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OCR for page 102
Nutrient Requirements of Beef Cattle: Seventh Revised Edition, 1996
9
Tables of Nutrient Requirements
This seventh revised edition of Nutrient Requirements of Beef Cattle attempts to predict beef cattle requirements and performance under specific animal, environmental, and dietary conditions. Many variables (e.g., maintenance, growth, milk, microbial growth) are continuous and interact with the effects of feed composition. With this edition, the computer model described in Chapter 10 is provided on disk to calculate the effects of these variables. Because of all of the complex interactions accounted for in these models, the model tables differ from the tables of nutrient requirements in previous National Research Council (NRC) publications. Tables of nutrient requirements are, nevertheless, useful and instructive for some applications, so a computer program has been developed that uses model level 1 to compute and print nutrient requirement tables. This program allows determination of requirements for any body size and level of production of growing and finishing cattle, breeding bulls, bred heifers, and beef cows. No environmental stress is assumed. This chapter includes an example of each type of table for each of these classes of cattle, using the estimated U.S. average body size of finished steer and mature cow (533 kg). Simplified versions of these tables are provided at the end of the User’s Guide to be used as guidelines.
Two types of tables can be computed and printed. The first type, daily nutrient requirements, computes a table of daily nutrient requirements for the body size and production level specified. The second type, diet evaluator, allows the user to determine the concentration of protein, calcium (Ca), and phosphorus (P) required in a diet under specific conditions. The diet evaluator computes energy allowable production for specified diets, balances for DIP, UIP, and MP, and Ca and P needed in the diet to support the diet energy allowable production. The CP requirement is determined by adjusting diet CP and DIP until DIP and UIP requirements are met.
In addition to determining nutrient density requirements, the diet evaluator allows the user to see how well a particular diet meets requirements of cattle in a feeding group with the range of weights specified for growing cattle or at each of the 12 months of the reproductive cycle for beef cows. In most beef production situations, cattle are fed in groups that vary in stage of growth or reproduction. Each group is usually fed to appetite either available forage (stocker, backgrounding, cow-calf) or high-energy based diets (growing and finishing cattle) and are provided supplements as needed to support the energy allowable production. The objective in diet formulation for high-forage diets is to determine supplemental energy, protein, and minerals needed to meet target levels of production. The objective in high-energy diets is typically to determine the protein and minerals needed to support the energy allowable ADG. In all situations, the user attempts to develop a “best fit” diet, considering the variation of animals in a feeding group.
To use the diet evaluator, the user enters the diet TDN, CP, and percent of CP that is DIP. Diet CP and CP degradability must be entered because the relationships between CP, DIP, and UIP vary, depending on diet and animal interactions. Diet NEm, NEg, DMI, ADG, or energy balance, DIP, UIP, and MP balances (g/day) are predicted for each of the diets over a range of body weights for the body size specified for growing cattle or for each month of the reproductive cycle for breeding cattle. Next, the predicted DMI and diet NE values can be modified with adjusters until DMI and animal production level agree with observed values. Diet concentration of CP and DIP can then be altered until the requirement for the observed energy allowable production is met. The DIP balance can be increased by increasing diet CP percentage and/or increasing DIP as a percentage of CP. The UIP balance can be improved by increasing percent of CP and/or reducing DIP as a percentage of the CP.
Diet TDN is used to predict diet NEm and NEg. Diet
OCR for page 103
Nutrient Requirements of Beef Cattle: Seventh Revised Edition, 1996
NEm and NEg can only be changed by adjusting diet TDN because the relationship between these energy values must be kept consistent. Diet TDN is used to predict microbial growth, which must be consistent with the energy value used to predict NEm available to meet maintenance, pregnancy, and lactation requirements and the energy value used to predict NEg allowable ADG. To get the diet NE value desired, the user adjusts TDN until the desired NE value is predicted. The subcommittee recognizes that the relationship between TDN, ME, NEm, and NEg may vary because of differences in amount of intake, rates of digestion and passage, and end products of digestion in the ME and their metabolizability. However, the relationships between them, as described in the preceding edition of this volume published in 1984, have also been used here for the reasons discussed in Chapters 1 and 10.
The concentration of nutrients needed for a given level of production depends on the actual DMI of the diet being fed to support the observed level of performance in a particular production setting. The DMI predictions are from equations developed from experimental feeding period averages as reported in published feeding trials involving wide variations in cattle type and stage of growth, as discussed in Chapter 7. Thus, predicted and observed values often differ in a specific production setting. Cattle fed feedlot finishing rations will typically consume 0 to 25 percent more early in the feeding period than predicted by these equations, which is compensated for by DMI of 0 to 25 percent less late in the feeding period. Further, as discussed in Chapter 7, concerning feed intake, most DMI prediction equations account for only 50 to 60 percent of the variation, leaving 40 to 50 percent to be accounted for by variations in local conditions such as feeding management, cattle type, and environment. The DMI adjusters allow the user to change the predicted DMI until it agrees with observed DMI; then the NE adjuster can be changed until predicted and observed performance agree.
Many factors can influence the NE derived from a diet for production, including variation in maintenance requirements, rates of digestion and passage, and metabolizability. If only DMI is adjusted, predicted and observed performance may not agree. For example, unrealistically high rates and efficiencies of gain may be predicted for calves consuming high-energy rations. Conversely, when these animals approach choice grade at the end of the finishing period, unrealistically low ADG may be predicted if only DMI is adjusted. Given these problems of prediction early and late in growth, limits were set on the weight ranges in the diet density tables at 55 percent of finished weight for the lightest weight and 80 percent of finished weight for the heaviest weight.
The primary use of these tables is intended to be for teaching the interactions of body size, stage of growth, diet energy density, and energy and protein requirements. The diet densities for CP and DIP may not be practical because the CP may have to be overfed to meet both DIP and UIP requirements. The user is encouraged to use the model with actual feed ingredients available for computing requirements for specific conditions. Despite their limitations as discussed in this section, simple guideline tables with diet nutrient concentration requirements for different classes of cattle are all that are needed in many situations and are provided at the end of the User’s Guide.
EXAMPLE TABLES FOR GROWING AND FINISHING CATTLE
Tables 9–1 and 9–2 show daily requirements (Table 9–1) and diet evaluations (Table 9–2) for growing and finishing cattle. Inputs for Table 9–1 are for a 533-kg finished weight at 28 percent fat, a weight range of 200 to 450 kg, an ADG range of 0.50 to 2.50 kg, and breed code 1. Table 9–1 shows NEm, NEg, MP, Ca, and P required daily for maintenance and gain at six shrunk body weights, which represent six different stages of growth. All these requirements can be used directly to formulate dietary requirements for the specified level of performance, except the diet CP, DIP, and UIP required to meet the MP requirement. The CP intake needed can be estimated by dividing the total MP requirement in this table by 0.67, which is based on 80 percent of the MP from MCP and 20 percent from UIP. This approach was used in developing the guideline tables at the end of the User’s Guide. However, this assumes that the nitrogen difference between the diet CP and MP requirement will meet microbial requirements for DIP and tissue requirements for UIP. This approach, which was used in the preceding edition of this volume to compute CP requirements, has major limitations. For this edition, the dietary CP intake needed is computed in the model level 1 as a sum of the DIP needed for microbial growth plus the UIP needed above the MP required for maintenance plus gain not met by microbial protein. These variables are not directly accounted for when the CP required is determined as MP/0.67.
Table 9–2 shows the evaluation of five diets (rations A through E) with the diet evaluator for the same animal used in Table 9–1 between 55 and 80 percent of final weight. The diet concentration of eNDF, TDN, and CP and DIP as a percentage of CP were entered for each of the five diets, and all DMI and NE adjusters were set at 100 percent. The eNDF values are used to adjust microbial protein yield and are affected only when diet eNDF drops below 20 percent of diet DM. The feed eNDF values in Appendix Table 1 (the feed library) can be used to determine eNDF in the diet. The program first computed diet NEm and NEg values, DMI, energy allowable ADG, MP, Ca, and P required for that ADG, MCP from the TDN
OCR for page 104
Nutrient Requirements of Beef Cattle: Seventh Revised Edition, 1996
TABLE 9–1 Nutrient Requirements for Growing and Finishing Cattle
Wt @ Small marbling
533 kg
Weight range
200–450 kg
ADG range
0.50–2.50 kg
Breed Code
1 Angus
Body Weight, kg
200
250
300
350
400
450
Maintenance Requirements
NEm
Mcal/d
4.1
4.84
5.55
6.23
6.89
7.52
MP
g/d
202
239
274
307
340
371
Ca
g/d
6
8
9
11
12
14
P
g/d
5
6
7
8
10
11
Growth Requirements
(ADG)
NEg required for gain, Mcal/d
0.5
kg/d
1.27
1.50
1.72
1.93
2.14
2.33
1.0
kg/d
2.72
3.21
3.68
4.13
4.57
4.99
1.5
kg/d
4.24
5.01
5.74
6.45
7.13
7.79
2.0
kg/d
5.81
6.87
7.88
8.84
9.77
10.68
2.5
kg/d
7.42
8.78
10.06
11.29
12.48
13.64
MP required for gain, g/d
0.5
kg/d
154
155
158
157
145
133
1.0
kg/d
299
300
303
298
272
246
1.5
kg/d
441
440
442
432
391
352
2.0
kg/d
580
577
577
561
505
451
2.5
kg/d
718
712
710
687
616
547
Calcium required for gain, g/d
0.5
kg/d
14
13
12
11
10
9
1.0
kg/d
27
25
23
21
19
17
1.5
kg/d
39
36
33
30
27
25
2.0
kg/d
52
47
43
39
35
32
2.5
kg/d
64
59
53
48
43
38
Phosphorus required for gain, g/d
0.5
kg/d
6
5
5
4
4
4
1.0
kg/d
11
10
9
8
8
7
1.5
kg/d
16
15
13
12
11
10
2.0
kg/d
21
19
18
16
14
13
2.5
kg/d
26
24
22
19
17
15
intake, and DIP required for the MCP produced and UIP required with the equations presented in Chapter 10 for level 1.
All five diets were then balanced for UIP and DIP for the 300-kg body weight category by changing both CP and DIP until both UIP and DIP were balanced. The DIP is balanced for all other weights for each diet because MCP yield stays constant at 13 percent of TDN. The UIP would be deficient at lighter weights because the animal tissue requirement for protein at the energy allowable ADG exceeds the MCP and UIP provided by the diet. At weights less than 300 kg, the UIP deficiency would increase with the high-energy diets compared to low-energy diets because their lower eNDF results in a lower rumen pH, which reduces microbial growth as described in Chapter 2. This deficiency can be overcome by increasing the CP and lowering the DIP, but not to exceed that needed to balance DIP, until the UIP requirement is met. In practical diets, this means substituting sources of DIP in the supplement with sources of UIP. At weights more than 300 kg, the diet UIP provided exceeds the MP required because of less protein in the ADG as the cattle increase in weight. The UIP excess can be decreased by lowering the CP while increasing the DIP as needed to keep the DIP balanced. The only practical way to accomplish this in the diet formula is to replace sources of UIP with sources of DIP until the CP and DIP reach a level provided by the grain and forage plus urea.
If actual data were available, predicted DMI would have been adjusted until it agreed with observed DMI, then the NE adjusters would have been used to adjust feed NE values until predicted and observed performance agree.
OCR for page 105
Nutrient Requirements of Beef Cattle: Seventh Revised Edition, 1996
TABLE 9–2 Diet Evaluation for Growing and Finishing Cattle
Wt @ Small Marbling
533 kg
Breed Code
1 Angus
Ration
eNDF % DM
TDN % DM
NEm Mcal/kg
NEg Mcal/kg
CP % DM
DIP % CP
Weight Class
NE Adjuster
A
57
50
1.00
0.45
7.4
88
325
100%
B
43
60
1.35
0.77
10.0
78
350
100%
C
30
70
1.67
1.06
12.6
72.4
375
100%
D
5
80
1.99
1.33
14.4
48.5
400
100%
E
3
90
2.29
1.59
16.6
44.2
425
100%
Body Weight, kg
DMI Adjuster
DMI kg/d
ADG kg/d
DIP
UIP
MP
Ca
P
balances, g/d
requirements, % of DM
300—A
100%
7.9
0.32
1
0
0
0.22%
0.13%
—B
100%
8.4
0.89
0
0
0
0.35%
0.18%
—C
100%
8.2
1.36
2
0
0
0.48%
0.24%
—D
100%
7.7
1.69
1
2
1
0.60%
0.29%
—E
100%
7.1
1.90
1
2
1
0.71%
0.34%
325—A
100%
8.4
0.32
1
14
11
0.21%
0.13%
—B
100%
8.9
0.89
0
38
30
0.33%
0.18%
—C
100%
8.7
1.36
2
57
46
0.45%
0.22%
—D
100%
8.2
1.69
1
73
58
0.55%
0.27%
—E
100%
7.6
1.90
1
82
66
0.65%
0.31%
350—A
100%
8.9
0.32
1
27
22
0.20%
0.13%
—B
100%
9.4
0.89
0
75
60
0.31%
0.17%
—C
100%
9.2
1.36
2
114
91
0.42%
0.21%
—D
100%
8.7
1.69
1
143
114
0.51%
0.25%
—E
100%
8.0
1.90
1
160
128
0.60%
0.29%
375—A
100%
9.4
0.32
1
40
32
0.20%
0.13%
—B
100%
9.9
0.89
0
111
89
0.30%
0.16%
—C
100%
9.7
1.36
2
169
135
0.39%
0.20%
—D
100%
9.1
1.69
1
212
169
0.48%
0.24%
—E
100%
8.4
1.90
1
238
190
0.56%
0.28%
400—A
100%
9.8
0.32
1
53
43
0.19%
0.12%
—B
100%
10.4
0.89
0
147
118
0.28%
0.16%
—C
100%
10.2
1.36
2
223
178
0.37%
0.19%
—D
100%
9.6
1.69
2
279
223
0.44%
0.23%
—E
100%
8.8
1.90
1
314
251
0.52%
0.26%
425—A
100%
10.3
0.32
1
66
53
0.19%
0.12%
—B
100%
10.9
0.89
0
182
146
0.27%
0.15%
—C
100%
10.6
1.36
2
276
221
0.35%
0.19%
—D
100%
10.0
1.69
2
346
277
0.42%
0.22%
—E
100%
9.3
1.90
1
388
311
0.48%
0.25%
OCR for page 106
Nutrient Requirements of Beef Cattle: Seventh Revised Edition, 1996
TABLE 9–3 Nutrient Requirements for Growing Bulls
Wt @ Maturity
890 kg
Weight Range
300–800 kg
ADG Range
0.50–2.50 kg
Breed Code
1 Angus
Body Weight, kg
300
400
500
600
700
800
Maintenance Requirements
NEm
Mcal/day
6.38
7.92
9.36
10.73
12.05
13.32
MP
g/d
274
340
402
461
517
572
Ca
g/d
9
12
15
19
22
25
P
g/d
7
10
12
14
17
19
Growth Requirements
ADG
NEg Required for Gain, Mcal/d
0.5
kg/d
1.72
2.13
2.52
2.89
3.25
3.59
1.0
kg/d
3.68
4.56
5.39
6.18
6.94
7.67
1.5
kg/d
5.74
7.12
8.42
9.65
10.83
11.97
2.0
kg/d
7.87
9.76
11.54
13.23
14.85
16.41
2.5
kg/d
10.05
12.47
14.74
16.90
18.97
20.97
MP Required for Gain g/d
0.5
kg/d
158
145
122
100
78
58
1.0
kg/d
303
272
222
175
130
86
1.5
kg/d
442
392
314
241
170
102
2.0
kg/d
577
506
400
299
202
109
2.5
kg/d
710
617
481
352
228
109
Calcium Required for Gain, g/d
0.5
kg/d
12
10
9
7
6
4
1.0
kg/d
23
19
16
12
9
6
1.5
kg/d
33
27
22
17
12
7
2.0
kg/d
43
35
28
21
14
8
2.5
kg/d
53
43
34
25
16
8
Phosphorus Required for Gain, g/d
0.5
kg/d
5
4
3
3
2
2
1.0
kg/d
9
8
6
5
4
2
1.5
kg/d
13
11
9
7
5
3
2.0
kg/d
18
14
11
8
6
3
2.5
kg/d
22
17
14
10
6
3
EXAMPLE TABLES FOR BREEDING BULLS
Tables 9–3 and 9–4 are example nutrient requirement (Table 9–3) and diet evaluation (Table 9–4) tables for growing bulls, using an 890-kg mature weight. Diet inputs for Table 9–4 were made as described for Table 9–2, with different diet TDN values. Weight ranges were set as 55 to 80 percent of the 28 percent fat weight of a steer of the same genotype (bull mature SBW * 0.6). (See Chapter 3 for the biological basis for computing bull requirements.) Diet CP, DIP, and UIP were balanced as described for Table 9–2 for 300 kg, except for diet A, for which upper bound of 80 percent DIP was used. The interpretations and applications are as described for Table 9–2.
OCR for page 107
Nutrient Requirements of Beef Cattle: Seventh Revised Edition, 1996
TABLE 9–4 Diet Evaluation for Growing Bulls
Wt @ Maturity
890 kg
Breed Code
1 Angus
Ration
eNDF % DM
TDN % DM
NEm Mcal/kg
NEg Mcal/kg
CP % DM
DIP % CP
Weight Class
NE Adjuster
A
43
50
1.00
0.45
8.2
80
325
100%
B
37
65
1.51
0.92
10.9
78
350
100%
C
30
70
1.67
1.06
12.0
76
375
100%
D
20
75
1.83
1.20
13.4
73
400
100%
E
5
80
1.99
1.33
13.8
51
425
100%
Body Weight, kg
DMI Adjuster
DMI kg/d
ADG kg/d
DIP
UIP
MP
Ca
P
balances, g/d
requirements, % of DM
300—A
100%
7.9
0.22
5
103
83
0.18%
0.12%
—B
100%
8.3
1.02
4
8
6
0.39%
0.20%
—C
100%
8.2
1.23
2
-3
-2
0.45%
0.23%
—D
100%
8.0
1.41
3
10
8
0.51%
0.25%
—E
100%
7.7
1.56
5
-2
-2
0.56%
0.27%
325—A
100%
8.4
0.22
5
119
95
0.18%
0.12%
—B
100%
8.8
1.02
5
51
41
0.36%
0.19%
—C
100%
8.7
1.23
2
49
39
0.42%
0.21%
—D
100%
8.5
1.41
3
70
56
0.47%
0.24%
—E
100%
8.2
1.56
6
63
51
0.52%
0.26%
350—A
100%
8.9
0.22
5
134
107
0.18%
0.12%
—B
100%
9.4
1.02
5
94
75
0.34%
0.18%
—C
100%
9.2
1.23
2
100
80
0.39%
0.20%
—D
100%
9.0
1.41
3
129
103
0.44%
0.22%
—E
100%
8.7
1.56
6
128
102
0.48%
0.24%
375—A
100%
9.4
0.22
6
149
119
0.18%
0.12%
—B
100%
9.8
1.02
5
136
109
0.32%
0.17%
—C
100%
9.7
1.23
2
150
125
0.37%
0.19%
—D
100%
9.4
1.41
3
187
149
0.41%
0.21%
—E
100%
9.1
1.56
6
191
153
0.45%
0.23%
400—A
100%
9.8
0.22
6
161
131
0.17%
0.12%
—B
100%
10.3
1.02
5
177
142
0.31%
0.17%
—C
100%
10.2
1.23
2
199
159
0.35%
0.19%
—D
100%
9.9
1.41
3
244
195
0.39%
0.20%
—E
100%
9.6
1.56
7
253
202
0.42%
0.22%
425—A
100%
10.3
0.22
6
169
143
0.17%
0.12%
—B
100%
10.8
1.02
6
218
174
0.29%
0.16%
—C
100%
10.6
1.23
2
247
198
0.33%
0.18%
—D
100%
10.4
1.41
3
300
240
0.36%
0.19%
—E
100%
10.0
1.56
7
314
251
0.40%
0.21%
OCR for page 108
Nutrient Requirements of Beef Cattle: Seventh Revised Edition, 1996
TABLE 9–5 Nutrient Requirements of Pregnant Replacement Heifers
Mature Weight
533 kg
Calf Birth Weight
40 kg
Age @ Breeding
15 months
Breed Code
1 Angus
Months since conception
1
2
3
4
5
6
7
8
9
NEm required, Mcal/d
Maintenance
5.98
6.14
6.30
6.46
6.61
6.77
6.92
7.07
7.23
Growth
2.29
2.36
2.42
2.48
2.54
2.59
2.65
2.71
2.77
Pregnancy
0.03
0.07
0.16
0.32
0.64
1.18
2.08
3.44
5.37
Total
8.31
8.57
8.87
9.26
9.79
10.55
11.65
13.23
15.37
MP required, g/d
Maintenance
295
303
311
319
326
334
342
349
357
Growth
118
119
119
119
119
117
115
113
110
Pregnancy
2
4
7
18
27
50
88
151
251
Total
415
425
437
457
472
501
545
613
718
Minerals
Calcium required, g/d
Maintenance
10
11
11
11
12
12
12
13
13
Growth
9
9
9
8
8
8
8
8
8
Pregnancy
0
0
0
0
0
0
12
12
12
Total
19
19
20
20
20
20
33
33
33
Phosphorus required, g/d
Maintenance
8
8
8
9
9
9
10
10
10
Growth
4
4
3
3
3
3
3
3
3
Pregnancy
0
0
0
0
0
0
7
7
7
Total
12
12
12
12
12
13
20
20
20
ADG, kg/d
Growth
0.39
0.39
0.39
0.39
0.39
0.39
0.39
0.39
0.39
Pregnancy
0.03
0.05
0.08
0.12
0.19
0.28
0.40
0.57
0.77
Total
0.42
0.44
0.47
0.51
0.58
0.67
0.79
0.96
1.16
Body weight, kg
Shrunk body
332
343
355
367
379
391
403
415
426
Gravid uterus mass
1
3
4
7
12
19
29
44
64
Total
333
346
360
375
391
410
432
459
491
EXAMPLE TABLES FOR PREGNANT REPLACEMENT HEIFERS
Tables 9–5 and 9–6 contain requirements (Table 9–5) and diet evaluations (Table 9–6) for pregnant heifers. As with the preceding table sets, these two tables are related in that the animal described in the requirements table is then used in the diet evaluator. The program computes energy and protein balances expected for each of the three diets (rations A through C) entered as well as percent Ca and P needed in the diet DM to meet requirements. Animal descriptions entered were 533 kg mature weight, 40 kg expected birth weight, 15 month age at breeding, and breed code 1. Table 9–5 shows predicted NEm, MP, Ca, and P required daily for maintenance, growth, and pregnancy and target ADG, SBW, and expected gravid uterus weight used to compute requirements for each of 9 months of gestation, 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 the MP requirement, which can be computed as described for Table 9–2.
Table 9–6 shows diet evaluations for this same heifer. The diet concentration of TDN and CP and DIP as a percentage of CP were entered for each of the three diets and the intake multiplier was set at 100 percent. All DIP values were then set at 80 percent, and diet CP was adjusted until DIP requirement was approximately met. Predicted DMI increased as pregnancy progressed because of increasing predicted SBW (shown in Table 9–5). As with the growing and finishing cattle, the DIP balance was constant over gestation for a given diet because microbial requirement is a constant proportion of TDN. However, the UIP balance changes with composition of the ADG (reduced protein content of ADG with increasing weight) and conceptus requirements. The CP, DIP, and UIP requirements are determined as described for growing and finishing cattle. Diet A (50 percent TDN) does not supply enough energy to support target heifer growth during any month. Diet B (60 percent TDN) exceeds target energy allowable ADG in all but the last month of pregnancy and exceeded UIP requirements for the energy allowable ADG in all but the first month. Diet C (70 percent TDN) exceeded target ADG in all months, but UIP was deficient for the energy allowable ADG in all but months 7 and 8.
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Nutrient Requirements of Beef Cattle: Seventh Revised Edition, 1996
TABLE 9–6 Diet Evaluation for Pregnant Replacement Heifers
Mature Weight
533 kg
Calf Birth Weight
40 kg
Age @ Breeding
15 months
Breed Code
1 Angus
Ration
TDN % DM
NEm Mcal/kg
NEg Mcal/kg
CP % DM
DIP % DM
DMI Factor
A
50
1.00
0.45
8.2
80
100%
B
60
1.35
0.77
9.8
80
100%
C
70
1.67
1.06
11.4
80
100%
Months Since Conception
1
2
3
4
5
6
7
8
9
NEm Req. Factor
100%
100%
100%
100%
100%
100%
100%
100%
100%
A
DM, kg
8.5
8.8
9.0
9.2
9.4
9.7
9.9
10.1
10.3
NE allowed ADG
0.35
0.34
0.33
0.31
0.28
0.22
0.12
0.00
0.00
DIP Balance, g/d
5
5
5
6
6
6
6
6
6
UIP Balance, g/d
75
79
83
87
90
92
90
66
-53
MP Balance, g/d
60
63
67
69
72
74
72
52
-42
Ca % DM
0.22%
0.21%
0.21%
0.20%
0.19%
0.18%
0.28%
0.25%
0.25%
P % DM
0.17%
0.17%
0.16%
0.16%
0.15%
0.14%
0.19%
0.16%
0.16%
B
DM, kg
9.0
9.3
9.5
9.7
10.0
10.2
10.4
10.7
10.9
NE allowed ADG
0.96
0.96
0.95
0.92
0.88
0.82
0.71
0.54
0.30
DIP Balance, g/d
4
4
4
4
4
4
4
4
4
UIP Balance, g/d
5
14
22
30
38
49
54
46
18
MP Balance, g/d
4
11
18
24
31
40
43
37
14
Ca % DM
0.36%
0.35%
0.33%
0.32%
0.31%
0.29%
0.38%
0.34%
0.29%
P % DM
0.27%
0.27%
0.26%
0.26%
0.25%
0.23%
0.27%
0.24%
0.20%
C
DM, kg
8.8
9.1
9.3
9.5
9.8
10.0
10.2
10.4
10.7
NE allowed ADG
1.47
1.46
1.45
1.42
1.38
1.31
1.19
1.02
0.77
DIP Balance, g/d
2
2
2
2
2
2
2
2
2
UIP Balance, g/d
-66
-54
-43
-32
-19
-1
10
8
-18
MP Balance, g/d
-53
-43
-34
-26
-15
-1
8
6
-14
Ca % DM
0.48%
0.47%
0.45%
0.43%
0.41%
0.39%
0.48%
0.43%
0.38%
P % DM
0.37%
0.36%
0.35%
0.35%
0.33%
0.31%
0.35%
0.32%
0.28%
NOTE: Requirements are for NE allowed ADG and target weight. NE allowed ADG is ADG independent of conceptus gain.
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Nutrient Requirements of Beef Cattle: Seventh Revised Edition, 1996
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
OCR for page 111
Nutrient Requirements of Beef Cattle: Seventh Revised Edition, 1996
TABLE 9–8 Diet Evaluation for 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
Ration
TDN % DM
ME Mcal/kg
NEm Mcal/kg
CP % DM
DIP % CP
DMI Factor
A
50
1.84
1.00
7.9
82.5
100%
B
60
2.21
1.35
7.8
100.0
100%
C
70
2.58
1.67
9.1
100.0
100%
Months 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%
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
A
DM, kg
11.14
11.40
12.12
11.83
11.54
11.30
10.68
10.68
10.68
10.68
10.68
10.68
Energy Balance, Mcal/d
-3.90
-4.59
-3.31
-2.58
-1.88
-1.34
1.81
1.50
0.95
0.06
-1.30
-3.24
DIP Balance, g/d
7
7
7
7
7
7
6
6
6
6
6
6
UIP Balance, g/d
-201
-270
-169
-96
-24
34
175
170
142
93
14
-110
MP Balance, g/d
-161
-216
-136
-77
-19
27
149
136
113
75
11
-88
Ca % DM
0.65%
0.70%
0.62%
0.57%
0.52%
0.47%
0.34%
0.34%
0.34%
0.59%
0.59%
0.59%
P % DM
0.20%
0.21%
0.19%
0.18%
0.16%
0.15%
0.12%
0.12%
0.12%
0.17%
0.17%
0.17%
Reserves Flux/mo, Mcal
-148
-174
-126
-98
-71
-51
55
46
29
2
-50
-123
B
DM, kg
11.96
12.23
12.72
12.43
12.14
11.90
11.28
11.28
11.28
11.28
11.28
11.28
Energy Balance, Mcal
1.07
0.47
1.69
2.32
2.92
3.38
6.32
6.00
5.46
4.56
3.20
1.27
DIP Balance, g/d
5
5
5
5
5
5
5
5
5
5
5
5
UIP Balance, g/d
18
-47
44
114
182
233
221
221
221
221
209
85
MP Balance, g/d
14
-38
35
91
146
189
304
291
269
230
167
68
Ca % DM
0.27%
0.30%
0.27%
0.25%
0.22%
0.20%
0.15%
0.15%
0.15%
0.25%
0.25%
0.25%
P % DM
0.19%
0.20%
0.18%
0.17%
0.16%
0.14%
0.11%
0.11%
0.11%
0.16%
0.16%
0.16%
Reserves Flux/mo, Mcal
32
14
51
71
89
103
192
183
166
139
97
39
C
DM, kg
13.16
13.42
13.79
13.50
13.21
12.97
12.35
12.35
12.35
12.35
12.35
12.35
Energy Balance, Mcal/d
6.99
6.48
7.65
8.18
8.69
9.07
11.80
11.49
10.95
10.05
8.69
6.76
DIP Balance, g/d
3
3
3
3
3
3
2
2
2
2
2
2
UIP Balance, g/d
295
233
314
308
301
296
282
282
282
282
282
282
MP Balance, g/d
236
187
256
308
360
401
509
496
473
435
371
272
Ca % DM
0.25%
0.27%
0.25%
0.23%
0.20%
0.19%
0.13%
0.13%
0.13%
0.23%
0.23%
0.23%
P % DM
0.17%
0.18%
0.17%
0.15%
0.14%
0.13%
0.10%
0.10%
0.10%
0.14%
0.14%
0.14%
Reserves Flux/mo, Mcal
212
197
233
249
264
276
359
349
333
306
264
205
intake multiplier was set at 100 percent. All DIP values were then set at 80 percent, and diet CP was adjusted until DIP requirements were close to being balanced. Predicted DMI varies with daily milk production and forage quality. The CP required to meet diet DIP required for microbial growth is constant for a given diet but increased as diet TDN increased because microbial growth is a constant proportion of TDN. However, the UIP balance changes with milk and pregnancy requirements.
Diet A (50 percent TDN) met energy and UIP requirements in months 7 to 10 (cows just dry), became deficient in energy in month 11, and deficient in both energy and UIP in month 12. Diet B (60 percent TDN) is adequate in energy in all months and UIP in all but month 2 of lactation. Diet C (70 percent TDN) exceeded energy and UIP requirements in all months.
The energy reserves flux (Mcal/mo) is given for each month of the reproductive cycle for each diet evaluated. Appendix Table 13 can be used to estimate days for a CS change by dividing the Appendix Table 13 value by the predicted daily energy balance. To reduce a negative energy balance, 1 Mcal diet NEm will substitute for 1 Mcal negative energy balance. To utilize energy reserves, 1 Mcal diet NEm can be replaced by 0.8 Mcal tissue energy.
TABLE OF ENERGY RESERVES FOR BEEF COWS
Appendix Table 13 gives Mcal mobilized in moving to the next lower CS, or required to move from the next lower CS to the one being considered, for cows with different mature weights. For example, a 500-kg cow at CS 5 will mobilize 207 Mcal in declining to a CS 4. If NEm intake is deficient 3 Mcal/day, this cow will lose 1 CS in (207 * 0.8)/3=55 days. If consuming 3 Mcal NEm above
OCR for page 112
Nutrient Requirements of Beef Cattle: Seventh Revised Edition, 1996
daily requirements, this cow will move from a CS 4 to a CS 5 in 207/3=69 days. The equations developed for computation of energy reserves are discussed in Chapter 3.
TABLE OF MAINTENANCE REQUIREMENT MULTIPLIERS FOR ENVIRONMENTAL CONDITIONS
The program used to develop the tables of requirements does not adjust for environmental conditions. Appendix Table 14 gives multipliers developed from the computer model level 1 that can be used to adjust NEm requirements for environmental stress.
Representative terms from entire chapter:
energy allowable