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A note on the effects of feeding total mixed rationon performance of dairy goats in late lactation

.ABSfRACTMaltz. E., Silanikove, N.. Karaso, Y.. Shefet, G., Meltzer. A. a:td Bank, M., 1991. A note on WC

effectsof feeding lotal mlxed ration on performance of dai!? goats n late lactation. Afdtn. Feed%!.~T~~llnol.. 5: 15-m.

Feedingdriry goats (Israeli Saanen) in late lactation (last trimester) a 10131mixed ration (TMR ),OFa combination of TMR and scparaw concentr-xes :md hay. or a separate feeding of concenlratesand a high-quality hay uas cwnpared. Iliet sP:ectivify was appreciable with goats fed concentratesand hay separately, whereas there was no ;;lectivity with TMR. Daily milk yield. milk fat, proteinproduction and feed conversion ratio (kg feed kg- milk) in goats fed TMR was equal to 01 betterthan those recorded in the control an< the combmed regime. It was concluded that, in Ierms of dietutilization, the TMR feeding systemwas ruperior to feedmg the different componentsseparalcly.

INTRODUCTION

The common practice for feeding goats in Israel is to give fixed amounts ofconcentrates and free access to high-quality hay (usually alfalfa). This resultsin ayproximately a 60% concentrates-40% forage ration. As the quality of theration is high, it is considered adequate compared with nutritional standards(Haenlein, 1978). However, compared with common dairy cattle rations, itis more expensive in spite of containing a similar ratio of concentrates lo for-age. Dairy cattle feeding in Israel is based almost exclusively on feeding theanimal with a total mixed ration (TMR). In addition to the nutritional ad-vantages of feeding TMR (Holter et al., 1977; Phipps et al., 1984; Nocek etal., 1986), it is flexible and allows the use of agricultural by-products (e.g.cotton seeds and citrus pulp) with silage and hay. Goats are frequently veryAuthor to whom correspondence should be addressed.

0377-8401/91/$03.50 Q 1991 Eln vier Science Publisbcis?.V. All rights reserved.


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I6 E. MALTZ ET AL

choosy about the parts of the feedstuffs they eat and particularly about for-ages (Huston, 1978; Morand-Fehr, 198 1). Therefore goat breeders are reluc-tant to use a TMR.The purpose of this study was to examine the feeding to dairy goats of aThlR, and to compare it with the common feeding practice and with a furtherversion of 60% TMR-40% hay and concentrates.MATERIALS AND METHODS

Twelve Saanen goats were used in this study. Two goats in their first andtwo in their second lactation, 6 months post partum, were allocated to eachof three groups (T, PT and C) on the additional basis of milk yield.For 1 month before the experiment, the goats were group fed a fixed amountof concentrates and separately high-quality hay ad libitum (Table I ). Thegoats were machine-milked twice a day at 09:00- IO:00 h and 17:00- 18:Oo h.Goats were weighed once a week. Daily ration allotment and chemical com-position are given in Table 1.Diets were introduced over a 2 week period followed by 4 week data collec-tion; groups T and C received half of the ration after each milking, and groupPT received TMR after the morning milking and hay plus concentrates in theTABLE IDaily ralian components (% of DM offered) and chemical comporitmn (46 of DM)All01lllent Group T

100% TMRGroup PT60% TMR 40%TMR

Group CNoTMR

Wet rilage 27COllCelltIa*eS~ 38Midbloom vetch hay 12Whole cotlon seeds 23tomposition (a)

DM (%)CPCrude fiberCrude fatCrude ashCalcium

78.8916.3919.47

8.876.280.880.4.2

61:39PhosphorusConcentrates: roughage ratio

:: 229 17

IS

81.6516.31I8 I56.907.080.860.43

61:39

88.8216.1815.603.668.19I.160.45

61:39CP lO.7%, crude tiber 24.5%, ash 6.G%.CP 11.496, crude fiber 6.551, ash 6.3%. fat 5.2%, NaCl and vitamin+traceclemcnt concentrate 1%.CP 14.3%, crude fiber 30.18, ash ,,.I%.CP 22.38, crude fiber 28 596, ash 3.8%.


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afternoon. During the experit?ent. each component was offered at about 20%above the reference ad libitum consumption.The TMR was trgshly prepared each day. The hay was chopped into piecesof approximately 2 cm length, tefore being mixed with the other componentsfor 20 min in a horizontal mixer (Davis Sons Meg. Co.). Samples of feedsoffered and refused were taken daily and frozen for further analysis. Feedsamples were composited, sampled, dried and ground to 1 mm size for cellwall (CW) analysis (Goering and Van Soest, 1970). Ration comprrnents wereanalyzed for dry matter (DM), ash, crude protein (CP), crude fat, crudefiber, phosphorus and calcium (Association of Official Analytical Chemists,1975) and the results are presented in Table 1.Individual milk yield of each mi!king was measured daily. Milk samples of

morning and afternoon milkings were taken once a week for analysis of fat,protein and total solids. The samples were kept at 4C for no longer than 24h before analysis. Fat content was measured according to the Gerber method,protein by Kjeldabl analysis, and total solids were determined by drying milksamples at 100C for 4 h.The results are presented as mean values &SD. The paired f-test was ap-plied to compare between pre-experimental and experimental variables. Dif-ferences between treatments were assessed by analysis of co-variance on pro-duction variables using pre-experimental yields as the co-variant.RESULTS

There was no difference in DM consumption between the three groups(Table 2). However, ration selectivity was indicated by higher CW contentin refusals of groups PT and C compared with group T (Table 2).In group C, daily milk yield in all four goats decreased during the experi-ment compared with that of the pre-experimental period (data not shown),TABLE 2

Gr0llp T PT CDM offeri-d (kg)Refusals (kg)Intake2 (kg)Cell wall (I of DMoffered)Cell wall (%of DMrefused)

10.9 10.3 10.42.7tO.4 2.3*0/j 1.6fO.48.2f0.3 8.0fO.4 8.8f0.3

41.5 38.4 33.740. I 58.4 54.4

GroupT, 100% TMR: PT, 60% TMR: C, 0% TMR.2Average and SD of7 days meafumnent in each group.


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18 E.MALi-2ETAL.TABLE 3Mean production (kg) afmilk, fat, protein an d milk LolaIsolids, ofgoat s before t he experimcnl a ndwhen feddiffercnldiets (x?SD)GlOUP Pre-experiment ExperimentalT Mdk vield

Milk iatMilk proteinMilk solids

PT Milk vieldMilk ia tMilk proteinMilksolids

C Milk yleld 2.680*f0.370Milk fat 0.070 io.009Milk prot ein 0.084 +O.OOSMilk solids 0.297f0.040

2.610 f0.4800.073 +0.0080.082 +0.0090.290 +0.0092.540 ?0.6100.069 ?0.0090.085 iO.0080.287*f0.070

2.57OtO.1300.07~+0.0080.080 kO.0050.28811rO.O172.26OiO.2500.C68iO.OOS0.078 ?0.0090.25~?+0.0702.32b+0.2600.069i.0.0090.077 ion07

GroupT. ,OO%TMR; PT ,60%TMR;C,O%TMR.Signin canldifferences wrh in rows (PcO.05).~%gnificant differences within columns (P


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(Table 3 ) . The changes described between groups for milk yield were alsoreflected in 4% fat correct milk fFCM) yield (Table 4). Feed conversionefficiency during the experimental period was similar in groups C and T, andin both was better than in group PT (Table 4). The general trend in bodyweight changes in all groups was a slight increase ( 10 out of 12 goats) duringthe experimental period.DISCUSSION

High selectivity, as evidenced by the differences in CW between feed of-fered and refused, was demonstrated by goats fed a ration of unmixed dietcomponents (groups PT and C, Table 2), but not by goats fed TMR (groupT). The latter also consumed the same amounts of DM as the other two groups,which can be explained by the fact that goats are capable of maintaining highintakes even when consuming large amounts of forage ( Morand-Fehr, 198 1).We observed that refusals of goats in group PT contained a high proportionof the TMR portion, apparently because the goats expected their preferredfeed (concentrates and hay) in the afternoon. Therefore we may concludethat the approach of feeding a combination (group PT) of the traditional(group C) and TMR (group T) systems is inferior to both separately.Milk production was expected to decline, as was indeed found in groups PTand C (Table 3). Feeding TMR not only did not adversely affect milk pro-duction, protein and fat secretion compared with controls, but even slightlyimproved it (Table 3). Group PT, and to a lesser extent, group C, which se-lectively prefer red the more concentrated components of the diet, and whoseconsumption was therefore more energetically dense, did not perform betterthan group T. In fact, the best feed conversecr. ratio was C&d&2? for groupT. It seems that diet utilization was not hampered by the TMR, which is inaccordance with the view that goats are efftcient in digesting fiber (Morand-Fehr, I98 I ) Increases in the proportion of roughage in the diet will increasethe proportion of acetic acid in the rumen, and hence the higher fat contentand total solids yield in group T. Generally, the feed conversions in this workare similar to those cited in other studies (Bhattachatya, 1980; Morand-Fehrand Sauvant, 1980; Maltz et al., 1982).

Results obtained in dairy cattle (Hotter et al., 1977; Phipps et al., 1984;Nocek et al., 1986) showed that feeding TMR is superior to feeding differentcomponents separately in terms of diet utilization. From our results it seemsthat this system may be regarded as an alternative to the common practice forfeeding dairy goats as well.

REFERENCESAssnciati~r?&X?kla:n&dcalChcmists. 975.OffXal MethadsofAnalysis,2thcdn.AOAC.Washington, C.


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20 E. MALTZ ET AL.Bhattacharya, A.N., 1980. Research on goat nutrition and managemenl in Mediterranean, Mid-

dle East and adjacent Arab countries. J. Dairy Sci., 63: 1681-l 700.Cowing, H.K. and Van Soesl, P.J., 1970. Fomge fiber analysis. U.S. Dep. Agric., Agric. RPS,

Serv. Agric. Handh. 379.Haenlein, G.F.W.. 1978. Dairy goatmanagement. J. Dairy Sci., 61: IO1 I-1022.Holler. J.B.. Urban. Jr.. W.E.. Haves. H.H. and Davis. H.A.. 1977. Ulilization of diet comoo-

ncnts fed blended or separat&to lactating cows. J.Dairy Sci., 60: 1288-1293.Huston, J.E., 1978. Forage ulilization and nutrient requremen~s ofthe goat. I. Dairy Sci., 61:

988-993.Maltz, E., Silanikave, N. and Shkolnik, A., 1982. Energy cobt and water requirements of black

Bedouin goats at different levels ofproduction. J. Agric. Sci., 98: 499-504.Morand-Fehr, P., 198 I. Characteristics du companement alimentaire et de la digestion de Ca-

prim. In: P. Morand-Fehr, A. Bourbouse. and M. de Simane (Editors), Nutrition and Sys-tems of Goat Feeding, Vol. I. ITOVIC, INRA, Paris, pp. 2 l-45.

Morand-Fehr, P. and Sauvant, D., 1980. Composition and yield of goat milk as affected bynutrition. I. DairySci.,63: 1671-1680.

Nocek, J.E.. Steele, R.L. and Braund, D.G.. 1986. Performance ofdaiw cows fed forage andgrain separately versus a total mixed ration. I. Dairy Sci., 69: 2140-2i47.

Phipps. R.H., Eiines, J.A.. Weller. R.F. andThomas. J.. 1984. Comoletedietsfordairvcows: theIeffecl of energy concentration and change in energy concen&on of a complete diet in in-take and performance oflactatingdairy cows. J. Agric. Sci., 103: 323-331.

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