DAIRY RATIONS

I. General

A. Feeding, more than any other single factor, determines productivity of lactating dairy cows.

1. Feed represents ~50% of total cost

B. Nutrient requirements for lactation are often several times the maintenance requirement.

1. Remember that:

-more variation exists in protein content than energy among various forages and concentrates.

-in balancing dairy cow rations, use NE_L and CP, and fiber content (milk fat depression)

II. Forage Consumption

A. A producing dairy cow can not eat enough forage to meet her nutrient needs during lactation

B. Forage intake may be stimulated by feeding several times / day, and by providing a variety of forages

III. Concentrates

A. Concentrate mixture includes grains, milk feeds, protein supplements and minerals

1. The mixture fed will depend on the forage being fed (low protein forage = high protein concentrate), availability, and cost

2. Amount of concentrate fed will depend on:

-amount of forage consumed

-amount of milk produced

-composition (% fat) of milk produced

3. Limit concentrate to a maximum of 65% regardless of comparative costs; >65% conc. ==> change VFA production ==> decrease fat in milk

B. Intake affected by palatability & time available to consume conc. in the barn or milking parlor

IV. Feeding Guidelines

A. Requirements vary with phase of lactation and gestation

1. Early Lactation

a. Milk production increases rapidly, peaking at 6 to 8 wks (45-60 d) after calving

b. Increase grain intake to meet energy requirements, but avoid excessive levels (< 65% of total DM)

c. Extra dietary protein allows more efficient use of body fat for milk production since cows are usually loosing BW

d. Limit urea to .4 to .5 lb/day

2. Peak Lactation

a. Maximum intake is reached at ~12 to 14 wks and cows should be kept at peak milk production as long as possible.

b. Grain intake may reach 2.5 % BW, forage intake should be at least 1- 1.25% BW to maintain rumen function

c. Feed several times daily

3. Mid- to Late Lactation

a. Milk production is declining, cow is pregnant

b. Match grain intake to milk production; avoid wasteful grain feeding to low producers

c. Avoid over conditioning

4. Dry Period

a. Forage quality not as critical

b. DM intake ~2% of BW

c. ~2 wk before calving increase grain feeding (~1% of BW); helps ¯ ketosis

d. Feed low Ca ration to help prevent milk fever at calving

e. 4 to 8 wk dry period, depending on age & physical condition

5. Consideration

a. Ketosis

- High blood and urine ketone levels

- Low blood sugar

- Depleted glycogen reserve

- Lack of appetite

Just giving glucose will not work in ruminants

Propylene glycol is best, use steroids

High Producing cow ---> Needs glucose for milk --> begins using body fat--> acetoacetic acid,

b -hydroxybutyrate, and acetone --> KETOSIS

Cattle prone can be fed high quality before calving & increase substantially after parturition