b. Milk Fever

1. Correlated with number of lactation�s

(50 X greater in cows with more than 6 compared to those in first lactation)

2. 75% of cases occur at or within 24 hour of parturition

3. Symptoms

drowsy, head turns into flank

4. Decreased blood Ca

5. Treatment

- IV Ca

- prevent with low Ca diet 2 to 3 wks before calving (difficult to find this kind of diet)

- Vit. D before calving, but toxic so must know exact calving date!!

- Decrease DCAD (ratio of cations to anions in the diet)

 

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