V. Considerations when feeding for milk production

A. Feed young growing cows enough to allow for growth as well as for maintenance & milk production. It is best to group cows by production level.

B. More cows are underfed on energy than protein

C. Concentrate mix should contain:

1. Energy

2. Protein

3. .5 to 1% trace mineralized salt

4. 1 to 2% Ca-P supplement

5. No more than 6% molasses

6. No more than 1% urea

D. It is best to feed some hay with silage

E. Cow will consume 3 to 5 lb of water / lb milk

F. Consider relationships of feeds to milk flavor. (Remove from wheat pasture several hours before milking to prevent off-flavor)
G. Protein for Dairy Cows

1.      Rumen Degraded Intake Protein (DIP)

a.    Degraded by microbes in the rumen

2.  Rumen un-degraded Intake Protein (UIP)

a. By-pass, escape protein

3.  Advantage for using DIP/UIP

a.   Decrease overall crude protein in diet

b.  Resulting in reduced cost of ration

4.  Urea Fermentation Potential

a.  Evaluation of the useful urea in a ration

b.  An estimation of the g urea/kg DM that can be converted to microbial protein

c.  The value is dependant upon the energy in the diet

d.  A negative value indicates no protein would be synthesized with the energy available

H. BST for Dairy Cows

1.  Bovine Somatotropin = a Natural product produced in the pituitary (growth hormone)

2.  Subcutaneous injection every 14 days

3.  Approved (FDA) for health cows beginning 9th wk of lactation

4.  Injection results in:

a.  Immediate (2 – 3 d) increased milk production

i.  8 – 22% (5 to 15 lb milk/d
b.  Nutrients directed from body tissues to mammary gland

c.  Increased intake (nutrients) needed because of improved performance

d.  DM intake not increased (as result of BST) until 3 – 6 wk post injection (3 – 5 lb/d)

i.  Usually results in decreased body condition

5.  Effect on Reproduction:

a.  Increased days open (reduced pregnancy rate)

b.  Increased twinning

c.  Increased lameness

d.  Increased mastitis

 

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

8.92 23.61 kg 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