VI. Balancing a ration for a lactating dairy cow
Calculate a balanced Dairy Ration for an 800 kg mature dairy cow producing 32 kg of 3.5% milk daily.
TABLE 9-5
|
NEL(Mcal)
|
CP (kg)
|
Ca (kg)
|
P (kg)
|
|
| Maintenance |
12.03
|
.486
|
.032
|
.023
|
| Lactation |
22.08
|
2.688
|
.095
|
.058
|
| Total Requirement |
34.11
|
3.174
|
.127
|
.081
|
FEEDS
| FEEDSTUFF |
NEL(Mcal/kg)
|
CP (%)
|
Ca (%)
|
P (%)
|
| Corn Silage (34% DM) |
.54(1.43)
|
2.8(7.41)
|
.09(.24)
|
.07(.18)
|
| Grass Hay |
1.01
|
8.5
|
.45
|
.20
|
| Corn |
1.84
|
8.8
|
.02
|
.29
|
| Oats |
1.55
|
11.8
|
.08
|
.34
|
| SBM |
1.78
|
43.3
|
.26
|
.62
|
*() = values for sialge on a 90% DM basis
Use Table 9-7 to get DM intake, but need milk on a 4% basis:
4% FCM = (.4 X kg milk) + (15 X kg fat)
= (.4 X 32) + (15 X 1.12)
= 29.6 look up on Table 9-7 (30 kg milk produced) ==> 2.8% BW
800 X .028 = 22.4/.9 = 24.89 kg air-dry basis
X = Forage (50% hay, 50% silage)
24.89-X = Conc. (70% corn, 30% oats)
Need silage on an air-dry basis; (2.8/34 = X/90 ==> X = 7.41% CP, See figure above)
Forage: .5(1.01) + .5(1.43) = 1.22
Conc.: .7(1.84) + .3(1.55) = 1.75
1.22(X) + 1.75 (24.89 -X) = 34.11
1.22X + 43.56 - 1.75X = 34.11
-.53X = -9.45
X = 17.83
X = 17.83
24.89 - X = 6.96
|
CP
|
NEL
|
|
| 8.92 silage |
.66
|
12.76
|
| 8.92 hay |
.76
|
9.01
|
| 4.94 corn |
.43
|
9.09
|
| 2.11 oats |
.25
|
3.27
|
| TOTAL |
2.10
|
34.13
|
| REQUIRED |
3.174
|
34.11
|
| difference |
-1.074
|
OK
|
Substitute SBM for corn ==> Net .433 - .088 = .345
1.074/.345 = 3.11
FINAL DIET
| Corn silage (DO NOT forget to convert to AS-FED basis | |
| 8.92 kg | Grass hay |
| 1.83 kg | Corn |
| 2.11 kg | Oats |
| 3.11 kg | SBM |
| Calculate minerals as other diets | |
Balancing Dairy Rations
I. Establish needs - maintenance + lactation + reproduction
II. Determine available feeds and their composition
A. Forage
1. Kind (legume VS grass)
2. Quality
B. Concentrate Mix
1. Kind - determined by protein level of forage
2. Amount - determined by amount of energy needed
III. Establish feeding levels
A. Guidelines in Table 9-7
B. Determine amount of forage VS concentrate using energy
IV. Balance
A. Subtract nutrients supplied by forage from amount needed
B. Using a concentrate mix supply additional needs
C. Check