Merck Manual

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Nutrient Requirements of Beef Cows a

Nutrient Requirements of Beef Cows a

Months Since Calving:

1

2

3

4

5

6

7

8

9

10

11

12

NEmrequired (Mcal/day)

Maintenance

10.25

10.25

10.25

10.25

10.25

10.25

8.54

8.54

8.54

8.54

8.54

8.54

Lactation

4.78

5.74

5.17

4.13

3.10

2.23

0

0

0

0

0

0

Pregnancy

0

0

0.01

0.03

0.07

0.16

0.32

0.64

1.18

2.08

3.44

5.37

Total

15.03

15.99

15.43

14.41

13.42

12.64

8.87

9.18

9.72

10.62

11.98

13.91

MP required (g/day)b

Maintenance

422

422

422

422

422

422

422

422

422

422

422

422

Lactation

349

418

376

301

226

163

0

0

0

0

0

0

Pregnancy

0

0

1

2

4

7

14

27

50

88

151

251

Total (g)

771

840

799

725

652

592

436

449

472

510

573

673

Total (lb)

1.7

1.9

1.8

1.6

1.4

1.3

1.0

1.0

1.0

1.1

1.3

1.5

Calcium required (g/day)b

Maintenance

16

16

16

16

16

16

16

16

16

16

16

16

Lactation

16

20

18

14

11

8

0

0

0

0

0

0

Pregnancy

0

0

0

0

0

0

0

0

0

12

12

12

Total

32

36

34

30

27

24

16

16

16

28

28

28

Phosphorus required (g/day)b

Maintenance

13

13

13

13

13

13

13

13

13

13

13

13

Lactation

9

11

10

8

6

4

0

0

0

0

0

0

Pregnancy

0

0

0

0

0

0

0

0

0

5

5

5

Total

22

24

23

21

19

17

13

13

13

18

18

18

Gain in weight from pregnancy/dayb

Grams

0

0

20

30

50

80

120

190

280

400

570

770

Pounds

0

0

0.04

0.07

0.11

0.18

0.26

0.42

0.62

0.88

1.25

1.70

Milk production/day

Kilograms

6.7

8.0

7.2

5.8

4.3

3.1

0

0

0

0

0

0

Pounds

14.7

17.6

15.8

12.8

9.5

6.8

0

0

0

0

0

0

Weight of conceptus

Kilograms

0

0

1

1

3

4

7

12

19

29

44

64

Pounds

0

0

2

2

7

9

15

26

42

64

97

141

a Mature weight, 533 kg (1,172 lb); calf birth weight, 40 kg (88 lb); age at calving, 60 mo; peak milk, 8 kg (17.6 lb); age of calf at weaning, 30 wk; breed code Angus; milk protein, 3.4%; calving interval, 12 mo; see Table: Mean Nutrient Content of Feeds Commonly Used in Beef Cattle Diets a for abbreviations. Crystalline vitamin A should be added at a level of 2,200 IU/kg (1,000 IU/lb) dry matter feed.

b No allowance made for gain because these are mature cows.

Adapted, with permission, from Nutrient Requirements of Beef Cattle, 2000, National Academy of Sciences, National Academy Press, Washington, DC.