells, which cause the pituitary cells to
produce the biological product of BST. These genes were isolated and
inserted into specif ic bacteria as a part of plasmid, as these altered
bacteria replicate, the new genes are also replicated and conceded along
to all new bacteria. The presence of these genes causes the bacterial
cell to become a lit t le manufacturing plant, which produces bST in
large quantities. Eventually the bacterial cells are kil led and removed,
leaving the purif ied bST (Bauman et al., 1985; Roush, 1991).
Somatotropic hormone orchestrates many diverse physiological
processes, so that for milk synthesis (during lactation) additional
nutrients can be uti l ized. Somatotropic hormone is a homeorhetic
control that affects numerous target tissues in ways that are highly
coordinated to affect marked changes in nutrient partitioning among
these tissues. The biological effects of somatotropic hormone can be
broadly classif ied as either somatogenic or metabolic. The somatogenic
effects are those in which ST stimulates cell proliferation. These effects
are mediated by insulin-l ike growth factor (IGF-I) (Rechler and
Nissley, 1990).
Milk yield response to bST has been observed for all dairy breeds
and in animals of different parity and genetic potential (Burton et al. ,
4
1994). In general, milk yield response in early lactation is very small,
and thus bST use is usually over the last 80% of the lactation cycle.
Typical milk yield responses are increases of 10-15% although even
greater increases occur when the management and care of the animals
are excellent (Chil l iard, 1989; NRC, 1994).
Bovine somatotropic hormones improve the productive eff iciency
because administration of bST to dairy animals increases milk yield per
unit of feed. In dairy cattle, use of bST has resulted in improvements
of 12-25% in milk yield without any substantial alteration in the
composition of milk (Ludri et al., 1989). BST hormone reduces the
proportion of maintenance requirement out of total nutrient intake
(Bauman et al., 1989). The higher productive response is attributed to
changes in coordinated metabolism of various body organs and tissues
that support increased synthesis of lactose, fat and protein in mammary
glands, in meticulous the glucose and fatty acid metabolism that
account for increase in lactose and milk fat using bST treatment
(Bauman et al., 1988). An addit ional beneficial effect is improvement
in pregnancy rates when bST is injected during the period prior to
estrus and subsequent artif icial insemination (Santos et al. , 2004).
Most of available studies on bST hormone are related to cattle,
however, buffalo is the main dairy animal in Asia and 97% of the world
population is found in Asian subcontinent (FAO, 2004). Of the total
worldwide milk production 12.84% comes from buffalo, with 97.11% of
buffalo milk produced in the developing countries of Asia. Over the
last decade the annual growth in buffalo milk production was 6.19%
higher than that of worldwide total milk production (FAO, 2003),
highlighting the importance of buffalo as a dairy animal. In spite of
large numbers and good adaptabil ity, per animal productivity is very
5
low as compared to Western dairy animals. The normal lactation yield
in the best-known dairy breeds eg. Nil i-Ravi and Murrah is around
2000 kg (Agarwal and Tomar, 1998).
There are multiple approaches to improve productivity of the
dairy buffalo including improvement in genetics, nutrition and
management. Use of bST is one way for increasing milk production in
dairy animals. Usmani et al. (1991) have suggested that research should
be planned to determine the effect of bST in buffaloes before its
commercialization in Pakistan. However, since then some researchers
have undertaken short-term studies involving buffaloes but
comprehensive information is stil l lacking. The present project was
planned to ascertain the consequences of extensive use of bST on
productive and reproductive parameters in lactating Nili-Ravi buffaloes
with the following objectives
a) To study the long term effect of bST hormone on production,
reproduction and physiological parameters in Nil i-Ravi buffaloes.
b) To monitor the quality of milk under the influence of bST through
chemical composition.
c) To study the effect of bST on nutrient uti l ization in Nili- Ravi
buffaloes.
d) To determine the optimum dietary energy levels for eff icient milk
production using bST in Nil i-Ravi buffaloes.
6
Chapter-2
REVIEW OF LITERATURE
2.1 Bovine somatotropic hormone
The effects of somatotropic hormone on the performance of
animals have been the subject to interest for over 50 years. Early
research established that injection of crude pituitary extracts increased
growth rate in rats. This extract was called somatotropin, a Greek word
meaning “tissue growth”. Somatotropin is a hormone that is produced
by one organ and transported to another to cause a biological effect. In
contrast to steroid hormone it is composed of 20 different amino acids,
which are combined in specif ic sequence to form different body
proteins, however, every species has its own amino acid sequence
(Kostyo and Reagan, 1976 ). Being a proteinous hormone in nature it
must be injected for biological activity and if it is given orally the
hormone is broken down in to amino acids during the digestive process
like other dietary proteins (Juskevich and Guyer, 1990). In order to
produce biological effect, protein hormone must f irst bind to specif ic
receptors located at the cell surface. The amino acid sequence develops
its three dimensional shape, which determines whether the protein wil l
be able to bind to t issue and elicit a biological response. On the
identif ication of the amino acid sequence it becomes clear that the three
dimensional unique shape of bovine somatotropic hormone (BST)
differs from that of human somatotopin (hST). This means that it is not
possible to bind BST receptors to human tissues (Wallis, 1975).
However, BST is biologically active in sheep because the amino acid
composition of ovine somatropin and BST differ only by one amino
acid. BST, which is naturally produced in cows, has homeorhetic
7
control that coordinates the metabolism of many tissues in dairy cattle
(Bauman et al., 1988).
2.2 Recombinant bovine somatotropic hormone (bST)
Prior to 1980s restricted progress was made in BST research
due to limited availabil ity and its high cost of production because it
was extracted in only small quantities with varying purity from each
pituitary gland of slaughtered animals. Thus only a limited number
of dairy animals were able to be treated for only a l imited period of
time (Peel and Bauman, 1987). The advent of recombinant DNA
technology allowed the production of large quantit ies of synthetic
bST. Since then a lot of research has been conducted on the effect of
bST on different production parameters (Peel et al. , 1985; McGuffy
et al. , 1990). Bauman et al. (1982) were the foremost researchers
who util ized the recombinant methionyl bovine somatotropic
hormone and showed that i t was effective as a pituitary derived
growth hormone in enhancing the milk production. Recombinant
bovine somatotropic hormone (bST) is a genetically engineered
synthetic analogue of the natural hormone. Scientists identif ied the
gene responsible for the production of natural BST and by using
standard genetic–engineering techniques (Fig 1), duplicated the gene
and spliced it into the DNA of Escherichia coli (E. coli) bacterium.
These bacteria can be grown in fermentation tanks and bST is
produced with the organism. The E. coli are killed and ruptured and
large amounts of bST can then be inexpensively extracted for
injection into the cow (Bauman et al., 1985; Roush, 1991). The
injection of bST produces a biological reaction that is essentially the
same as that which occurs in dairy cows that naturally produce
higher levels of BST (Bauman et al. , 1985).
8
Figure I. Monsanto mechanism for the production of recombinant
bovine somatotropic hormone (www.diseaseproof.com)
9
2.3 Mechanism of action of bST
Somatotropic hormone, through homeorhetic control, shifts the
partitioning of nutrients in a lactating cow so that more nutrients are
used for milk synthesis (Bauman, 1992). This involves coordinating the
metabolism of diverse body organs and tissues and includes the
metabolism of al l nutrients (carbohydrates, lipids, proteins and
minerals). Thus, treatment with bST not only increases the rate of milk
synthesis within the mammary gland but also orchestrates other body
processes in a manner to provide the necessary nutrients to prop up this
enhanced rate of milk synthesis. Baldwin and Knapp (1993)
summarized a number of the major coordinated changes that occur with
bST treatment of a dairy cow. These adaptations are of critical
importance during the init ial period of bST treatment when milk
production is augmented but feed intake is not affected. These
adaptations can be broadly divided into two types (i) direct effects on
some tissues; and (i i) indirect effects that are thought to be mediated by
the insulin-l ike growth factor (IGF) system (Bauman and Vernon,
1993).
Direct actions of ST appear to be primarily concerned with the
coordination of metabolic processes (Bauman, 1992; Baldwin and
Knapp, 1993). Adipose tissue provides an example to demonstrate the
mechanisms of action. Adipose tissue has two main functions,
lipogenesis and lipolysis. Somatotropic hormone treatment has no acute
effects on either of these functions, but it does alter l ipid metabolism
on a chronic basis. In particular, ST treatment changes adipose tissue
retort to homeostatic signals affecting lipid synthesis and l ipid
mobil ization. Studies have shown that somatotropic hormone reduces
10
the abil ity of insulin to stimulate lipid synthesis and enhances the
abili ty of catecholamine to stimulate l ipolysis. Thus, if the cow is in a
posit ive energy balance, bST treatment reduces the nutrients used for
body fat and these nutrients are redirected in support of the increased
milk synthesis (Bauman and Vernon, 1993). On the other hand, if the
cow is near zero or in negative energy balance when bST treatment is
initiated, then body fat reserves are mobil ized to support the need of
nutrients for the additional milk production. With prolonged
Somatotropic hormone treatment, voluntary food intake increases and
animals return to a positive energy balance allowing the replenishment
of body reserves over the lactation cycle (Bauman et al ., 1988)
The indirect effects of ST appear to be primarily associated with
the mammary gland through the actions of IGF system (Bauman and
Vernon, 1993). These effects involve an increase in the rate of milk
synthesis per cell and an improved maintenance of mammary cells. The
IGF system is complex involving IGF-1 and IGF-1I as well as two
specif ic IGF receptor types (Celemmons and Underwood, 1991). In
addit ion, the preponderance of IGFs in body f luids is bound to soluble,
high aff inity binding proteins. There are six specif ic IGF-binding
proteins (IGFBP) and their postulated roles include serving as
circulatory transport vehicles, retarding IGF degradation, facilitating
transvascular movement, providing an extra vascular pool, and
modulating directly the actions of IGFs at specif ic marked cells.
Administration of bST to well-managed lactating cows causes an
increase in circulating concentrations of IGF-1 and IGFBP-3 and a
decrease in IGFBP-2 (Bauman and Vernon, 1993).
11
2.4 Milk production and bST
Administration of bST has been reported to enhance the lactation
performance in all dairy breeds but milk yield response to bST is
dependent on the dosage level, parity and genetic potential of the
animal (Burton et al. , 1994). It must be given each day to maintain an
increased milk response because it is not stored in the body and is
rapidly cleared from the blood stream. To amplify milk yield bST must
be administered daily or in prolonged release formulation. Ludri and
Singh, (1989) reported increased milk yield over controls by 19.4 and
32.39% for 25 and 50 mg bST/d, respectively in Murrah buffaloes. In
dairy cows increases in milk production with similar protocols ranged
from 15 to 25%. Similarly, Chil l irad (1989) summarized the conclusion
of different studies and reported that daily milk yield increased 2.8,
3.9, 5.2 and 5.6 kg/d against 5, 10, 20 and 31 mg bST/d, respectively.
In the same way super-physiological doses of Sometribove have been
shown to increase milk production. Eppard et al. (1991) evaluated the
effect of bST in a sustained-release formulation administered to
lactating cows at concentrations up to 3.0 g every 14 d over two
lactations. During the f irst and 2nd year of treatment, administration of
bST increased mean 3.5% fat-correct milk (FCM) by 21.1 and 24.8 kg/d
respectively over the control.
Other researchers have also reported increased milk yield in
response to bST administration. Phipps et al. (1997) investigated the
effects of administration of a prolonged-release formulation of bST at
14 d intervals on milk production of indigenous, crossbred, and
purebred cows in Africa. Administration of 334 mg bST increased milk
from 22 to 25% in various breeds of cattle; however, increasing the
12
dose by 500 mg did not further increase milk production. To determine
the breed difference in milk yield response to bST, Jorge et al. (2002)
studied the effect of administering 500 mg bST every 14 d for a period
of seven months on milk production of Murrah buffaloes and found that
milk production was increased in the treated group by 15.72% on total
milk yield, adjusted 4% of fat corrected milk (FCM). Similarly, Mishra
and Shukla (2004) investigated the effect of bST on milk yield with
normal recommended dose of 250mg/14 d in lactating buffaloes and
found a 25% increment in milk yield.
The milk yield response to bST is generally dose dependent and
related to lactation period. Mc Guffy et al. (1991) evaluated lactation
performance of multiparous Holsteins cows supplemented with 0, 320,
640, or 960 mg of Sometribove every 28 d. The treatment period was of
various lengths, depending upon stage of lactation of animals at f irst
administration (of bST). Milk and 3.5% FCM yields were increased by
each dose of Sometribove in all stages.
Whilst administering bST increases milk production in the current
lactation, the effects of long-term administration of bST are less clear.
Hansen et al. (1994) conducted a long-term study to observe the effects
of bST in herds of Holstein cows. bST was injected daily from 28 to 35
d postpartum with 0 (control), 5.15, 10.3, and 16.5 mg bST/d for a two-
year period. During the f irst year FCM production increased l inearly in
response to increased bST administration; however, the magnitude of
this increase decreased in the second year to only 67% of the response
during the f irst year.
Posit ive responses to bST have been reported during short term
studies for other species. Baldi (1999) reported increased milk yield
13
(20-30%) in dairy ewes following treatment with bST. Similarly in
dairy goats, administration of bST increased overall milk yield by 14-
29%. In Ital ian river buffalo bST treatment increased milk yield by
about 17%. In general, studies on dairy ruminants show that treatment
with bST increased milk production in the short term (immediate post
injection period) and that there is also a medium to long term effect on
persistency of lactation (Huber et al. , 1997).
Use of bST during the transit ion period may cause positive and
beneficial effects supporting milk synthesis prior to parturition. Milk
production response to bST occurs because of its known effects on
partitioning of nutrients and because a greater proportion of the
nutrient intake is used for milk synthesis. It increases liver glucose
output, cardiac output, blood f low to the mammary gland and uptake of
nutrients used for milk synthesis by the mammary gland among other
effects. In addit ion, ST decreases the rate of oxidation of amino acid
and glucose and therefore decreases glucose clearance (Gulay and
Hatpolu, 2005). Treatment with bST results in coordinated changes of
various organs and tissues that naturally occur during the transit ion
from a non-lactating to lactating state when circulating concentration of
ST is high. Gulay et al. (2004) investigated the effect of low doses of
bST during the transition period and early lactation period and their
results suggested that administration of low dosage of bST during the
transit ion and early lactation period resulted in increases in milk yield.
In early lactation there is typically an extensive period of
negative energy balance. There are signif icant responses in milk yield
to bST administration, especially when used in combination with
feeding of high energy density rations Polidori et al . (1997) evaluated
14
the effects of bST and calcium salts of long chain fatty acids during
early lactation of Italian river buffaloes and found that bST along with
high energy diets had a beneficial effect on milk yield. Moalllem et al .
(2000) allocated high yielding, individually fed cows to three
treatments or a control group. Calcium soap of fatty acids was fed at
2.2% DM, and bST injected from 10 - 150 days-in-milk (DIM). They
found that treating high yielding cows with bST in early lactation
increased milk production at the expense of an extensive period of
negative energy balance. However, Vicini et al. (1994), in investigating
the effect of supplemental energy and protein on milk production
response to bST in cows found that additional energy and protein did
not alter the milk production response to bST. Similarly, Bremmer et
al. (1996) found that additional ruminally-protected amino acids and fat
in combination with bST resulted in no response in milk production in
cows fed a well balanced diet.
Several researchers have investigated the effects of bST when
used in combination with dietary treatments. Nisa et al. (2006)
investigated the effect of bST when used in combination with varying
levels of enzose on milk yield and its composit ion in lactating Nili-
Ravi buffaloes. They found the interactions for bST x Enzose were
signif icant only for milk yield and milk ash contents (P<0.025), with
bST administration increasing milk production by 30% when used in
combination with 20% enzose. Abo El-Nor et al. (2007) evaluated the
effects of bST and monensin on the milk yield in buffaloes. The control
group of animals was fed a basic ration, the 2nd group was also fed the
basic ration and injected with bST, the 3rd group was fed the basic
ration and supplemented with 4 g monensin/hd/d whilst the 4th group
was fed a supplemented ration as well as being administered bST.
15
Animals treated with bST had signif icantly higher milk yield (p<0.01),
and this was attributed to increased production of propionate in the
rumen. Monensin treatment caused increased production of insulin by
the pancreas, resulting in a decreasing effect on the production of
somatotropin and thus diverting nutrients to body tissues rather than to
milk production. Khattab et al. (2008) evaluated the singular and
combined effect of bST and monensin on the productive performance of
buffaloes. They found that treatment with bST resulted in signif icant
production benefits including higher milk yield and 4% FCM yield and
importantly, without any adverse effects on the health of lactating
buffaloes.
Management and nutrit ion are major factors that affect responses
in lactation yield and its persistency to bST administration. A poorly
managed herd is l ikely to achieve li t tle or no benefit f rom bST use
(Bauman, 1989). Mollet et al. (1986) reported that deficiencies in
environmental, nutrit ional and milking management programs may
attributed to the lack of response to bST. In investigating the
interaction of the effects of photoperiod and bST on milk production
Miller et al. (1999) found that a combination of bST with long daily
photoperiod tended to amplify the increases in milk production. Van
Baale et al. (2005) determined the effects of bST on early lactation
milk yield and subsequent lactation persistency with or without bST
Treatments included a control group milked 3x and three groups milked
6x for either the f irst 7, 14, or 21 DIM. These four groups of cows all
received bST starting at 63 DIM. The fif th treatment group was also
milked 6x for the f irst 21 DIM but these cows received no bST during
the entire lactation. Cows subsequently administered bST (at 63 DIM)
16
produced more milk (38.8 vs. 34.2 ± 0.9 kg/d) than the group injected
in early lactation.
2.5 Milk composition and bST
Like milk yield, bST may also affect milk composit ion, but
mostly the effect is only minor. Bauman et al. (1989) evaluated the
eff icacy of a prolonged-release formulation for sometribove (n-
methionyl bST) in Holstein cows. Milk contents of lactose, fat, ash,
and calcium were not affected in primiparous and multiparous animals
but protein and phosphorous were slightly greater (less than 5%) in
milk from sometribove-treated cows. In contrast, Barbano et al. (1992)
found variable effect of bST on milk composit ion. The
concentrations of milk lactose, fat and ash were similar from cows
receiving bST or excipient; however, percentages of non-protein
nitrogen (NPN) and total protein were greater in milk from bST-treated
cows compared with milk from cows injected with excipient. Lynch et
al. (1992) injected Holstein cows bi-weekly (from 60 ± 3 d postpartum
and continued at 14-d intervals for the ful l lactation) and found that
whilst production of milk, total fat, and all milk fat components
measured were increased, the average fatty acid composit ion of milk fat
remained unchanged. Phospholipids and cholesterol content of milk
changed with stage of lactation but were not influenced by bST
treatment. They concluded that the composit ion of milk is more
influenced by dietary manipulation than by administration of bST.
Stegeman et al. (1992) evaluated the interactions between bST and
dietary fat supplementation (either from sunflower or saff lower seeds)
on the composition and flavor of milk and butter. Supplementation with
unsaturated dietary fat resulted in lower concentrations of short- and
17
medium-chain and higher concentrations of long-chain fatty acids in
milk fat and butter. Sensory evaluations indicated that butters from the
bST with sunflower seed and bST with saff lower seed treatments were
equal or superior in f lavor to the butter from the control cows. Milk
from cows receiving bST or supplemented with unsaturated dietary fat
and receiving bST was no more susceptible to oxidized off-f lavors than
control milk.
Responses in milk composition are often mediated by the energy
status of the cows. Capuco et al. (2001) investigated the relationship
between energy balance and effects of bovine somatotropin (bST) on
thyroid hormone metabolism and cytokine concentrations in serum.
Cows were fed to achieve either positive or negative energy balance
and then administered 40 mg bST/d. Whilst bST decreased energy
balance in both groups of animals, milk production and the fat
percentage of milk increased in response to bST treatment in both
dietary groups. Other researchers have investigated potential
relationships between bST and other hormones in the dairy animal.
Molento et al. (2002) investigated the effects of insulin, bST, and their
interaction on milk protein and selected blood parameters in Holstein
cows. Percent milk protein and urea contents were found to be lower
during bST administration, regardless of insulin infusion.
Micro-constituents of milk are also unchanged under the
influence of bST. For example, milk from bST-treated cows does not
differ in vitamin content or in concentrations of nutritionally important
mineral elements (Bauman, 1992). Long-term studies conducted at four
different locations (Missouri, New York, Maryland, and Utah)
involving a total of 364 cows indicated that the percentage of total ash,
phosphorous and calcium in milk was not altered by bST administration
(Hard et al. , 1988). Milk also contains many hormones and growth
18
factors; two that have received substantial attention are somatotropin
and insulin-like growth factor-I (IGF-I). Milk concentration of bST
only increase when provocative doses of exogenous bST are
administered to dairy cows (Burton et al. , 1994; Juskevich and Guyer,
1990). In the case of IGF-I, small increases in milk concentrations were
observed in the init ial studies. But as the number of animals and range
of situations were expanded, it became evident that milk IGF-I varied
widely between cows and was affected by many factors (stage of
lactation, environment) and that the use of bST had minimal impact on
the milk concentration of IGF-I (Juskevich and Guyer, 1990; Coll ier et
al. , 1991). Only l imited research has been conducted into the enzymes
in milk in relation to the bST administration in dairy animals. No
signif icant differences in the activit ies of aminopeptidase,
endopeptidase, phosphatase, protease, lipase (Lynch et al. , 1988) and
lipoprotein lipase (Lough et al. , 1989) in milk have been found in milk
from treated and untreated animals. The pH of the milk has also been
found to be not affected by bST injections in different studies (Baer et
al. , 1989). Overall, studies on the macro and micro components of milk
indicate that composit ion is unchanged by use of bST.
2.6 Calving interval and bST
Intercalving interval is often increased as a result of
bSTadminstration’ McGuffey et al. (1991) observed the lactation
performance of multiparous Holstein cows from five herds
supplemented with 0, 320, 640, or 960 mg of Somidobove every 28 d in
early, mid or late stages of lactation. For the early cows, days to
postpartum estrus and service period were similar, however, total
number of inseminations for cows receiving Somidobove was twofold
greater than for the control animals, resulting in a longer calving
19
interval. The duration of treatment with bST also affects intercalving
interval. Esteban et al. (1994) studied the relationship of calving
interval with conception in cows treated for two lactations with
recombinant bST. Multiparous cows treated during the f irst lactation
had signif icantly longer intervals from calving to conception. However,
cows treated during the previous lactation, but not during the second
lactation, had signif icantly shorter intervals from calving to
conception.
2.7 Reproductive performance and bST
The effects of bST on reproductive performance appear to be
variable. Judge et al. (1999) administered bST (500 mg) every 14 d
beginning at 63 d of lactation and continuing unti l 21 d prior to the end
of lactation. They found bST had no signif icant impact on reproductive
performance. Silvia et al. (2002) also found reproductive performance
to be unaffected by bST. In their study cows were randomly allocated
to receive bST supplementation at 14 d intervals, beginning during
weeks 9 to 10 and weeks 17 to 18 after calving. Administration of bST
at weeks 17 to 18 postpartum had no beneficial effect on reproductive
performance of multiparous cows. However, the length of exposure to
bST does not appear to y have an impact on reproductive performance.
Esteban et al. (1994) investigated reproductive performance in cows
exposed for two lactations to recombinant bST. During the f irst
lactation, the chances of a cow becoming pregnant decreased l inearly as
dose increased. During the second lactation, pregnancy rates were
similar to those in the f irst lactation, with again the rates reduced as
bST dose increased.
20
Whilst the hormonal induction of lactation may have an adverse
effect on milk yield in bST treated cows, it does not affect subsequent
reproductive performance of these cows. Mellado et al. (2006) util ized
high-yielding dairy cows in a large dairy operation where bST was
routinely used in all cows. The proportion of cows pregnant was similar
in induced cows and non-treated cows (71 vs. 75%). Thatcher et al.
(2006) reported that coupled with a timed-insemination program or
cows detected in estrus, administration of bST increased embryo
development and embryo survival. In contrast, Waterman et al. (1993)
suggested that chronic administration of a high dose of bST could
reduce reproduction performance by promoting ovarian acyclicity.
2.8 Conception rate and bST
Changes in conception rate in response to the administration of
bST have been variable. Luna-Dominguez et al. (2000) investigated the
effects of bST treatment on reproductive performance in two high
producing herds and found that at 180 d postpartum 65.4 vs. 48.5%
cows were pregnant in control and treated groups, respectively.
However, f irst-service and conception rate were not signif icantly
different between the groups. In contrast, Santos et al. (2004) found
that bST improved conception rates in cyclic cows. Moreira et al.
(2000) examined the effect of bST on pregnancy rates to a t imed
artif icial insemination protocol and to test a resynchronization system
with two consecutive synchronized services. Pregnancy rates were
increased in cows where bST treatment was init iated at 63 ± 3 d
postpartum, compared with cows init iating bST treatment at 105 ± 3 d
postpartum. Combining administration of bST with dietary
manipulation may be beneficial. Billy et al. (2006) examined the
21
effects of bST, pregnancy, and dietary fatty acids on reproductive
responses in lactating dairy cows and found that bST increased milk
production, pregnancy rate (83% vs. 40%) and conceptus length (45 vs.
34 cm). Similarly, Starbuck et al., (2006) found that when lactating
dairy cows, dairy heifers, and lactating beef cows were administered
500 mg bST, artif icial insemination conception rates were improved,
however, the retention of pregnancy was not affected.
Heat stress is often associated with poor reproductive
performance as well as reductions in animal performance and health. To
enable investigation of the effects of bST on reproductive function in
lactating dairy cows during heat stress, Jousan et al. (2007)
presynchronized cows with two injections of PGF2 given 14 d apart
followed by a modif ied Ovsynch protocol. They found that pregnancy
rates did not differ between bST and control cows for f irst and second-
service.
2.9 Dry matter intake and bST
Intake is an important factor that influences nutrient uti l ization,
feed eff iciency and ultimately the profit from the dairy animals.
Vallimont et al. (2001) reported that bST had no effect on DMI or the
digestibi l ity of DM, nitrogen and energy in dairy cows. However,
Santos et al. (1999) demonstrated that cows receiving bST in early
lactation had lower DMI during the f irst 45 d of treatment, whilst
Bauman et al. (1985) and Hartnell et al. (1991) found that with an
extended period of bST administration DMI linearly increased with the
increment of milk production. This increase in DMI occurred within 3
to 5 weeks after bST treatment while the response in milk yield started
within 2 weeks of treatment. This means that initial ly the nutrients for
22
increased milk production must come from body reserves (Peel and
Bauman, 1987) and thus in the f irst few weeks of treatment cows may
experience a period of negative energy balance, depending upon their
energy status at the start of bST treatment, the magnitude of the
production response to bST and the energy density of the ration.
Researchers have suggested various schemes for feeding bST-
treated cows including increasing the amount of grains in feed
(Tessman et al., 1988), feeding a high-energy total-mixed ration ad
libitum (Hutjens, 1990), increasing the amount of energy (Lormore,
1990), increasing the amount of ruminally by passed fat (Chalupa and
Galligan, 1989) or increasing total protein and intake of undegraded
protein (McGuffey et al. , 1991). Every one of these schemes have
revealed very low effects on bST response to intake. However, in a
large f ield study (Thomas et al., 1990), cows were found to respond
well to bST over a wide range of ration nutrient composition.
Preliminary studies have demonstrated that bST responses are greatest
when feed is available for consumption at least 20 hours a day (Patton
and Heald, 1992). These studies showed that when forage quality was
poor, bST response appeared to be reduced. So, overall intake response
to bST can be improved by making the ration more balanced and by
increasing the feeding time.
Intake response to bST, with different dietary energy
concentrations, for the growth performance of bull calves was studied
by Holzer et al. (1999). They found DMI was inversely related to the
energy concentration of the diet and that feed eff iciency was
signif icantly improved by the bST treatment. Peters (1986) also
reported that the level of nutrition may have a large effect on the
response to bST administration.
23
2.10 Dietary energy and bST
Treatment with bST is reported to result in coordination of
metabolism to meet nutrient needs for increased synthesis of milk
components. Bauman et al. (1988) examined the effects of bST on
irreversible loss rate (ILR) and oxidation rate of glucose and
nonesterif ied fatty acids (NEFA) and found that bST treatment
increased milk energy yield by 31% but did not affect feed intake.
Blood glucose concentrations were not affected by treatment; however,
glucose ILR was increased and glucose oxidation was reduced to
accommodate the addit ional glucose (+1.3 mol/d) required for the
increase in lactose secretion. The increases in milk energy yield with
bST treatment caused cows to be in a substantial negative net energy
balance. Other researchers have also investigated the interactions
between bST and dietary energy. McGuffy et al. (1991) reported that
bST increased milk and 3.5% FCM but had effect on DMI and net
energy intake.
Nutritional status of the animal has an effect on the response to
bST treatment. Austin et al. (1991) studied the interactions of bST and
nutrient density during weeks 5 to 20 postpartum. Administration of
bST increased milk production, but augmentation had correlation with
dietary energy and protein. Percentage of milk fat was not affected by
treatment; however, milk protein percentage was reduced with the high
protein and energy diet Kirchgessner et al. (1991) also evaluated
energy metabolism in bST-treated lactating cows and found that
mobil ization of body energy compensated for the bST-induced increase
of milk energy and supported milk production of underfed cows by two-
thirds of the net energy deficit. The uti l ization of mobilized body
energy and ME from the diet for maintenance and milk production was
24
unchanged. The bST and energy deficiency increased N uti l ization for
milk production, because bST increased milk N secretion at the same N
intake, and energy deficiency partly compensated the reduced N intake
by N mobilization.
Administration of bST has variable effects on nutrient uptake.
Miller et al. (1991) reported a potential fourfold increase in NEFA
uptake in bST-treated cows while Tessman et al. (1991) found that
daily injection of bST did not change blood concentrations of glucose
or urea or plasma β-hydroxybutyrate concentrations. Similarly,
McGuire et al. (1992) investigated the relationship bST and dietary
energy and protein status in mid-lactation Holstein cows and found
that milk yield increased for cows fed all diets with bST, but the
response was greatest for those fed the high NE/high CP diet. For all
diets, bST caused an increase in plasma IGF-I (125%) and IGF-II
(21%), with the increase being substantially greater for cows fed the
high NE/high CP diet. Basal insulin levels differed among diets and
increased with exogenous bST in cows fed the high NE and high CP
diet. Leonard and Block (1997) studied the effects of bovine
somatropin on nutrients util ization with either a glucose or insulin
infusion, with their results suggesting that, in early lactation, insulin
was sti l l anabolic because the body weight gain of cows increased.
However, milk yield was stil l higher than that for cows in late lactation
with similar insulin concentrations.
2.11 Dry matter digestibil ity and bST
In a trial on 24 dairy cows, Santos et al. (1999) determined the
digestibi l it ies of DM, organic matter (OM), crude protein (CP), starch,
neutral detergent f iber (NDF) and acid detergent f iber (ADF) in bST
treated animals. Treating cows with bST had no effect on the
25
digestibi l it ies of DM, carbon, and energy, confirming the previous
results of Robinson et al. (1991) who showed that basal metabolism and
maintenance requirements are unaffected by bST treatment. Similarly,
when calculating nitrogen balance, bST administration did not alter
feed digestibi l i ty. In contrast, nutrient demand and metabolism may be
altered by bST administration, but these alterations are attributed to the
animal factors l ike body weight, milk production, milk fat test, and
expected gain or loss of body weight (NRC, 1988).
Santos et al. (1999), while studying the effect of bST with two
types of diets containing corn and sorghum, concluded that bST had no
effect on digestibi l it ies of DM, NDF, ADF, CP and OM for either diet,
and furthermore, no interactions between diets and bST treatment were
observed. Other studies (McGuffey and Wilkinson. 1991) also revealed
no effects of bST on apparent digestibi l i ty of nutrients. However,
Newbold et al. (1997) demonstrated that supply of fermentable energy
may mediate response to bST by increasing the negative energy balance
observed during early lactation. This indicates that digestibi l i t ies of
different nutrients can be increased by providing readily available
source of energy l ike molasses.
2.12 Feed efficiency and bST
The eff iciency of feed util ization is often increased in response to
administration of bST. Bauman et al. (1985) found that when Holstein
cows were treated with either 13.5, 27, or 40.5 mg bST/d average FCM
yield increased in a dose-dependent fashion from 23 to 41%. Overall,
gross lactational eff iciency (milk per unit of net energy intake) was
improved by treatment with bST. Similar results were also obtained by
Solderhalm et al. (1988), who treated Holstein cows with subcutaneous
26
injections of 10.3, 20.6, or 41.2 mg bST daily. Cows treated with bST
consumed 4-10% more feed, but were 11-17% more eff icient than the
controls for conversion of feed to milk. Huber et al. (1997) found that
milk yield and eff iciency of feed uti l ization were enhanced in cows
injected with bST for four consecutive lactations. Santos et al. (1999)
also found that milk yield and efficiency of feed uti l ization were increased
with bST. Similarly, Remond et al. (1991) investigated the effects of
bST (500 mg injected at 14d intervals) with varying level of energy
concentrate in the diet and found that milk yield of bST injected cows
increased 11.0% and that gross eff iciency of milk yield was improved
2.13 Animal health and bST
Treatment of cows with bST is generally associated with no
adverse effects on animal health, although there are some instances
where this may not be the case. Lean et al. (1991) studied post
parturient metabolic disorders and production responses in animals that
had been previously exposed to long-term treatment with bST and
concluded that bST use in a prior lactation may have potential benefit
in reducing risk of metabolic disorders associated with l ipid
mobil ization in the post parturient period.
The effect of bST on the incidence of mastit is appears to be
variable. White et al. (1994) reported that the incidence of clinical
mastitis within a herd was similar, regardless of whether or not the cows
were treated with bST. Zhao et al. (1992) found that mostly the health
and reproduction related variables were not affected by bST treatment,
although the incidence of teat and udder disorders and feet and leg
problems tended to be higher in bST-treated cows. Lack of effect of
bST on the incidence of mastitis was also reported by Collier et al.
27
(2001) who found that bST treatment had no effect on total mastitis
cases, total days of mastit is, duration of mastit is, or the odds ratio of a
cow to develop mastit is. In contrast, Hoeben et al . (1999) found that
bST had a protective effect during experimental Streptococcus uberis
mastitis in cows, whilst Dohoo et al. (2003) found bST increased the
risk of clinical mastitis by approximately 25% and increased the
chances of developing clinical signs of lameness by 55% during the
treatment period.
2.14 Blood metabolites and bST
Treatment of cows with bST affects various blood metabolites.
Guillermo et al, (1990) found blood pH and buffering capacity
decreased as a result of long-term administration of sustained-release
bST. The decrease in buffering capacity was due to decreased
bicarbonate without affecting blood partial pressures of oxygen or
carbon dioxide. Concentration of plasma albumin was decreased and
NEFA, glucose, insulin, bST and IGF-I was increased by treatment.
Total plasma proteins and cortisol, hemoglobin, and hematocrit were
unaffected. Liver DM, total l ipid and triacylglycerol contents, and
plasma 3-hydroxybutyrate and glutamic oxalacetic transaminase were
not affected by bST, but the percentage of triacylglycerol in total l ipids
was increased. These results suggest that bST exhibits lipolytic
activit ies in lactating dairy cows. Responses in blood metabolites may
vary depending on the parity of the cow and the level of bST treatment.
Lean et al. (1992) found that cows treated with 51.6 or 86 mg bST/d
had signif icantly higher serum-free fatty acids than controls. They also
found that older cows treated with 86 mg of bST/d tended to have
higher blood glucose concentrations than control-group cows.
28
Other researchers have also reported parity effects to bST
administration. Skarda et al. (1992) found that administration of bST
resulted in elevated plasma bST during the f irst 9 d after injection;
however, blood erythrocyte and leucocyte counts, haemoglobin
concentrations, haematocrit values, plasma levels of glucose, FFA,
urea, P, serum alanine aminotransferase and aspartate aminotransferase
were not affected. Mishra and Shukla, (2004) in their study with
lactating Murah buffaloes, reported that glucose, triglycerides, total
proteins, albumin, globulin and electrolytes l ike sodium and potassium
were not altered by bST. However, they observed a signif icant decrease
in blood urea nitrogen (BUN) concentration in response to bST
treatment.
Plasma IGF-I concentrations are affected by bST treatment. In
studies involving a prolonged-release formulation of sometribove (N-
methionyl bST) Schams et al. (1991) found that plasma ST increased
signif icantly at d 7 after bST treatment but then decreased on d 14. In
addit ion, plasma IGF-I was posit ively correlated with ST. Rose et al.
(2004) found plasma IGF-I concentrations following injections of bST
was greater low response (LR) cows, whereas the difference in plasma
IGF-I level between week 1 and 3 was greater for the high response
(HR) cows due to lower levels of 3-hydroxy-butyrate and NEFA before
bST treatment. Chaiyabutr et al. (2005) also found that bST increased
the concentration of plasma IGF-I throughout the lactation period,
while plasma glucose, protein and triglyceride concentrations remained
stable. Slaba et al. (2005) measured plasma bST and IGF-I
concentrations in dairy cows following a single subcutaneous injection
of a slowly released preparation of either recombinant enterokinase
linker bST or recombinant methionyl bST. There was a three to seven
29
fold increase in plasma bST concentrations during the f irst three hours
post-injection in cows treated with both sometribove (from 3.4 ± 0.8 to
11.2 ± 3.0 ng/ml) and somidobove (from 2.3 ± 0.3 to 17.5 ± 2.6 ng/ml).
In the next 8 d the bST concentration in the bST-treated cows varied,
but was stil l signif icantly higher than the controls. In the following
days, the concentrations of bST did not differ from the controls.
2.15 Economics and bST
There are variable reports on the f inancial benefit of bST for milk
production. Tauer and Knoblauch, (1997) using data from 259 dairy
farm business in the USA, found that, on average, farms using bST had
25% longer lactation length, produced 510 kg more milk per cow and
net farm income increased by $27 per cow as compared to the farms
where bST was not used. Kinoshita et al. (2004) developed a
comprehensive economic model to evaluate potential impacts of bST in
Japan and concluded that bST can have negative effects in smaller
farms as compared to large farms due to higher costs, and lower profit-
earning ability. Judge et al. (2009) evaluated the economics of four
dairy farms and reported that the overall average change in net farm
income (NFI) attributable to bST was $43.01 per bST-treated cow.
However, profitability of bST use was observed to be quite variable
between farms studied due to the level of production response and the
price received for milk. Similarly, Tauer (2008) using data over the
years 1994 through 2004 for selected New York dairy farms found that
bST increased milk production per cow and decreased the cost of
production per hundredweight of milk.. Mc Bride (2002) assessed the
production and financial impacts of bST adopted U.S. dairy operations
and reported that a substantial increase in milk production per cow is
associated with bST adoption, but large estimated financial impacts
30
were not statistically signif icant because the substantial variation in the
net returns of bST adopters may be related to the management-intensive
nature of bST.
31
CHAPTER -3
Effect of long term use of bovine somatotropic hormone on milk production, reproduction and blood metabolites in Nili- Ravi
buffaloes
ABSTRACT
The objectives of the study were to investigate the effects of
administering bST on milk production, milk composition, reproduction
and hematological and biochemical parameters in Nili-Ravi buffaloes
for a period of three years, from 2004 to 2007. Thirty (n = 30) Nili-
Ravi lactating buffaloes with similar milk production and stage of
lactation were selected and randomly divided in to two groups, A and
B, with 15 animals in each group. Group A (0 bST) served as the
control while animals in group B (+bST) were injected every 14 d with
Boostin-250™ (250mg/animal). Nutritional requirements of the
experimental animals were met through available green fodder (45-50
kg/d) supplemented with concentrate ration at a rate equivalent to half
of the milk production of the animal. Average daily milk production
per animal was 6.76 vs. 7.98 kg for control and treated groups,
respectively. Milk production increased by 18.04% in response to bST
treatment. Numerical variations in the values of the percentages of fat,
SNF, and TS were observed, although the variation of these parameters
in both the groups was non signif icant. The calving interval, dry period
and lactation length were shorter by 14.0, 26.0 and 2.7%, respectively
in the treated group compared with the control. The postpartum estrous
period, service period and services per conception were 98.2 vs. 160 d,
115.10 vs. 207.04 d and 1.31 vs. 1.47 in the bST treated and control
groups, respectively. Statistically, differences were signif icant for
postpartum estrous and service period but for services per conception
32
the difference was non-signif icant. Results indicated positive effect of
bST on reproductive parameters. Prevalence of mastitis was 10.0%
higher in bST-treated animals. Although there were variations in body
weights for animals in groups A and B, these changes over the time of
the study were non-signif icant. The differences among hematological
and biochemical parameters were also non-signif icant except blood
urea nitrogen (p< 0.05), which was higher in the control group. The
economic benefit over a 305 d lactation period with the use of bST was
(Rs. 4227.0).
INTRODUCTION
Pakistan has approximately 27.33 mill ion buffaloes, which
contribute more than 73% of total milk production and 42% of beef
production in the country (Ministry of Food and Economics and
Statistics, 2006). In spite of this large number, per animal productivity
is low as compared with western dairy cattle breeds. The average milk
production is 7-8 kg/d at farm level, which needs to be increased to
make this animal more profitable as well as to meet the protein
requirements of the ever-increasing human population in the country.
Breeding and genetic selection failed to increase much the amount of
milk produced by buffaloes as did for cows (Otto et al., 2003). The
biotechnological treatment (bST) supported by appropriate nutrit ion
and herd management can be a feasible substitute for high buffalo milk
production (Ludri et al. , 1989).
Administration of bST is proved to increase milk yield without
marked changes in composition in dairy animals (Bauman et al., 1985;
Rose et al., 2004; Van Bbaale et al., 2005). It improves the productive
eff iciency due to increased milk yield per unit of feed intake (Bauman,
33
1992). It has no effect on reproductive performance, but tended to
improve some measures of reproduction (Judge et al. , 1999; Silvia et
al. , 2002). Increased milk production in dairy cows with bST has been
shown to be cost effective and without any adverse effects on animal
health (Bauman, 1992).
Little information is available on the use of bST in buffalo, with
only a few studies of short-term duration having been carried out. The
present study was undertaken to investigate the effect of long term use
of bST on productive, reproductive, health, physiological and
biochemical parameters in Nil i-Ravi buffaloes.
MATERIALS AND METHODS
Experimental design
The trial was conducted to study the effect of administration of
bST in Nili-Ravi buffaloes on productive, reproductive, physiological
and biochemical parameters for a period of three years. Thirty (30)
multiparous Nili-Ravi buffaloes with similar stage of lactation and
parity were selected from the herd of the Livestock Experiment Station
Directorate of Livestock Production Research Institute, Bhadurnagar,
and Okara. The average milk yield of the experimental animals was 08
± 1 kg/d and average body weight was 540 ± 15 kg. The animals were
randomly divided in to two groups, A and B, with 15 animals in each
group. Group A was kept as control, while group B was exogenously
injected with the (bST) Boostin -250™ (manufactured by LG Life
Sciences, Ltd. South Korea and distributed by M/S Ghazi Brothers,
Pakistan). The dose level was 250 mg/ animal as recommended by the
manufacturer and subcutaneous injection was given at fortnightly
34
interval after 60 ± 3 d postpartum until the end of lactation. The same
pattern of bST administration was followed in the subsequent
lactations.
Experimental ration
The nutrit ional requirements of experimental animals were
fulf i l led according to NRC (2001) on the basis of body weight and milk
production through the provision of green fodder and concentrates.
Maintenance requirements were largely met through available green
fodder. Winter fodders were chopped berseem (Trifolium pretense) and
lucerne (Medicago sativa) mixed with wheat straw, while summer
fodders were chopped maize (Zea mays), sorghum (Sorghum bicolor)
and sadabehar (Sorghum bicolor x Sudanense). The average chemical
composition of these fodders is presented in Table 1. The daily
allowance of 50 ± 5 kg fodders/d was provided to each (individual)
animal. The milk production requirements were met through provision
of the concentrate ration, which contained 17.39% CP and 2.45 Mcal
ME/kg on DM basis. Concentrate was offered individually at the time
of milking on the basis of daily milk production. The composit ion of
concentrate ration is given in Table 2.
Feeding program
Chaffed, green fodder was fed to the animals in the shed while
the concentrate mixture was offered at the time of milking. The
concentrate was fed at a rate equivalent to half of their average weekly
milk production. Samples of feed and green fodder were collected at
fortnightly interval and analyzed for proximate analysis according to
AOAC (1995). The gross energy of the ration was determined through
the IKA C-2000 Bomb Calorimeter, while metabolizable energy was
35
calculated as 63% of the gross energy (Mandal et al ., 2003). The
analysis was done in the Nutrition Laboratories of the Department of
Food and Nutrit ion, University of Veterinary and Animal Sciences,
Lahore.
Management of animals
During the experimental period, homogeneous management
practices were adopted for al l animals. They were housed in the same
shed equipped with shade, mangers and water troughs; the shed was
partitioned to accommodate both groups separately. The vaccination
schedule was followed against contagious diseases (especially
Hemorrhagic septicemia and Foot and Mouth Disease) according to
farm routine, whereas for the control of parasitic infestation, animals
under tr ial were dewormed with a broad-spectrum anthelminthic
(Nilzan plus™) twice a year.
The fol lowing parameters were studied to see the influence of bST.
1. Milk production and composition
Buffaloes were hand milked twice daily at 02.00 and 14.00 h and
milk production at each milking was weighed and recorded. Daily milk
recording commenced 3 d post-parturition and continued until the
completion of lactation. Milk was sampled from consecutive a.m and
p.m milking each week and composited for analysis. Milk samples were
used to determine fat %, and SNF %, using the Gerber and Rapid
methods, respectively as described by FAO (1986a and 1986b). Total
solids % was determined by the Gravimetric method according to
AOAC (1990).
36
Table 1
Average chemical composition of fodders Fodders DM
(%) CP (%)
NDF (%)
ADF %
ME (Mcal/kg)
Ca (%)
P (%)
Winter Fodders
Berseem (Trifolium
pretense) 20.23 18.82 51.32 41.97 2.17 1.66 0.33
Lucerne (Medicago
sativa) 24.95 21.25 52.67 40.59 2.24 2.00 0.32
Wheat straw 92.75 2.59 80.9 50.2 1.55 0.30 0.07
Summer Fodder
Maize (Zea mays) 25.93 7.20 66.01 34.11 2.0 0.52 0.28
Sorghum (Sorghum
bicolor) 28.8 6.86 67.09 37.90 1.86 0.58 0.12
Sadabahar
(Sorghum bicolor x
Sudanese)
24.16 9.70 65.06 41.64 1.79 0.65 0.17
DM = dry matter, CP = crude protein, NDF = neutral detergent f iber, ADF = acid detergent f iber, ME = metabolisable energy, Ca = calcium, P = phosphorus
37
Table 2 Composition of concentrate ration Ingredients Percentage
Maize grain 10.00
Rice polishing 8.00
Wheat bran 22.00
Cotton seed cake 14.00
Canola meal 10.00
Maize gluten meal 30 % 22.00
Molasses 12.00
Mineral mixture* 2.00
Chemical composition
Dry matter (%) 91.00
Crude protein % 17.39
Metabolisable energy (Mcal/kg) 2.45
Neutral detergent f iber (%) 32.17
Acid detergent f iber (%) 18.30
Calcium (%) 0.70
Phosphorus % 0.45
* Mineral mixture composition (/kg) Dicalcium phosphate 708 g; Sodium choloride 189 g; Magnassium sulphate 86.0 g; Ferous sulphate 8.9 g; Manganese sulphate 4.9 g; Zinc sulphate 3.2 g; Copper sulphate 0.3 g; Potassium iodide 0.087 mg and Cobalt chloride 0.0089 mg ; Sodium selenate 0.015 mg.
38
2. Reproductive parameters
During the experiment the animals were closely observed for
response in reproductive parameters under the influence of bST
hormone.
2.1 Postpartum estrous
The exhibition of heat (estrus) in the cows was detected through
twice daily (2 h) exposure to vasectomised bulls at 5.00 and 17.00 h.
Observations on the onset of estrous were recorded for individual
animals in both of the groups.
2.2 Services per conception
The animals were inseminated using artif icial insemination
technique. The number of services for establishing pregnancy were
recorded for each animal.
3. Health data
The animals were watched closely for any ailment (infectious and
metabolic) and any incidences were recorded. The animals were also
monitored for udder health by carrying out the sub-clinical mastitis test
(Muhammad et al., 1995) on a weekly basis.
4. Physiological parameters
Blood samples were collected every 14 d by puncturing of the
jugular vein and collecting blood in two (10×100mm) evacuated tubes;
one containing sodium heparin and the other without anticoagulant. For
those animals in Group B the blood was collected prior to the bST
injection. Immediately fol lowing collection, the blood samples were
39
placed on ice. The collection tubes containing 0.2 ml sodium heparin
were used for determination of erythrocyte sedimentation rate with
wstertergen sedimentatation tubes followed by Benjamin, (1985). The
Pack cell volume was noted as percentage with the help of hematocrit
scale explained by Bush, (1991). While, the haemoglobin contents of
the plasma were monitored through Sahili ’s Apparatus described by
Sastry, (1983). However, the tubes without anticoagulant were allowed
to clot, centrifuged at 3000 RPM for 30 min. at 5°C and then the
harvested serum was stored in capped glass bottles at -4°C til l analysis.
For determination of blood chemistry, preserved samples of serum were
analyzed by using Cecil 2041 single beam spectrophotometer with
Randox Kits developed by Randox Laboratories Ltd. United Kingdom. However, non-metal elements like sodium and potassium were
determined through Sherwood flame photometer-410 in the laboratories
at University of Veterinary and Animal Sciences, Lahore.
5. Statistical Analysis
Data on productive parameters (milk production, lactation length,
dry period and calving interval), milk composition (fat, SNF, TS),
reproductive parameters (postpartum estrus, service period and services
per conception) and blood metabolites (blood glucose, blood urea
nitrogen, total protein, cholesterol, total l ipids, calcium, sodium,
potassium, Hemoglobin, ESR and PCV) were statistically analyzed by
student’s t-test using MINITAB® software package of statistical
analysis.
40
RESULTS AND DISCUSSION
Milk production
The weekly milk production pattern in both the groups during
the f irst year of the study is shown in Figure 1. During this f irst year
the average daily milk yield of groups A and B was 6.57 and 7.76 kg,
respectively (Table 3), representing an increase (P<0.05) in milk
production of 18.11% in response to bST treatment. These findings
are agreement with those of Jorge et al. (2002), Mishra and Shukla,
(2004) who found that the increase was 14.93 to 32.4% in treated
Murrah and Kundi buffaloes, respectively, although the increase
depended on the dose rate of bST.
During the second year of the study the average daily milk
yield of groups A (control) and B (treated) was 7.64 and 8.09 kg,
respectively (Table 3). The weekly milk production pattern in both the
groups is given in Figure 2. The increase in milk production in the
treated group (B) over the control (A) was 5.90 %, which was much
less than the response in the f irst lactation, and furthermore the
difference observed in the second year was non signif icant (P>0.05).
This response to bST in the second year may have been confounded due
a number of animals contracting FMD. Given that more animals (11) in
the bST-treatment group (group B) were infected than in the control
group (8), this would have had a greater impact on average milk yields
of the bST-treated group. This argument for the lower response in the
second year is supported by Bauman, (1992) who reported that poorly
managed farms, where animals are stressed, underfed or sick will have
achieved negligible milk response to bST. However, it is also possible
that the lower response to bST in the second year was not due to the
41
health status of the animals as Hansen et al. (1994) found the increase
in milk production during the second year (of bST treatment) was
decreased by an amount equivalent to 67% of the total increase
observed in the f irst year of use of bST in dairy cows.
The average daily milk yield for the third consecutive year was
5.97 and 8.11 kg for group A and B, respectively (Table 3),
representing a 35.84% increase (P<0.05) in milk yield in response to
bST. The weekly milk production trend of both experimental groups is
reflected in Figure 3, showing a similar trend as observed in the f irst
and second years. The increase in milk yield of the bST-treated animals
may not have been due entirely to bST as some of the animals within
this group were parity 3 (peak lactation) whilst all animals in the
control group were parity at declined lactation. However, the results of
the present study were consistent with those of Jorge et al. (2000), Nisa
et al. (2006) and Sarwar et al. (2007) who reported that bST
administration in buffaloes increased milk production from 30 to 37%.
Over the entire trial period, the average daily milk production
was 6.76 vs. 7.98 kg in control and treated group, respectively (Table
3, Figure 4); representing an increase (P<0.05) of 18.04% in response
to bST treatment. Similar results have been reported in previous
studies. Huber et al. (1997) reported that milk production was
increased by 14% in dairy cows injected every 14 d with 500 mg bST
for four consecutive lactations. Hemken et al. (1991) also reported
that milk production was increased in dairy cows receiving bST for
two consecutive lactations. The increment in milk production may be
that bST is a homeorhetic controller that shifts the portioning of
nutrients so that more are used for milk synthesis (Peel and Bauman,
1987). Thus, effects are primarily, perhaps exclusively, on directing
42
the use of absorbed nutrients. This involves coordinating the
metabolism of various body organs and tissues; these orchestrated
changes in tissue metabolism involve both direct effect on some tissue
and indirect effects mediated by somatotropic hormone dependent
somatomedians (IGF-I) for other tissues like mammary glands
(Bauman, 1992). The mechanism of bST to exert its galactopoietic
effect is complex and involves a multiplicity of events in the whole
animal. Increases in the availability of glucose with in the mammary
epithelial cell in response to growth hormone treatment would result
in increases in rate of lactose synthesis and hence stimulation of milk
production. Increases in the concentration of IGF-I in milk and plasma
could be one of the processes involved in stimulation of milk
synthesis (Faulkner, 1999). In addition, bST appears to promote milk
production by a partitioning effect on absorbed nutrients so as to
supply more substances for mammary synthesis and also the level of
nutrition may influence yield responses for milk and nutrient f low
(Bauman and Currie, 1980). The increase in milk synthesis most likely
involves changes in the activity of key regulatory enzymes resulting
in an increased synthesis rate per epithelial cell.
Lactation length
The average lactation length of the treated (+bST) and control
(0 bST) groups were 259.4 vs.264.0, 256.2 vs. 275 and 251.0 vs. 0 d
for lactations 1, 2 and 3, respectively (Table 4). Relatively, the
lactation length of the control group was longer to that of treated
(+bST) group, although this difference was not statistically signif icant
(P>0.05). No animal in the control (0bST) group calved and
completed their 3rd lactation during study period, while five out of fifteen
43
(5 /15, 33.3%) of the bST-treated group calved and completed their 3rd
lactation.
The overall mean lactation length group for treated (+bST) and
control (0 bST) groups was 253.0 and 260.0 d, respectively (Table 5
and Fig. 5). However, this difference was not statistically signif icant
(P>0.05). This indicates that bST does not have negative effect on
productive traits in buffaloes, which agrees with the results of
Bauman et al. (1999) and Jones (2000) who reported that rbST
treatment with good management had no negative effect on productive
and fertil ity traits in cattle.
0
2
4
6
8
10
12
1 3 5 7 9 11 13 15 17 19 21 23 25 27
Weeks
Milk
yie
ld (
kg/d
)
Treated
Control
Figure 1. Trend of milk production in control and bST-treated groups
during the f irst year of the study.
44
0
2
4
6
8
10
12
1 4 7 10 13 16 19 22 25 28 31 34 37 40
Weeks
Milk
yie
ld (
kg/d
)
Treated
Contol
Figure 2. Milk production pattern in the control and bST-treated
groups during the 2nd year of the study.
0
2
4
6
8
10
1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35
Weeks
Milk
yie
ld (
kg/d
)
Treated
Control
Figure 3 Trend of milk production in the control and bST-treated
groups during the 3rd year of the study.
45
0
2
4
6
8
10
12
1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39
Weeks
Milk
yie
ld (
kg/d
)
Treated
Control
Figure 4. Comparison of milk production in control and bST-treated
groups over the 3 year study period.
Table 3.
Effect of bovine somatotropic hormone administration on average milk yield of Nili- Ravi buffaloes (means ± SE)
Parameters
Study period
Group A (0 bST)
Group B (+bST)
Yield SE Yield SE
Milk
production
(kg/day)
Year-1 6.57 a 0.29 7.76 b 0.33
Year-2 7.64 a 0.33 8.09 a 0.31
Year-3 5.97 a 0.23 8.11 b 0.20
Overall 6.76 a 0.25 7.98 b 0.26
Means within row bearing different superscripts differ significantly (P<0.05). SE = Standard error bST= Recombinant bovine somatotropic hormone.
46
Dry period
The average length of the dry period following the f irst lactation
was 204.2 vs.246 d for the bST-treated and control groups,
respectively. The average length of the dry period for the bST-treated
group during the second lactation was 160 d (Table 4). No animal in
the control (0bST) group calved and thus none completed their 3rd
lactation during the study period. The overall average length of the
dry period in treated and control groups were 182.1 vs. 246.0 d,
respectively (Table 4), although these values were not signif icantly
different (P>0.05). The trend in length of the dry period is shown in
Figure 5.
Calving interval
Between the f irst and second lactations the average calving
interval of bST-treated and control groups were 460 and 506 d,
respectively, although these values did not differ signif icantly
(P>0.05). The intercalving interval between the second and third
lactations could only be determined for the bST-treated group and
which was 410 d. Despite being unable to determine the average
intercalving interval of the control group over the entire study period,
the fact that the control group animals did not calve in the f inal year
of the study is the basis for concluding that bST-treatment resulted in
a decrease in the intercalving interval. The relative shorter period may
be due to improvement in fertil ity because higher peak in
progesterone production has been reported in the f irst two cycles of
bST treated cows and it was suggested that this may have been due to
ovarian IGF-I mechanism (Gallo and Block, 1990). The results of the
present study are in agreement with those of Thomas et al. (1990) and
Jones (2000) who reported that bST treatment with good management
47
has no negative effect on productive and fertil ity traits in cattle. In
the study presented here, bST-treatment had a positive effect on
fertil ity traits by decreasing the intercalving interval.
Table 4
Effect of recombinant bovine somatotropic hormone on productive traits of Nili- Ravi buffaloes (mean ± SE)
Parameters
Parity
Control (0 bST)
Treated (+ bST)
Days SE Days SE Lactation
persistency
Dry period Calving interval
Lactation -1
Lactation -2 Lactation –3 Overall average Lactation -1 Lactation -2 Overall Average
Lactation -1 Lactation -2 Overall average
264.1
275.1
--
260.0
246.0
--
246.0
506.0
--
506.0
15.0
12.0
---
9.5
34.0
--
34.0
33.0
---
30.0
259.4
256.2
251.0
253.0
204.2
160.0
182.1
460.0
410.0
435.0
8.8
13.0
4.2
6.0
27.0
22.0
20.0
30.0
20.0
23.0
SE= standard error. bST= Recombinant bovine somatotropic hormone.
48
Figure 5. Comparison of lactation length (LP), dry period (DP) and calving interval (CI) in bST-treated and control groups during the study period
Milk composition
Administration of bST had no effect (P>0.05) on any of the
measures of milk components. The average milk composition over the
study period were 6.79 vs. 6.75% fat, 9.36 vs. 9.27% SNF, and 16.15
vs. 16.00% TS for bST-treated and control groups, respectively (Table
5). A comparison of milk components over the study period is shown in
Figures 6, 7 and 8). Linn (1987) observed variations in bST production
trials and reported that there can be minor changes, primarily in fat
content of milk, during the f irst few weeks of bST administration due to
adjustments in the cow’s metabolism and voluntary feed intake.
However, these changes only temporary and negligible when compared
with variations normally occurring over a lactation cycle. Other
researchers, for example, Barbano et al. (1992), Jorge et al. (2002),
Chalupa et al. (1996), Mishra and Shukla (2004), and Khattab et al.
49
(2008) also found that bST did not influence the milk composition of
dairy cows, Murrah, Kundi and Egyptian buffaloes, respectively.
However, Huber et al. (1997) reported that fat percent was decreased in
dairy cows with long term use of bST. Such differences may be due to
variation in the quality and quantity of feed offered to the animals
under trial. The results of the present study are also different from
those of Eppard et al. (1985), Mc Bride et al. (1989) and Capuco et al.
(2001) who showed that milk fat percentage increased in response to
bST treatment. An increase in fat content of milk during bST
administration is often caused by an extra mobilization of the fat
reserves of the animal. Greater increases in fat percent with bST
administration have been observed when cows were in negative energy
balance (Peel et al., 1989). Similarly the results of McGuffey et al.
(1990) are also not in agreement with the present findings as they
observed a signif icant decrease of TS in milk obtained from bST-
treated animals.
50
Table 5.
Effect of bovine somatotropic hormone administration on milk components of lactating Nili–Ravi buffaloes over the 3 year study period (mean ± SE)
Parameters Study period
Control ( 0 bST)
Treated ( + bST)
Percent SE Percent SE Milk components Fat Solid not fat (SNF)
Total solids (TS)
Year -1 Year-2 Year-3 Over all Year -1 Year-2 Year-3 Over all Year -1 Year-2 Year-3 Over all
6.54
6.79
6.89
6.75
9.25
9.28
9.29
9.27
15.79
16.04
16.18
16.00
0.04
0.06
0.08
0.05
0.04
0.06
0.03
0.01
0.08
0.08
0.12
0.05
6.66
6.87
6.83
6.79
9.36
9.38
9.34
9.36
16.04
16.25
16.17
16.15
0.05
0.07
0.07
0.06
0.03
0.06
0.06
0.04
0.07
0.12
0.11
0.09 SE= standard error. bST= Recombinant bovine somatotropic hormone.
51
Figure 6 Comparison of yearly and overall milk fat % of bST-treated
and control groups over the study period
Figure 7 Comparison of yearly and overall milk solid not fat % of bST-treated and
control groups during the study period.
9.15
9.2
9.25
9.3
9.35
9.4
Year -1 Year-2 Year-3 Over all
Study period
Per
cen
t
Treated
control
9.15
9.2
9.25
9.3
9.35
9.4
Year -1 Year-2 Year-3 Over all
Study period
Per
cen
t
Treated
control
52
Figure 8 Comparison of year wise and overall milk total solids % of
bST-treated and control groups during the study period.
Reproductive performance
The reproductive parameters in terms of postpartum estrus days,
service period and services per conception were studied for three
consecutive years to know the long-term effect of bST on fertil ity of
buffaloes. The postpartum estrus days were 139.0, 103.6 and 98.20,
service period was 156, 126.5 and 62.58 d and services per conception
were 1.26, 1.46 and 1.2, respectively in the bST-treated group for
lactations 1, 2 and 3. For the control group the postpartum estrus days
were 175.0 and 239.08, the service period was 175.0 and 239.08 d and
services per conceptions were 1.73 and 1.21 for lactations 1 and 2,
respectively (Table 6). Within the control group of animals, none
calved for their third lactation during the three year study period, while
in the bST-treated group all completed their 2nd lactation and 33% of
15.5
15.6
15.7
15.8
15.9
16
16.1
16.2
16.3
Year -1 Year-2 Year-3 Over all
Study period
Per
cen
t
Treated
control
53
the animals calved for their 3rd lactation. The overall means of
postpartum estrus were 98.20 vs. 160.0 days, service period 115.0
vs.207.04 and services per conception 1.31 vs. 1.47 for the bST-treated
and control groups, respectively. The improvement was observed in
treated group over the control. The statistical analysis revealed that
there was signif icant improvement (P<0.05) in postpartum estrus and
service period in treated group over the control. However, the
improvement was non signif icant (P>0.05) in services per conception
for experimental animals. The results of the study are supported by the
results of Spicer et al. (1990).who reported that granola cells in the
bovine ovary apparently produce IGF-I that acts synergistically with
FSH to increase the production of estrogen and progesterone hwhich
have ultimately effect on reproductive performance in dairy cows.
Health parameters
The effect of long-term administration of bST on the health of
Nili–Ravi buffaloes was monitored through observation of the
incidences of both contagious and non-contagious diseases. The
incidences of mastitis for bST-treated and control group were 5.0 vs.
2.0, 9.0 vs.7.0 and 4.0 vs.5.0 in years 1, 2 and 3 respectively (Table 7).
The increase of mastitis incidences in treated group over the control
was 28.47%., although this increase was non signif icant (P>0.05).
These findings are in agreement with those of White et al. (1994) and
Collier et al. (2001) who found rbST did not increase the risk of
clinical mastitis; instead they found but a positive linear relationship
existed between milk yield and mastitis incidence.
54
Table 6.
Effect of bovine somatotropic hormone administration on reproductive parameters of lactating Nili–Ravi buffaloes during the study period
Parameters
Parity
Control (bST 0)
Treated (bST+)
Days SE Days SE Post partum
estrus
Service period/open
day
Number of services per conception
(Nos.)
Lactation-1
Lactation -2
Lactation-3
Over all
Lactation-1
Lactation -2
Lactation-3
Over all
Lactation-1
Lactation -2
Lactation-3
Over all
145.00
175.00
--
160.00
175.00
239.00
---
207.04
1.73
1.21
---
1.47
11.00
14.00
9.30
22.00
23.00 -
17.00
0.03
0.21
--
0.2
139.00
103.06
52.00
98.20
156.00
126.50
62.80
115.10
1.26
1.46
1.24
1.31
11.00
11.00
14.00
8.30
19.00
18.00
6.50
12.00
0.17
0.50
0.40
0.09
Means with in row bearing different superscripts differ significantly (P<0.05). SE= standard error. bST= Recombinant bovine somatotropic hormone.
55
Figure 9 Comparison of reproduction parameters (post partum estrus [PPE], service period [SP]) of bST-treated and control groups during the study period.
The overall incidences of Foot and Mouth disease were 11.0 vs. 10.0
for the bST-treated and control groups, respectively (Table 7). The
difference in the incidences was non signif icant (P> 0.05) in treated and the
control groups. Only one incidence of lameness was observed during the
study in each group. The lameness was may be the after effect of FMD. On
the overall, the results are in agreement with Burton et al. (1990) who
reported no signif icant difference in the incidence of lameness or hoof
injuries in bST-treated animals.
56
Blood metabolites
During the study period, serum from blood samples collected
from both groups of animals was analyzed for hematology, nutrient
metabolites and mineral contents.
Hematological parameters
The overall (3 year) average hematological parameters for ESR,
HCV and Hb content of control and bST-treated groups were 70.50 vs.
70.70 mm/Ist h, 35.10 vs. 34.55% and 13.00 vs. 13.26 g/dl, respectively
(Table 8). Statistically, al l differences were non signif icant (P>0.05).
These results are similar to those of Mishra and Shukla (2004) who
reported that bST had no effect on hemolymphatic (blood) system of
dairy buffaloes. In contrast, Rowlands et al. (1979) observed a decrease
(p<0.05) in hematological parameters including HCV, ESR and Hb of
bST-treated dairy animals. The relative difference may be due to stage
of lactation and dose of bST used, because init iation of lactation leads
to an increase in the vascular bed, followed by an increase in blood
volume, whereas Hb concentration is directly related to PCV (Schams
et al. 1975).
57
Table 7
Effect of bovine somatotropic hormone administration on the health of lactating Nili- Ravi buffaloes
Period Diseases Treated
Control
(No. of cases) (No. of cases)
First year
Foot and mouth disease - -
Mastitis 5.0 2.0
Theileriosis - -
Lameness 2.0 4.0
Second year
Foot and mouth disease 11.0 10.0
Mastitis 9.0 7.0
Theileriosis - -
Lameness 1.0 1.0
Third year
Foot and mouth disease - -
Mastitis 4.0 5.0
Theileriosis - 1.0
Lameness - -
Overall
prevalence
Foot and mouth disease 11.0 10.0
Mastitis 18.0 14.0
Theileriosis - 1.0
Lameness 1.0 1.0
58
Table 8
Effect of bovine somatotropic hormone administration on the hematology of lactating Nili –Ravi buffaloes (mean ±SE)
Parameters Study period
Control (0 bST)
Treated (+bST)
Concentration SE Concentration SE
Erythrocyte sedimentation
rate (ESR)
(mm/Ist hr)
Year -1
Year-2
Year-3
Over all
70.50
60.10
80.90
70.50
4.20
6.20
4.10
2.60
71.70
64.30
76.10
70.70
3.80
4.60
5.40
1.54
Hematocrit value
(HCV) (%)
Year -1
Year-2
Year-3
Over all
31.85
36.34
37.12
35.10
0.62
0.46
0.85
0.73
32.27
35.24
36.15
34.55
0.76
0.58
1.10
0.52
Hemoglobin (g/dl)
Year-1
Year-2
Year-3
Over all
12.62
13.63
13.74
13.00
0.19
0.29
0.32
0.30
12.72
13.26
13.80
13.26
0.18
0.24
0.38
0.34
SE = standard error. bST= Recombinant bovine somatotropic hormone mm / Ist hr = millimeter first hour.
Biochemical parameters
The overall (over the 3 years study period) average biochemical
parameters including plasma total protein, total l ipids, BUN,
cholesterol and glucose of the control and bST-treated groups were 8.29
vs. 8.39 mg /dl, 533.0 vs. 531.1 mg /dl, 4.41 vs. 4.11 mmol /L, 162.92
59
vs. 159.2 mg /dl and 55.22 vs. 57.0.3 mg/dl, respectively (Table 9). The
results of all parameters except BUN were non signif icant (P>0.05);
BUN was signif icantly lower (P<0.05) in the-bST treated group
compared to the control. Lower value of BUN is an indication of more
eff icient util ization of protein. Mishra and Shukla, (2004) also found
that bST had no effect on biochemical parameters except BUN of the
dairy Murrah buffaloes. The present results partially agree with those
of Chaiyabutr et al. (2005) who found that bST had no effect on plasma
glucose, total protein and l ipids in dairy cows. In contrast, the present
observations were not in agreement with of Helal and. Lasheen (2008),
who found that the plasma protein and glucose concentrations were
signif icantly increased, while blood urea and cholesterol remained
unaffected in bST-treated (500 mg/14 d) in Egyptian dairy buffaloes.
Mineral metabolites
The overall average serum sodium, potassium and calcium
concentrations of the control and bST-treated groups were 144.90 vs.
137.36, 6.31 vs. 6.6.28 and 4.49 vs. 4.54 meq/L, respectively (Table
10), with none of the differencs being signif icant (P>0.05). McGuffy et
al. (1990) also found sodium chloride and potassium concentrations
were not signif icantly different between bST-treated and control dairy
cows
60
Table 9
Effect of administration bovine somatotropic hormone on blood metabolites in lactating Nili –Ravi buffaloes (mean ±SE)
Parameters Study period
Control (0 bST)
Treated (+bST)
Concentration SE Concentration SE
Protein Mg/dl
Year-1 Year-2 Year-3
Over all
8.48 7.92 8.46 8.29
0.08 0.12 0.20 0.08
8.37 8.11 8.70 8.39
0.07 0.98 0.18 0.07
Lipids mg/dl
Year -1 Year-2 Year-3
Over all
549.9 576.3 472.7 533.0
9.4 21.0 6.6
13.9
564.7 554.1 474.5 531.1
8.5 15.0 3.8
12.7
Blood urea
nitrogen mmol/l
Year -1 Year-2 Year-3
Over all
4.32 a 4.02 a 4.91 a 4.41 a
0.13
0.07
0.16
0.11
3.95 b
3.80 b 4.59 a 4.11 b
0.04
0.05
0.08
0.06
Cholesterol
mg/dl
Year -1 Year-2 Year-3
Over all
173.83 157.03 157.9
162.92
1.8 1.9 5.0
2.44
170.95 154.4 152.2 159.2
2.5 3.4 4.3
2.63
Glucose
G/dl
Year -1 Year-2 Year-3
Over all
55.49 55.37 54.82 55.22
2.1 1.7 2.9
0.86
57.22 56.80 57.0.7 57.03
1.4 2.0 2.4
0.77
SE = standard error mmol = mill i mole bST= Recombinant bovine somatotropic hormone.
61
Table 10
Effect of bovine somatotropic hormone administration on mineral metabolites of lactating Nili –Ravi buffaloes (mean ±SE)
Parameters Study period
Control (0 bST)
Treated (+bST)
Concentration SE Concentration SE
Sodium (meq/l)
Year-1
Year-2
Year-3
Over all
131.70
135.69
155.50
144.90
3.40
4.70
7.20
8.00
124.70
137.79
149.60
137.36
4.50
4.40
8.10
7.10
Potassium (meq/l)
Year -1
Year-2
Year-3
Over all
6.41
6.35
6.17
6.31
0.40
0.34
1.07
0.60
6.31
6.43
6.11
6. 28
0.89
0.41
0.88
0.72
Calcium (meq/l)
Year -1
Year-2
Year-3
Over all
4.71
4.60
4.17
4.49
0.45
0.53
0.70
0.56
4.74
4.63
4.23
4.54
0.43
0.64
0.56
0.55
bST = recombinant bovine somatotropic hormone. SE = standard error meq = mil l i equivalent
62
Economics of milk production
The average daily milk production in bST treated and control
groups was 7.98 and 6.86 kg, respectively throughout the experimental
period. The average price per ki logram of milk in the peri- urban area
was Rs. 25.0. Therefore, the daily net income per animal was Rs 92.00
vs 78.14 in the bST-treated and control groups, respectively. Increased
net income in the bST-treated group was Rs.13.86/d. Hence the net
profit (of bST-treatement) per animal over the 305 d lactation was
Rs.4227.3 (Table 11), thus indicating that the use of bST for increasing
milk production is economical. These results are with agreement with
Tauer and Knoblauch, (1997) who studied the economics of dairy farms
and reported that net farm income increased by $27.0 per cow
compared to the farms where bST was not supplemented to dairy cows.
The economics of using bST may vary depending on farm size and the
management of farm. Kinoshita et al. (2004) who reported that bST had
negative effect in smaller farms as compared to large ones due to
higher cost and lower profit earning abili ty.
63
Table 11
Economics of the use of bovine somatotropic hormone in lactating Nili-Ravi buffaloes.
Parameters Treated (+bST)
Control (0bST)
Av. daily feed intake/ animal (kg)
13.22 12.98
Value of feed @ Rs.7.0 / Kg
92.54 90.86
Cost of bST/animal /day
15.0 -------
Total cost (Feed + bST) /day (Rs.)
107.50 90.86
Av. daily milk yield / animal (kg)
7.98 6.86
Value of milk @ Rs. 25 / kg
199.50 169.00
Net income Rs./day/animal
92.00 78.14
Net daily income in profit (Rs.)
13.86 ------
Net per animal prof it over lactation of 305 Days (Rs.)
4227.30 ----
bST = recombinant bovine somatotropic hormone. Rs. = Pakistan rupees
64
CHAPTER-4
Production performance of lactating Nili-Ravi buffaloes under the influence of somatotropic hormone with varying levels of
dietary energy
ABSTRACT
The study was conducted to determine the effect of dietary energy
on milk yield and its composition under the influence of bST in Nili
Ravi buffaloes. Multiparous buffaloes (n=12) at mid lactation and
similar level of production were selected and randomly divided into
three groups (A, B and C) with four animals in each group in a
completely randomized design. All the experimental animals were
injected bST at fortnightly intervals after 60 ± 3 d postpartum for a
period of 90 d. The nutritional requirements of these animals were met
through a total mixed ration with different densities of energy (low
energy density, 85 %; medium energy density, 100 %; and high energy
density, 115 % of NRC, 2001 standards). The increase in milk yield on
the high energy density (HED) ration was signif icantly higher (P<0.05)
than for the low energy density (LED) and medium energy density
(MED) diets. The difference in the milk yields between the LED and
MED rations was non signif icant (P>0.05). Feed eff iciencies were 0.61,
0.66 and 0.74 on LED, MED and HED diets (P<0.05), respectively.
Nutrient intake (except for ether extract) was signif icantly (P<0.05)
higher on the LED ration than the other two other rations. However,
milk composit ion and body weight gain were similar for all the rations.
Results indicated that 15% higher energy than recommended by NRC,
favored milk production in Nili-Ravi buffaloes when they were injected
with bST hormone.
Key words Bovine somatotropic hormone; Nili-Ravi buffaloes; milk
yield; dietary energy.
65
INTRODUCTION
Bovine somatotropin improves eff iciency of milk yield by
partitioning nutrients toward the mammary gland for increased milk
synthesis (Snatos et al., 1999). Response to bST is dependent on
overall management practices before and after initiation of treatment
(Bauman, 1992). A reduced response might be associated with the
energy and metabolic status of the cow (Leonard and Block, 1997). In
early postpartum, high yielding cows experience a negative energy
balance because of low energy intake relative to energy demand for
maintenance and milk yield, which may l imit their abil ity to respond to
exogenous bST. During periods of negative energy balance endogenous
bST is high, but concentrations of IGF-I and insulin are low and have
ult imately effect on plasma level of l ipitin, which counteract on milk
production of the cow (Block et al. , 2001).
Energy requirements are increased because milk yields are
elevated by bST. The requirements appear to be met primari ly by an
increase in feed intake or, when cows are in negative energy balance,
by lipid mobil ization (Peel and Bauman, 1987). Because the restoration
of body energy stores during late lactation is important to milk yield in
subsequent lactations, dietary fat supplements fed in early lactation and
during bST treatment may help to increase the energy density of the
ration and to improve the metabolic eff iciency of energy uti l ization for
milk production (Srivastava and Mudgal, 1984). However, some studies
have shown that dietary energy concentration in excess of NRC
recommendations does not signif icantly affect responses to bST for any
variables measured (Hemken et al. 1991; Lormore et al. 1990). The
objective of study was to determine the optimum dietary energy level
for lactating buffaloes receiving exogenous bST.
66
MATERIALS AND METHODS
Experimental design
A 90-d feeding tr ial was conducted to determine the optimum
level of energy in the ration of Nil i-Ravi buffaloes being administered
bST. For this study 12 multiparous buffaloes in mid-lactation having
similar milk yield (8.0±1kg/d) and parity were selected from the herd
maintained at the Livestock Experiment Station Rakh Dera Chahal,
Lahore. These animals were randomly divided in to three groups i.e. A,
B and C with four animals in each group. All the experimental animals
were injected with bST (Boostin -250™). The dose level was 250
mg/animal and injection was given at fortnightly intervals during study
period. The study lasted for three months.
Experimental rations
The maintenance and production requirements of individual
animal were met through total mixed rations (TMR) with varying levels
of metabolizable energy (ME). Three isonitrogenous experimental diets
with varying levels of energy (100%, 15% below and 15% above the
recommendations of NRC, 1989) were prepared. The TMR was fed
twice daily to individual animals and water was offered ad libitum. The
ingredients and composition of the rations is presented in Table 1.
67
Table 1
Ingredients and chemical composition of total mixed rations offered to bST treated Nili Ravi buffaloes
Ingredients A B C
LED MED HED
Corn gluten meal 30% 10.00 11.50 19.00
Corn gin - 12.50 15.00
Rice polishing - 10.50 19.00
Wheat bran 25.00 6.00 -
Cotton seed cake 15.00 11.00 -
Sun flower meal 5.50 7.50 6.50
Wheat straw 25.00 24.00 22.00
Molasses 17.50 14.50 13.00
Magalac* - 1.00 4.0
Mineral mix.** 1.00 1.00 1.00
Calcium carbonate 1.00 0.50 0.50
Nutient composition
Dry matter (%) 90.30 90.60 90.80
Crude protein (%) 12.03 12.00 12.07
Metabolizable energy (Mcal/kg) 2.03 2.35 2.69
Neutral detergent fiber (%) 40.88 35.90 33.88
Acid detergent fiber (%) 23.38 20.75 18.70
Calcium (%) 0.84 0.84 0.84
Phosphorus (%) 0.45 0.45 0.45 *Magalac Commercial protected fat *٭ Mineral mixture contained (/kg) Dicalcium phosphate 708g; Magnassium
sulphate 86.4 g; Sodium choloride 189.2 g; Ferous sulphate 8.9 g; Manganese sulphate 4.9 g; Zinc sulphate 2.2 g; Copper sulphate 0.3 g; Potassium iodide 87.7 mg; Cobalt choloride 8.9 mg and Sodium selenate 15 mg.
68
Milk production and composition
Buffaloes were hand milked twice daily at 0300 and 1500 h. Milk
production from the morning and evening was weighed and recorded.
The recording of milk production commenced in the adjustment period
(-1 week) prior to bST treatment and continued for three months
(completion of the trial). Milk samples were collected on weekly basis
and representative samples were used to determine fat %, SNF % by
using Gerber and Rapid methods, respectively described by FAO
(1986). Total solids (TS%) and lactose percentage determined
according to the methods described by AOAC (1990). Crude protein
(CP%) was analyzed with Kjeldahl methods according to BSI (1990).
Dry matter intake
The feed consumption data were recoded daily to evaluate
production eff iciency of the experimental groups. Representative
samples of TMR and orts were analyzed weekly for proximate analysis
according to AOAC, (2001) and the cell wall constituents (NDF% and
ADF%) were analysed according to the procedures described by Van
Soest et al. (1991). The gross energy of the TMR was determined
through the IKA C-2000 Bomb Calorimeter, while metabolizable energy
(M.E) was calculated as 63% of the gross energy (Mandal et al. , 2003).
The analysis was done in Laboratories of Food and Nutrition
Department, University of Veterinary and Animal Sciences, Lahore.
Feed eff iciency of the experimental rations was determined with the
help of following formula
Feed eff iciency = milk produced (kg) / dry matter intake (DMI)
69
The body weights of the experimental animals were regularly recorded
at fortnightly interval using weighbridge available at the farm.
Statistical Analysis
Data obtained on milk production, milk composit ion (fat, SNF,
total solids, milk protein, ash and lactose), DMI, feed eff iciency,
weight gain and nutrient intake were statistically analyzed using
MINITAB software package of statistical analysis following completely
randomized design (CRD). Tukey’s signif icance difference test was
applied to compare the difference between the treatment means. The
statistical model used for all parameters was
Ỵij = µ + tj + єij
Where
µ = Over all means
tj= Effect of treatments ( 1, 2, 3)
єi j = Difference within treatments means
70
RESULTS AND DISCUSSION
Milk production
The average daily milk yields of the animals fed either a low
energy density (LED), medium energy density (MED) or high energy
density (HED) and treated with bST was 7.90, 8.16 and 8.88 kg/d,
respectively (Table 3). The weekly milk production trend of the three
treatment groups is shown in Figure 1. The average daily milk yield of
animals fed HED ration was signif icantly higher (P<0.05) than other
rations but the difference was non signif icant (P>0.05) between MED
and LED. The increase in milk yield of HED group was due to the
effect of their higher energy intake since the dietary protein level and
management was the same for all three groups. Lormore et al. (1990)
and McGuffey et al. (1990) reported that administration of bST causes
a shift in partioning of available energy towards milk yield at the
expense of body tissue, so that an energy dense diet may be needed.
Contrary to the present f indings Hemken et al. (1991) reported that
feeding bST-treated dairy cows a diet higher in energy than NRC
recommendation had no signif icant impact on milk yield. Also, contrary
to the f indings of the present study Tarazon-Herrera et al. (2000) found
that milk yield response was greater for bST-treated cows fed a low
rather than a high-energy diet. Difference may be attributed to stage of
lactation.
71
0.00
2.00
4.00
6.00
8.00
10.00
12.00
1 2 3 4 5 6 7 8 9 10 11 12
Milk
yie
ld (
kg/d
)
Weeks
LED
MED
HED
Figure 1 Trend of milk production in animals given low, medium and
high-energy diets.
Milk composition
The average milk fat, SNF, total solids, protein and lactose percent are
shown in Table 3. The energy density of the diet had no effect (P>0.05) on
any of these parameters. Bauman, (1989) found that bST treatment did not
affect milk composit ion due to the homeorhetic control involved in the
metabolism of lipid, carbohydrates and amino acids. The results of present
study are also consistent with previous f indings of Terrazon-Herraera et al.
(2000) who did not record any effect of bST administration on milk
composition (SNF, fat, protein and lactose) in western dairy cows with
varying level of dietary energy.
72
Table 3.
Effect of bovine somatotropic hormone administration on productive performance in lactating Nil i- Ravi buffaloes fed varying levels of dietary energy (mean± SE)
Variables LED (+ bST)
MED (+ bST)
HED (+ bST)
Milk production (kg/d) 7.90 ± 0.11 a 8.16 ± 0.06ab 8.88 ± 0.0.20 c
Milk composit ion (%) Fat
SNF
TS
CP
Lactose
7.00 ± 0.12 9.02 ± 0.12 16.07 ± 0.03 3.35 ± 0.05 4.65 ± 0.08
6.46 ± 0.16 8.94 ± 0.09 15.40 ± 0.09 3.27 ± 0. 10 4.63± 0.08
7.09 ± 0.13 8.95 ± 0.09 16.05 ± 0.08 3.24 ± 0.07 4.86 ± 0.09
Body weight gain (kg) 5.75 ± 0.64 4.75 ± 1.10 5.00 ± 1.08
Feed eff iciency (kg of milk yield/ DMI)
0.61 ± 0.01a 0.66 ± 0.01b 0.74± 0.01c
Means with different superscripts in a row differ significantly (P< 0.05) bST = bovine somatotropic hormone Fat= crude fat SNF = solid not fat TS = total solid CP = crude protein
Body weight change
The average weight gain over the tr ial period on ration LED,
MED and HED was 5.75, 4.75 and 5.00 kg, respectively (Table 3) and
these did not differ signif icantly (P>0.05). Srinivasa-Rao and
Rangandham (2000) and Jorge et al. (2002) found that body weights
were not affected on administering bST to buffaloes, whilst Huber et al.
73
(1997) found that body weights were increased up to 37% in cows
injected with bST for four consecutive lactations. However, Moallem et
al.(2001) observed a decrease in body weights in dairy cows despite an
increased DMI after bST treatment.
Feed intake and feed efficiency
There was a signif icant decrease (P<0.05) in DMI as the energy
density of the diet increased (Table 4). However, there was a
concomitant improvement in average feed eff iciencies (milk yield/kg
DMI); 0.61, 0.66 and 0.74 for LED, MED and HED, respectively (Table
3 and Figure 2). The improvement in feed eff iciency with energy
density of the diet was l inear; with an improvement (P<0.05) of 8.2 and
21.3% for MED and HED groups, respectively compared to LED.
Chill iard (1989) suggested that the magnitude of increase in feed intake
depends upon milk yield and energy density of diet. Results of this
study indicate that feed intake increases as energy density of the diet
decreases Lormore et al. (1990) and Drackley et al. (2003) also found
feed eff iciency was improved in bST-treated dairy cows fed a high-
density ration. This was achieved by altering the nutrient in a manner
that provides the mammary glands increased access to substrate
supplies that may be uti l ized for milk production rather than increasing
adipose tissue store. Bauman et al. (1992) and Chalupa et al. (1989)
observed that daily nutrient requirements were increased by an amount
equal to the increase in milk, and productive eff iciency (milk per unit
of feed) was improved because a greater proportion of the nutrient
intake was used for milk synthesis.
74
0.610.66
0.74
0.00
0.10
0.20
0.30
0.40
0.50
0.60
0.70
0.80M
ilk y
ield
/ D
MI
LED MED HED
Dietary groups
Figure 2. Average feed eff iciency of bST-treated Nil i-Ravi buffaloes
fed low, medium and high energy density rations
Nutrients intake
The average daily nutrient intakes (crude protein, NDF, ADF,
ether extract and Ash) are shown in Table 4. As the energy density of
the diet decreased, individual nutrient intakes (with the exception of
ether extract fraction) increased (P<0.05). This was to overcome the
energy requirements in response to increasing milk yield with bST
because the magnitude of increase in DMI depends upon the response in
milk yield, the method of bST administration and the energy density of
the diet (Chil l iard, 1989). Bauman et al. (1985), Moallem et al. (2000)
and Helal and Lasheen, (2008) concluded that DMI increased linearly
as milk production increased when animals are injected with bST. This
increase in nutrients may be attributed to the homeorhetic regulation of
bST. Results of the present study however, indicate that responses in
75
DMI will be modif ied by the energy density of the diet being fed to the
animals being administered bST.
Table 4.
Effect of bovine somatotropic hormone administration on daily nutrient intake of in Nil i Ravi buffaloes fed varying level of dietary energy (mean ± SE)
Variables LED (+ bST)
MED (+ bST)
HED (+ bST)
Dry matter intake (kg/d) 11.67 ± 0.06 a 11.17 ± 0.11b 10.85 ± 0.06c
Crude protein (kg/d) 1.40 ± 0.01a 1.34± 0.01b 1.30± 0.04 c
Neutral detergent f iber
(kg/d) 4.77 ± 0.02a 4.00 ± 0.04b 3.73 ± 0.06
Acid detergent f iber
(kg/d) 2.70 ± 0.01a 2.30 ± 0.02 b 2.02 ± 0.01c
Ether extract (kg/d) 0.37 ± 0.06a 0.39 ± 0.01 b 0.46± 0.01 c
Ash (kg/d) 1.56 ± 0.01a 1.55 ± 0.01b 1.27 ± 0.00c
Means within a row bearing different superscripts differ signif icantly (P<0.05) DM = dry matter CP = crude protein, NDF= neutral detergent f iber ADF = acid detergent fiber EE = ether extract.
76
CHAPTER-5 Publication 1
Effect of bovine somatotropic hormone on the
productive performance of Nili-Ravi buffaloes
M.A. Jabbar1, I. Ahmad1, S. Javid2, M.A. Chaudhry2, R.H. Usmani3 1 Department of Animal Nutrition, University of Veterinary and Animal Sciences,
Lahore, Pakistan 2 Livestock Production Research Institute, Bahadurnagar, Okara
3 Pakistan Agriculture Research Council, Islamabad Corresponding author M.A. Jabbar. Department of Animal Nutrition University of Veterinary and Animal Sciences, Lahore, Pakistan - Tel. +92-42-7236374 - Email [email protected]
ABSTRACT The study was conducted on 21 Nili-Ravi lactating buffaloes with similar milk production and stage of lactation. They were randomly divided into three groups A, B and C with 7 animals in each group. The group A was injected with full dose of bST hormone (250 mg/animal) with trade name of Boostin-250 at an interval of 14 days, while animals in group B were given injection on alternate days with divided dose of 36 mg/animal. The group C was kept as control. The duration of study was 5 months and the animals were kept on green fodder supplemented with concentrate ration @ half of milk production. The concentrate ration had 17.2% CP and 72.0% TDN. The milk production was 8.06 ± 1.49, 7.85 ± 1.08 and 6.81 ± 1.80 liter in respective groups. The milk production increased by 18.35% and 15.27% in group A and B compared with group C (control). However, the increase was statistically non-significant (P>0.05). The difference in Fat, SNF, and TS percent was nonsignificant among the groups. The service period and services per conception were improved in both the treated groups. The body weight in sub-group A, B and C were similar and none of them lost weight over the study period. The difference among hematological and biochemical parameters was also non-significant.
Key words Bovine Somatotropic hormone, Nili-Ravi buffaloes, Milk production, Reproduction.
INTRODUCTION
With the increase in demand of foods for the ever-growing human population, there is a need to increase the livestock productivity. Feed is a major cost in the Production, which accounts for 60-65% of the total production cost. Hence new technologies are required to attain greater feed efficiency. Bovine somatotropic hormone is one of the first potential biotechnology products in animal production, which improves productive efficiency (Bauman, 1992). Ital.J.anIm.Sci. 6, (Suppl. 2), 1039-1042, 2007 1039
77
VIII World Buffalo congress
In dairy cattle use of bST resulted in 12-25% improvement in milk yield and 5 to 15% feed efficiency with out any substantial alteration in the composition of milk (Burton et al., 1994). Bovine somatotropin reduces the proportion of maintenance requirement out of total nutrient intake (Bauman et al., 1989). Buffalo is the main dairy animal in Pakistan. In spite of large number and good adaptabilility, per animal is very low as compare to Western dairy cattle breeds. Usmani et al. (1991) reported that increased milk production in buffaloes with (bST) is cost effective and harmless and is good contribution towards the milk production. Most of available information’s on buffalo are based on short-term studies. Present study was planned to determine the effect of long-term use of bST on productive, reproductive, physiological / biochemical parameters in Nili-Ravi buffaloes.
MATERIAL AND METHOD S
For the study twenty-one multiparous lactating Nili-Ravi buffaloes with similar stage of lactation and production were selected and kept at Livestock Experiment Station Bahadurnagar, Okara. They were randomly divided into three groups A, B and C. The group A was treated with (bST) hormone with trade name of Boostin-250 manufactured by LG Life Sciences, Ltd. South Korea, at 14 days interval with full dose of 250 mg. Group B was injected at alternate day at divided dose of 36mg/day whereas group C was control (without bST). The research trial continued for five months. The experimental animals were fed green fodders and concentrates. The maintenance requirement of the animals was met by available green fodder of 10% of body weight while production requirements were met through concentrate ration with 17.1% CP and 72.15 TDN. The following parameters were studied 1 Milk production and composition Milk production of individual animals of both groups was recorded daily at the morning and evening milking while milk samples was collected individually on weekly basis. Milk samples were analyzed for Fat, Solids Not Fat (SNF) and Total Solids (TS) percentage through method described by Aggarwala and Sharma, (1961). 2. Feed consumption and body weight Body weights were recorded on monthly basis. Weighed quantities of concentrate ration and fodder were offered to animals. Feed and fodder samples were collected on weekly basis and analyzed for proximate analysis (AOAC, 1995). 3. Reproductive Parameters For reproductive performance data on postpartum estrous, length of estrous period/ (days open) and no of services per conception were recorded. 4. Physiological and Biochemical parameters Blood samples were collected on fortnightly basis and were analyzed for the hematological and biochemical parameters given in Table 1. The data obtained on various parameters were subjected to statistical analysis by using complete randomized design. Duncan’s multiple range test was applied to compare the difference between the means (Steel et al., 1997).
1040 Ital.j.anim.Sci.vol. 6, (Suppl. 2), 1039-1042, 200
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VIII World Buffalo congress
RESULTS AND CONCLUSIONS
Milk production The average milk production of groups A, B and C were 8.06 ± 1.49, 7.85 ± 1.08 and 6.81 ± 1.80 liters, respectively. The increase in milk production was 18.35 and 15.27% compared with group C (control) but statistical analysis revealed that the difference was non-significant. The results of the present study are in agreement with the findings of Jorge et al., (2002), Mishra and Shukla (2004) who found that the increase was 14.93 to 32.4% in treated Murrah and Kundi buffaloes but increase depended on dose rate of bST. Milk composition The average Fat, SNF and TS percentage of the group A, B and C was 6.62 ± 0.21, 6.67 ± 0.07, and 6.54 ± 0.07; 9.25 ± 0.28, 9.33 ± 0.13 and 9.11 ± 0.11; 15.90 ± 0.48, 16.04 ± 0.13 and 16.10 ± 0.85 percent, respectively. Slight increase was observed in milk contents of treated animals over the control but statistical analysis revealed that there was no significant difference. The results of study were similar to the results of Jorge et al., (2002) and Mishra and Shukla (2004) who reported that bovine samototropin did not influence milk composition of dairy cows, Murrah and Kundi buffaloes. The results differed from the findings of Huber et al., (1997) who reported that fat percent decreased in dairy cows with long term use of bST hormone. Body weights The average body weights in groups A, B and C were 537.19 ± 50.89, 550.62 ± 89.43 and 528.30± 30.80 kg, respectively. There was non-significant difference in body weights of bST treated groups than control. The results of the study were similar to the results of Srinivasa-Rao and Ranganadham (2000) who found that body weights were not affected by supplementation of bovine somtotropin. Results of present study differed from Huber et al., (1997) who found that body weights were enhanced up to 37% in cows injected with bST for four conescutive lactations. Reproductive performance The service period was 71.4, 67.33 and 112.36 day while services per conception were 1.2, 1.16 and 1.58 in group A, B and C, respectively. Apparently it was found that there was improvement in reproductive parameters in buffaloes receiving bST. The results of the study are supported by the findings of Dahoo et al., (2003) who found no adverse effect of bST on reproductive performance in dairy cows rather some measures tended to improve with bST. Blood metabolites The means haematological and biochemical values of the control and treated animals are shown in Table 1. All such parameters did not vary (P > 0.05) among experimental groups. The results of study are similar to the results of Kweon (2000) who concluded that bST had no effect on hematological and biochemical values of the dairy animals.
Ital.j.anim.Sci.vol. 6, (Suppl. 2), 1039-1042, 2007 1041
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VIII World Buffalo congress
Table 1. Mean (± S.D.) values of different haematological and
biochemical para-meters. Parameters Group –A Group-B Group-C
ESR mm (Ist h) 64.15 ± 7.93 55.15 ± 29.03 62.59 ± 19.05
Haemetocrit value% 32.0 ± 3.59 32.37 ± 2.30 31.96 ±1.70
Glucose mg /dl 56.36 ± 3.05 55.49 ± 4.62 57.27±2.32
Haemoglobin mg /dl 11.43 ± 0.62 11.85 ± 0.34 12.04 ± 0.53
Total protein mg /dl 7.67 ± 0.43 7.96 ± 0.38 7.49 ± 0.36
Cholestrol mg /dl 173.90 ± 34.9 175.90 ± 17.4 185.12 ±14.1
Urea mg /dl 3.79 ± 0.36 3.85 ± 0.12 3.92 ± 0.29
Calcium mg /dl 9.54 ± 1.32 9.23 ± 1.30 9.63 ± 1.16
Sodium meq / liter 177.31 ± 30.1 165.29 ± 28.2 177.39 ± 30.2
Potassium meq / liter 36.48± 4.52 34.22 ± 6.85 35.81 ± 5.70
REFERENCES - Aggarwala, A.C. and Sharma, R.H. 1961. A laboratory manual of
milk inspection. 4th ed. Asia Publishing House London. AOAC. 1995. Offcial
Methods of Analysis. 15th ed. Association of Analytical Chemists, Arlington,
Virginia, USA. Bauman, D.E. (1992) Bovine somatotropin review of an emerging
animal technology. J. Dairy Sci.75 3432-3451. Bauman, D. E., Hart, D.L. Crooker,
B.A., Partridge, M.S., Garrick, K. D., Sandles, K., Erb, H.N., Franson, S.E., Hrtnell,
G.F.and Hintz, R.L 1989. Long-term evaluation of prolonged-release formulation of
N-methionyl bovine somatotropin in lactating dairy cows. J. Dairy Sci. 72 642.
Burton, J.L., Block, E., Glimm. R., 1994. A review of bovine growth hormone. Can.
J. Anim. Sci.74 167-201. Dohoo, I.R, DesCoteaux, L., Leslie, K., Fredeen, A.,
Shewfelt, W. and Preston, A., 2003. A meta analysis review of the effects of recombinant
bovine somatotropin. 2. Effects on animal health, reproductive performance, and culling.
Can. J. Vet. Res. 67 252-64. Huber, J. T., Fontes, JR. Z. WU. C., Sullivan, J. L., Hoffman,
R. G. and Hartnell, G. F., 1997. Administration of recombinant bovine somatotropin to dairy
cows for four consecutive lactations, J Dairy Sci 802355-2360. Jorge, M.A., Gomes,
M.I.F.V. and Halt, R.C., 2002.
1042 Ital.j.anim.Sci.vol. 6, (Suppl. 2), 1039-1042, 2007
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VIII World Buffalo congress
Effect of recombinant bovine somatotropin (bST) utilization on milk production from
buffaloes. R. Bras Zootec. 31 213-222. Kweon, U.G.K.T., Nam, H.S., Kim, S.K., Yun, J. S.
and. Hang, B. J., 2000. Effect of recombinant bovine somatotrpic hormone injection time on
haemotological values and blood metabolic substrates in Holstein steers. Kor .J. Anim. Sci.
42 269-278. Mishra, A. and Shukla, D. C., 2004. Effect of Recombinant Bovine
Somatotropin (Boostin-250) on blood metabolites and milk yield of lactating buffaloes.
Asian-Aust. J. Anim. Sci. 17 1232-1235. Srinivasa-Rao, K. and Ranganadham, M., 2000.
Effect of bovine somatotropin on milk production and composition in lactating Murrah
buffaloes. Indian J. Dairy Sci. 53 46-50. Steel, R.G.D., Torrie, J.H and Dickey,. D.A., 1997.
Principles and procedures of statistics. A biochemical approach (3rd ed.) McGraw Hill Book
Co. Inc., New York, USA. Usmani, R.U., Khan, A.G. and Author, I.H., 1991. A review of
growth hormone biotechnology for increased milk production. Pakistan.Vet.J.11 100.
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CHAPTER-5 Publication 2
Short communication
PERFORMANCE OF LACTATING BUFFALOES ADMINISTERED BOVINE SOMATOTROPIN HORMONE
I. Ahmad, M. A. Jabbar1, T. N. Pasha and M. Abdullah2 Department of Animal Nutrition
University of Veterinary and Animal Sciences, Lahore-5400, Pakistan (Received 12 July, 2006)
ABSTRACT Nili-Ravi buffaloes (14; 476.9t57.2 kg BW; 8.88t0.98 1 milk/d; 90t6.5 days in milk) randomly divided into two equal groups. Animals in both the groups were offered conventional TMR, while animals in 2nd group were injected bovine somatotropin (bST) hormone (250 mg/animal) at an interval of 14 days for 60 days. The milk production was increased by 7.0% in bST group over that of control group and the increase was statistically non-significant. However, the feed efficiency for milk production was improved (P< 0.05) in treated group. The milk composition, body weight gain and digestibility of nutrients were similar in both groups. It was concluded that there was no effect of administering bST hormone @ 250mg/animal on milk yield and its composition in buffaloes. (Indian J. Anim. Nutr. 2007, 24(1) 5254)
Key words Bovine somatotropin, Milk production, Feed efficiency, Buffaloes
Bovine somatotropin improves the
productive efficiency specially milk yield per unit of feed input. In dairy cattle, use of bST resulted in 12-25% improvement in milk yield and 5 to 15% feed efficiency without any substantial alteration in the composition of milk (Ludri et al., 1989; Rose et al., 2004). The higher productive response was attributed to increased synthesis of lactose, fat and pro-tein in mammary glands (Bauman et al., 1988). There is not much information available about use of bST hormone in buffaloes. The present experiment was conducted to study effect of bST on feed efficiency in lactating buffaloes.
Nili-Ravi buffaloes (14; 476.9 to 57.2 kg BW; 8.88to.98 kg/d milk yield and 90t6.5 days in milk) randomly divided in to two equal groups. Animals in both the groups were offered conventional TMR, while animals in 2nd group were injected recombinant bovine somatotropic hormone (bST) @ 250 mg/animal (Boostin -250) at fortnightly interval for 60 days.
Total mixed ration (maize grain 9.0, rice polish 8.0, wheat bran 7.0, cotton seed cake 10.0, cotton seed meal 2.0, maize gluten (30%) 13.0, rape seed meal 7.0, rice straw 30.0, molasses 12.0, mineral mixture 2.0%) containing 12.5% CP and 65.0% TDN (NRC, 2001) was offered.
Table 1. Intake and digestibility of nutrients in buffaloes administered bovine somatotropic hormone
Parameters TMR TMR-bST
Pooled SE
DM intake % BW 2.3 2.4 0.9 Digestibility of nutrients, %
DM 67.3 71.6 0.9 CP 65.0 66.3 1.5 CF 76.7 77.4 1.0 EE 75.5 75.9 1.5 Ash 71.3 71.1 0.7
1Corresponding author E-mail: [email protected]; 2Department of Livestock Production
82
Effect of bovine somatotropin on the performance of buffaloes
. The experimental animals in both the groups were fed available green fodder @5 kg/animal/d to fulfill the requirement of vitamin A. Milk yield was recorded daily while milk samples were analyzed for Fat, SNF and TS weekly (Aggarwala and Sharma, 1961). Feed samples were analyzed for proximate principles (AOAC, 1990), and feed consumption data were recorded. During the last week of study a digestibility trial on 3 animals from each group was conducted. Representative feed and fecal samples were collected and analysed. Data was statistically analyzed by using t-test (Steel et al., 1997). There was no difference in the digestibility of nutrients in the two groups (Table 1), confirming the earlier report in cows (Santos et al., 1999). However, Newbold et al., (1997) reported that digestibility of nutrients was increased in bST treated animals.
The daily milk yield of groups A and B was 8.25 and 8.80 kg respectively (Table 2), Milk production increased by 7% in group B over that of group A though the difference was non significant. Contrary to the finding of the present study, increased milk production has been reported in many studies on administration of bST hormone. Jorge et al., (2002) observed 32.8% increase with 4% FCM yield in Murrah buffaloes when injected with 500 mg of bST/animal after 14 day interval. Relatively higher increase could be due to higher dosage level used in studies. The average milk fat, SNF, TS and protein percent of both the groups were similar (Table 2). The results of study were similar to those of Mishra and Shukla, (2004) who also did not record any effect of bST administration on milk composition in western dairy cows and Kundi buffaloes.
There was no difference in body weight gain of both groups. The results of the study were similar to the results of Jorge et al., (2002), but Huber et al., (1997) reported that body weights were increased up to 37% in cows injected with bST for four consecutive lactations.
Table 2. Performance of buffaloes on bST administration.
Parameters TMR TMR-bST
Pooled SE
Milk yield, kg/d 8.3 8.8 0.50 Milk composition,
%
Fat 6.7 6.9 0.04 SNF 9.1 9.2 0.10 TS 15.7 16.1 0.20 Protein 3.6 3.7 0.04 Cain in BW, kg 12.9 14.3 14.30 FC, kg/d 12.2 12.4 0.04 PCE 1.5a 1.4b 0.01
Figures with different superscripts in a row differ sig-nificantly, P<O.05; FC - Feed Consumed; FCE-Feed conversion efficiency, kg/kg milk yield
The feed efficiency was significantly improved (P<0.05) in bST treated group confirming the earlier report (Annexstad et al., 1990). It was con-cluded that there was no effect of administration of bST @250mg /animal on milk yield and its composition in Nili-Ravi buffaloes.
REFERENCES
Aggarwala, A. C. and Sharma, R. H. (1961) A laboratory manual of milk inspection. 4th ed. Asia publishing house London.
Annexstad, R. J., Oiterby, D. E., Linn, J. G, Hanse, W. P., Soderholm, C. G and Wheatstone, J. E. (1990) Somatotropin treatment for consecutive lactations. J. Dairy Sci.. 73 2423-2436.
AOAC. (1990) Offcial Methods of Analysis. 15th ed. Association of Analytical Chemists, Arlington, Virginia, USA
Bauman, D. E., Peel, C. J., Steinhour, W. D., Reynolds, P. 1., Tyrell, H. E, Brown, A. C. G and Haland G. L. (1988) Effect of bovine somatotropin on metabolism lactating dairy cows Influence on rates of irreversible loss and oxidation of glucose and non-esterified fatty ac-ids. J. Nutr., 18 1031-1040.
Huber, J. T., W. U., Z., C. Fontes, J. R., Sullivan, L., Boffman, R O. and Hartnell, O. E. (1997) Administration of recombinant bovine somatotropin to dairy cows in four consecutive lac-tations. J. Dairy Sci., 80 2355-2360.
Jorge M. A., Gomes M. I. E. V. and Halt, Re. (2002). Effect of recombinant bovine somatotropin (bST) utilization on milk production from buffaloes. R. Bras Zootec., 31 213-222.
Ludri, R. S., Upadhyay, R. C., Singh, M., Guneratne, J. R. and Basson R. P. (1989). Milk production in lactating buffaloes receiving recombinantly produced bovine somatotropin. J. Dairy Sci., 72 2283-2287.
83
Newbold, J., Heap, A. R. B., Prosser, E. G, Pipps, R. H., Adrianes, E. and Hard. D. L. (1997). The effect of bovine somatotropin and diet on somatotropin binding sites in hepatictissue of lactating dairy cows. J. Dairy Sci., 80 10851091.
NRC (2001) Nutrient Requirements of Dairy Cattle. 7th revised edition, National Academy Press, National Research Council. Washington, DC. pp.147.
Rose, M. T., Weekes, T. E. C. and Rowlinson, P. (2004) Individual variation in the milk yield response to bovine somatotropin in dairy cows. J. Dairy Sci., 87 2024-2031.
Mishra, A. and Shukla, D.C. (2004) Effect of recombinant bovine somatotropin (Boostin-250) on blood metabolites and milk yield of lactating buffaloes. Asian-Aust. J. Anim. Sci., 17 1232-1235.
Santos, J. E. P., Huber, J. T., Theurer, C. B., Nussio, L. G., Nussio, C. B., Tarazon, M. and LimaFilho, R. O. (1999) Performance and nutrient digestibility by dairy cows treated with bovine somatotropin and fed diets with steam-flaked sorghum or steam-rolled com during early lactation. J. Dairy Sci., 82 404-411.
Steel, R. G. D., J. H. Torrie and D. A. Dickey (1997) Principles and procedures of statistics. A Biochemical Approach (3nded.) McGraw Hill Book Co.Inc., New York, USA
84
Chapter-6
SUMMARY
Use of bovine somatotropic hormone (bST) for increased milk
production has been widely investigated in dairy cattle, whereas very
lit t le work has been done in buffaloes. To observe the effect of bST on
buffalo for long term duration study was planned with the objectives to
investigate the effects of long term use of bST on milk production, milk
composition, reproduction, hematological and biochemical parameters
in Nili-Ravi buffaloes. For this study 30 lactating Nili-Ravi buffaloes
with similar milk production and stage of lactation were selected and
randomly divided in to two groups A and B with 15 animals in each
group. The group A (0 bST) served as control while animals in group B
(+bST) were given injection of bST (250 mg Boostin-250/animal) at
14d interval. Nutritional requirements of experimental animals were
met through available green fodder (45-50kg/day) supplemented with
concentrate ration @ half of milk production. The milk production was
signif icantly (P<0.05) increased by 18.04 % in treated group compared
with control. The results showed that there was no signif icantly
variations in parameters like milk composit ion, dry period and lactation
length, calving interval in both the groups. The postpartum estrous
period and service period were signif icantly (P< 0.05) improved which
reflected positive effect of bST on reproductive parameters. However,
the difference in services per conception was non-signif icant. Small
variations were found in the prevalence of contagious and non
contagious diseases in both experimental groups during the study
period. The differences among body weights, hematological and
biochemical parameters were also non-signif icant expect blood urea
85
nitrogen (p< 0.05). The proceeds over a lactation period of 305 days
was PKR. 4227.0 with the use of bST.
Second tr ial was conducted to study the effect of dose interval of
bST in Nili-Ravi buffaloes. For the proposed study 21 Nili-Ravi
lactating buffaloes with similar milk production and stage of lactation
were randomly divided into three groups A, B and C with 7 animals in
each group. The group A was injected with full dose of bST hormone
(250 mg/animal) with trade name of Boostin-250 at an interval of 14
days, while animals in group B were given injection on alternate days
with divided dose of 36 mg/animal. Group C was kept as control.
Duration of study was 5 months and the animals were kept on green
fodder supplemented with concentrate ration @ half of milk production.
The concentrate ration had 17.2% CP and 72.0% TDN. The milk
production increased by 18.35% and 15.27% in-group A and B
compared with group C (control) but increase was non-signif icant
(P>0.05) . Similarly data revealed that dose interval had no affect on
milk contents, reproductive and hematological parameters in all the
experimental groups.
In a third trial feed digestibi l i ty and eff iciency for milk
production was studied. For the study fourteen Nili-Ravi buffaloes at
their mid lactation with almost same level of milk production were
randomly divided into two groups A and B with seven animals in each
group. The group A was kept as control, while group B was injected
bST hormone (250 mg/animal) at an interval of 14 days and continued
for 60 days. The nutritional requirements of animals in both the groups
were met through TMR according to NRC recommendations. The milk
production was increased by 7.0% in treated group (B) as compared
with control group (A) and the increase was statistically non-signif icant
86
(P>0.05). However, the feed eff iciency for milk production was
signif icantly improved (P< 0.05) in treated group. The differences in
milk composition (Fat, SNF, TS and Protein percent) body weight gain
digestibi l ity of dry matter and other nutrients in treated and control
groups were found non-signif icant (P>0.05).
The fourth trial was conducted to determine the effect of energy
on milk production and its quality under the influence of bST hormone
in Nili-Ravi buffaloes. Multiparous (n=12) buffaloes with mid lactation
and similar level of milk yield were selected and randomly divided in
to three groups i.e. A, B and C with four animals in each group. All the
experimental animals were injected bST with trade name of Boostin -
250. The dose level was 250 mg per animal and injection was given at
fortnightly interval during study period. The nutritional requirements
of three groups animals were met through TMR with varying levels of
energy (15% low and 15% above the recommendations of NRC). The
milk yield was signif icantly higher (p<0.05) on medium and high
energy ration but the difference of milk yield was non signif icant
(p>0.05) between medium and low energy diets. The milk components
and body weight gain were similar on all rations, while feed eff iciency
and nutrient intake (except ether extract) in low energy diet was
signif icantly higher (p<0.05) from two other rations. It may be
concluded that 15% higher energy than recommended by NRC favoured
milk production in Nil i Ravi buffaloes when they were injected bST
hormone.
Conclusion
On the over all there was consistency of results for milk
production and milk composition with reference to available l iterature.
However, some reproductive parameters including postpartum estrus
87
and service period were signif icantly improved with the use of bST
hormone. This effect has not been reported in the previous li terature
which needs to be further investigated and verif ied. Similarly the dose
level in buffaloes needs to be further studied.
88
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