Table 9–7 Nutrient Requirements of Beef Cows

Mature Weight

533 kg

Milk Fat

4.0 %

 

Calf Birth Weight

40 kg

Milk Protein

3.4 %

Age @ Calving

60 months

Calving Interval

12 months

Age @ Weaning

30 weeks

Time Peak

8.5 weeks

Peak Milk

8 kg

Milk SNF

8.3 %

Breed Code

1 Angus

 

Month since Calving

 

1

2

3

4

5

6

7

8

9

10

11

12

NEm Req. Factor

100%

100%

100%

100%

100%

100%

100%

100%

100%

100%

100%

100%

NEm required, Mcal/d

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

Growth

0.00

0.00

0.00

0.00

0.00

0.00

0.00

0.00

0.00

0.00

0.00

0.00

Lactation

4.78

5.74

5.17

4.13

3.10

2.23

0.00

0.00

0.00

0.00

0.00

0.00

Pregnancy

0.00

0.00

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/d

Maintenance

422

422

422

422

422

422

422

422

422

422

422

422

Growth

0

0

0

0

0

0

0

0

0

0

0

0

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

770

840

799

724

651

591

436

449

471

510

573

672

Calcium required, g/d

Maintenance

16

16

16

16

16

16

16

16

16

16

16

16

Growth

0

0

0

0

0

0

0

0

0

0

0

0

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

33

36

34

31

27

24

16

16

16

29

29

29

Phosphorus required, g/d

Maintenance

13

13

13

13

13

13

13

13

13

13

13

13

Growth

0

0

0

0

0

0

0

0

0

0

0

0

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

ADG, kg/d

Growth

0.00

0.00

0.00

0.00

0.00

0.00

0.00

0.00

0.00

0.00

0.00

0.00

Pregnancy

0.00

0.00

0.02

0.03

0.05

0.08

0.12

0.19

0.28

0.40

0.57

0.77

Total

0.00

0.00

0.02

0.03

0.05

0.08

0.12

0.19

0.28

0.40

0.57

0.77

Milk kg/d

6.7

8.0

7.2

5.8

4.3

3.1

0.0

0.0

0.0

0.0

0.0

0.0

Body weight, kg

Shrunk Body

533

533

533

533

533

533

533

533

533

533

533

533

Conceptus

0

0

1

1

3

4

7

12

19

29

44

64

Total

533

533

534

534

536

537

540

545

552

562

577

597

EXAMPLE TABLES FOR BEEF COWS

Tables 9–7 and 9–8 contain requirements (Table 9–7) and diet evaluations (Table 9–8) for beef cows. As with the bred heifers, these two tables are related; the animal described in the requirements table is used in the diet evaluator. It computes energy and protein balances expected for each of the three diets (rations A through C) entered and percent Ca and P needed in the diet DM to meet requirements. Animal descriptions entered were 533 kg mature weight, breed code 1, 40 kg expected birth weight, 60 months age, the breed default peak milk (8 kg), the default values for milk composition (4 percent fat, 3.4 percent protein, 8.3 percent solids not fat), 8.5 weeks at peak milk, and 30 months duration of lactation. Table 9–7 shows predicted NEm, NEg, MP, Ca, and P required daily for maintenance, growth, lactation, and pregnancy as well as predicted target ADG, SBW, daily milk production, and expected gravid uterus weight used to compute the requirements for each of the 12 months of the reproductive cycle using the equations presented in Chapter 10. As described previously, all can be used directly to formulate dietary requirements for the specified level of performance, except diet CP intake to meet DIP and UIP requirements, which can be computed as described for Table 9–2.

Table 9–8 shows diet evaluations for this same cow. The diet concentration of TDN and CP and DIP as a percentage of CP were entered for each of the three diets and the



The National Academies | 500 Fifth St. N.W. | Washington, D.C. 20001
Copyright © National Academy of Sciences. All rights reserved.
Terms of Use and Privacy Statement