Energy requirement for maintenance, growth, pregnancy,

and lactation in ruminants

Vishnu Vardhan Reddy.PTVM/2015-029

Department of Animal nutritionCollege of Veterinary Science, TirupatiSri Venkateswara Veterinary University

Feed energy systems

• Total digestible nutrients (TDN)

• Traditional system to express digestible energy concentration of

feedstuffs

• Basis of TDN are physiological fuel values

• Equivalence in energy units

1 lb TDN = 2000 kcal Digestible Energy

1 kg TDN = 4400 kcal Digestible Energy

Limitations of TDN Limitations with digestion trials

Errors in chemical analyses

Errors in digestibility trials

Low feed intake increases digestibility

DMI at 3x maintenance reduces TDN by 8%

Underestimates or does not include all energy losses in metabolism

• Underestimates energy loss in urine (5%)

• Does not include methane gas

3 – 10% of feed energy

• Does not include:

Work of digestion

Heat of fermentation

Heat of nutrient metabolism

Overestimates the usable energy value of feeds

• Particularly of forages

Caloric systemEnergy units

• Calorie (cal)

Amount of heat required to increase the temperature of 1 gm of water

from 14.5 to 15.5oC

• Kilocalorie (kcal) = 1000 cal

• Megacalorie (Mcal) = 1000 kcal = 1,000,000 cal

• Caloric system subtracts digestion and metabolic losses from the total

energy of a feedstuff

Gross Energy

Fecal Losses Digestible Energy

Urine Losses Gaseous Losses

Heat Increment Losses

Metabolizable Energy

Net Energy

Work of Digestion

Heat of Fermentation

Heat of Nutrient

Metabolism

Maintenance Retained Energy

Growth

Stored EnergyLactation

Caloric system

• Maintenance

• % of total energy requirement

• 25 – 70% in dairy cattle

• 70% in beef cattle

• Components

• Basal metabolic rate

• Activity

• Body temperature regulation

• Pregnancy

• Growth

• Lactation

Energy requirements

For Cattle and Buffalo

Energy required for maintenance

• The quantity of energy required for maintenance is, by definition, that which

promotes energy equilibrium (zero energy balance).

• Energy requirements for maintenance can be calculated from various feeding

standards.

• This quantity can be estimated directly in fed, as opposed to fasted, animals if the

energy content of their food is known and their energy balance can be measured in

feeding trials.

• A similar approach can also be followed in feeding trials in which animals are not kept

in calorimeters.

• The energy requirements for maintenance of cattle published by AFRC

(1993) are based on fasting metabolism (F, MJ/day) and can be

predicted as follows:

F = 0.53

• The fasting metabolism of bulls is considered to be 15 per cent higher

than that of steers and heifers of a similar weight.

• Activity allowance (A, MJ/day) of 0.0071 W and 0.0095 W is included

for growing cattle and dairy cattle, respectively.

• Thus, the NE requirement for maintenance () of a 600 kg dairy cow

would be calculated as follows:

= 0.53 + (0.0095 X 600)

= 42.3 MJ/day

• If the ME content of the cow’s diet was 11.0 MJ/kg DM, the efficiency

of ME utilisation for maintenance (km) would be 0.714 and the ME

requirement for maintenance () would be calculated as follows:

= 42.3/0.714 = 59.2 MJ/day

• In contrast to AFRC (1993), where maintenance requirements are derived

from calorimetric methods, the maintenance requirements of beef cattle

published by NRC (2000) are derived using the comparative slaughter

technique.

• The requirement of beef cattle can be predicted from empty body weight

(EBW) as follows:

= (Where EBW = W X 0.85)

• And in NRC (2001)

=

ICAR standards

• Maintenance energy requirements for indigenous animals vary

between 61 – 104 kcal ME/ in dry cows and between 113 – 160 kcal

ME.

• ICAR (1998) adopted the value of energy requirement for maintenance

to be equivalent to 122 kcal ME/ for both cattle and buffaloes.

• For lactating cow of Brown Swiss X Sahiwal it is 131 kcal ME/.

• For lactating Haryana cows it is 127 kcal ME/.

BW (kg) TDN (kg) ME (Mcal)

200 1.92 6.94

250 2.28 8.24

300 2.62 9.47

350 2.95 10.67

400 3.27 11.82

450 3.58 12.94

500 3.88 14.04

550 4.18 15.10

600 4.47 16.15

650 4.75 17.18

700 5.03 18.19

750 5.31 19.19

800 5.58 20.17

Maintenance modifiers• Breed

– Implications

• Maintenance requirements of breeds with high milk potential are 20% higher than those with low

milk potential and maintenance requirements of Bos indicus breeds are 10% lower than

Bos Taurus

• Match cow breeds to feed resources

Maintenance

Breed Kcal ME/ Mcal/d % of total annual ME

Angus x Hereford

130 14 73

Charolais x 129 15 73Jersey x 145 14.2 71

Simmental x 160 17.9 75

• Sex

Increase requirement by 15% for bulls

• Lactation

Maintenance requirement of lactating cows is 20% higher than dry cows

Implications

• Early weaning of beef cows reduces maintenance energy requirement

– Reduces feed use

– Stimulates reproduction

• Body condition effects

Reflects previous nutrition

= 0.077 x (0.8 + ((CS-1) x 0.05)

Implications

• Can have compensatory gain in growing cattle or reduce feed requirements

of beef cows by restricting nutrition• Temperature

• Adjustment

= (0.0007 x (20-Temp) + 0.077) Mcal/

• Activity allowance (Beef)

Variation

• 10-20% increase in req for good pasture

• 50% increase in req on poor hilly pasture.

= [(0.006 x DMI x (0.9 – TDN)) + (0.05T/(GF + 3))] x w/4.184

Where DMI is in kg/d

TDN is a decimal

T is terrain (1=flat, 1.5=undulating, 2=hilly)

GF is green forage available in metric ton/ha

• Activity allowance (Dairy)Walking

• Adjustment = 0.00045 Mcal /kg BW/horizontal km

Eating

• Adjustment = 0.0012 Mcal /kg BW

• Assumes 60% of diet is pasture

Walking

• Adjustment = 0.006 Mcal /kg BW

• Assumes a hilly pasture is one in which cattle move 200 m of vertical

distance/day

Energy required for pregnancy

• Very inefficient utilization of energy (14 to 16%)

• Increase energy requirement drastically during last trimester of gestation

• Calculations:

Beef

, kcal/d = 0.576 birth wt (0.4504 – 0.000766t)

Dairy

, Mcal/d = [(0.00318 x t - 0.0352) x (birth wt/45)]/0.218

ICAR standards

• After six months of pregnancy, the growth of fetus increases

significantly.

• The fallowing equation is used to calculate the required energy based

on no of days of pregnancy:

ME (M cal/d) = [(0.00318 X D – 0.0352) X (CBW/45)]/0.14

D = days of pregnancy between 190 and 297

Pregnancy requirements of buffalo/dayMonth of pregnancy DM (kg) TDN (kg) ME (Mcal)

6 – 7 1.0 0.8 2.76

7 – 8 1.2 0.9 3.21

8 – 9 1.4 1.0 3.66

9 - 10 1.5 1.1 4.11

Pregnancy requirements of cattle/dayMonth of pregnancy DM (kg) TDN (kg) ME (Mcal)

6 – 7 0.85 0.64 2.30

7 – 8 0.99 0.74 2.67

8 – 9 1.13 0.84 3.05

Feeding calf

Age (days) BW (kg) ADG (kg) TDN (g) ME (Mcal)

0 – 15 25 200 400 1.5

16 – 30 30 300 500 1.7

30 – 60 40 300 800 2.4

60 - 90 50 350 1000 3.6

B.Wt. (kg) Age (days) Colostrum Milk (kg)

UP to 30 0 – 4 1//10 th BW -

UP to 30 5 – 30 - 1/10 th BW

31- 60 - - 1/20 th BW

Energy required for lactation

• Energy requirements for lactation involve an estimate of the gross energy value () of the

milk, which may be used along with the yield to estimate the net energy requirement for

milk production.

• Determination of the gross energy of milk involves either bomb calorimetry or a detailed

chemical analysis; the amounts of fat, lactose and protein are then multiplied by their

energy values and the products summed.

• The following equation based on the fat content of the milk can be used to calculate the

energy content:

(MJ/kg) = 1.509 + 0.0406F

F is fat content (g/kg).

• More accurate assessments may be obtained by including protein (P)

or protein and lactose (L) (both g/kg) in the prediction equation:

(MJ/kg) = 0.0376F + 0.0209P + 0.948

(MJ/kg) = 0.0384F + 0.0223P + 0.0199L - 0.108

(Mcal/kg) = 0.0929F + 0.0547P + 0.192

• Equal efficiency to maintenance

requirement for lactation, Mcal/day = kg milk/day x (0.0929 x % milk

fat) + (0.0547 x % milk protein/0.93) + (0.0395 x % lactose)

• Simply add to needed for maintenance.

• In case of first lactation give additional 20% of maintenance energy and

10% in second lactation.

• Animal may loose it’s body weight on it’s peak milk yield.

• Energy from body tissue loss (5-point BCS scale)

Body condition score Mcal /kg BW loss

2 3.83

2.5 4.29

3 4.68

3.5 5.10

4 5.57

Energy requirements for milk production/kg in cattle

Fat % DM (kg) TDN (kg) ME (Mcal)

3 0.450 0.290 1.05

4 0.510 0.330 1.20

5 0.570 0.370 1.34

6 0.640 0.410 1.50

7 0.700 0.460 1.64

Energy requirements for milk production/kg in buffalo

Fat % DM (kg) TDN (kg) ME (Mcal)

4 0.550 0.360 1.29

5 0.610 0.400 1.43

6 0.670 0.440 1.58

7 0.740 0.480 1.73

8 0.800 0.520 1.88

9 0.860 0.560 2.02

10 0.930 0.600 2.17

Energy required for Growth

• AFRC (1993) predicts that for cattle the energy content of the gain made by

castrate males of a medium-sized breed can be predicted as follows:

= (4.1 + 0.0332W - 0.000009)(1 - 0.1475 LWG)

• where = energy value of liveweight gain (MJ/kg),W = liveweight (kg) and LWG =

liveweight gain (kg/day).

• The first bracketed term in the equation describes the increasing energy content

of gain as cattle increase in size, and the second term describes the correction for

the increasing energy content of gain associated with higher liveweight gains.

• To account for the effects of breed and sex on , a simple 15 per cent

correction factor has been adopted.

• Thus, for small breeds (early-maturing) and females the value

predicted is increased by 15 per cent, and for large breeds (late-

maturing) and males (bulls) the value is reduced by 15 per cent.

Energy requirements of working cattle/buffalo (light work 4 hrs)

BW (kg) DM (kg) TDN (kg) ME (Mcal)

300 6.5 3.70 13.3

350 7.6 4.15 15.0

400 8.6 4.59 16.6

450 9.7 5.01 18.1

500 10.8 5.42 19.6

550 11.9 5.83 221.0

600 13.0 6.22 22.5

650 14.0 6.60 23.8

700 15.1 6.98 25.2

Energy requirements of working cattle/buffalo (heavy work 8 hrs)

BW (kg) DM (kg) TDN (kg) ME (Mcal)

300 6.5 4.93 17.8

350 7.6 5.53 20.0

400 8.6 6.12 22.1

450 9.7 6.68 24.1

500 10.8 7.23 26.1

550 11.9 7.77 28.0

600 13.0 8.29 29.9

650 14.0 8.81 31.8

700 15.1 9.31 33.6

For Sheep

Maintenance• New born lambs (1 – 3 days old) require 117 kcal ME/.

• The maintenance requirement for growing sheep is 37.0g/ TDN.

• Kearl (1982) suggested = 92 kcal/

• requirements for grazing animal is higher than restricted animal.

• Estimates of the energy cost of walking 3.35 J (0.8 cal), 31.7 J (7.58

cal), 13.2 J (3.15 cal) / kg BW / m for horizontal, ascending and

descending movement respectively.

Energy requirement in sheep for maintenanceBody weight TDN (g) ME (M cal)

10 0.20 0.7015 0.27 0.9520 0.33 1.1825 0.39 1.3930 0.45 1.5935 0.50 1.7940 0.56 1.9845 0.61 2.1650 0.66 2.3455 0.71 2.5160 0.75 2.6865 0.80 2.8570 0.85 3.01

• As with cattle, the maintenance requirements of sheep published by

AFRC (1993) are based on fasting metabolism and an activity

allowance that varies between 0.0067 W for housed fattening lambs

and 0.024 W for ewes on hill grazing.

= 0.23 + 0.024 W

• The requirement of a 50 kg hill ewe can be predicted as follows:

= 0.23 + 0.024 W

= 5.3 MJ/day

Growth

• New born lambs (1 – 3 days old) require 0.41 kcal ME/g gain in weight.

• The growth requirement for growing sheep between 7 – 15 kg is 0.91g

of TDN/g BW gain.

• The growth requirement for growing sheep between 15 – 30 kg is 1.21g

of TDN/g BW gain.

• An average daily gain 150g was achieved in pre-weaning lambs when

feed diet containing 8.22 MJ (1.96 Mcal)/ kg of feed.

• Crossbred lambs during post-weaning phase required dietary ME 10.4

MJ (2.49)/kg feed to have ADG 112 g.

• AFRC (1993) predicts that for sheep can be predicted as follows:

Males: = 2.5 + 0.35W

Castrates: = 4.4 + 0.32W

Females: = 2.1 + 0.45W

Pregnancy and lactation

• During last trimester of pregnancy most of the energy is used by the

foetus.

• ICAR (1998) proposed ME requirements for pregnant sheep as 71 – 80

kcal ME/kg BW.

• The energy required for lactation depends on the amount and

composition of milk.

Energy pregnancy in sheep for maintenance

Body weight TDN (g) ME (M cal)15 0.40 1.4420 0.50 1.7925 0.59 2.1230 0.67 2.4335 0.75 2.7240 0.83 3.0145 0.91 3.2950 0.99 3.5655 1.06 3.8260 1.13 4.0865 1.20 4.3370 1.27 4.58

Energy lactation in sheep for maintenance

Body weight TDN (g) ME (M cal)

15 0.48 1.7320 0.60 2.1525 0.70 2.5430 0.81 2.9135 0.91 3.2740 1.00 3.6145 1.09 3.9550 1.18 4.2755 1.27 4.5960 1.36 4.9065 1.44 5.2070 1.52 5.50

For Goats

Maintenance• Mandal et al. (2005) reported maintenance requirements of TDN to be 30.1g/

• The maintenance requirements of energy is 125 kcal DE.

• The requirement for growth is 7.55 kcal/g gain.

• Mandal et al. reported that the TDN requirement for live weight gain was 1.61g/g gain.

• Rajpoot (1978) reported that energy values in terms of digestible, metabolisable, and

net energy values for growth 8.22, 6.71, and 3.78 kcal/g respectively.

Growth

Lactation

• Rajpoot (1978) reported that energy values in terms of digestible,

metabolisable, and net energy values for lactation and maintenance/

as 191, 156, and 88 kcal, respectively.

Energy requirements (per )

ParameterRequirement ( k cal )

DE ME NE

Maintenance (adult non-producing) 125 102 58

Maintenance plus gain 234 191 108

Per g gain 8 7 4

Pregnancy 227 185 104

Maintenance 191 156 88

Maintenance plus lactation 313 256 144

Per kg of 4% FCM 1520 1240 700

THANK YOU

Vishnu Vardhan Reddy.PTVM/2015-029