Cattle herd health nutrition

Question 1

How much energy maintenance does a 650kg cow need per day and how does it increase with lactation/pregnancy

Answer 1

70MJ/day
+ 5MJ per litre of milk given

AT full term gestation, need extra 50MJ/day

Question 2

How much of their own body weight can cows eat

Answer 2

2.5% BW
Or can say 2% + 10% of milk yield

Question 3

Which two fibres are acid detergent and what is minimum level

Answer 3

Lignin and cellulose
Minimum 19%

Question 4

Which additional fibre is just neutral detergent and what is minimum neutral detergent fibre level

Answer 4

Hemicelluloase

Minimum is 21% but really want 30%

Question 5

What two AAs might be rate limiting on milk production

Answer 5

Lysine
Methionine

Question 6

Target body condition generally + through lactation

Answer 6

Generaly want 2.5 - 3.5

At drying off/calving want 3; then can drop down to 2.5 in early lactation and gain back to 3 by late lactatino

Question 7

What metabolic changes do we get in negative energy balance
+ what happens to milk

Answer 7

Increase in NEFAs
Decrease in glucose
Milk increases in butter fat and decreases in protein

Question 8

When is peak milk yield

Answer 8

4-10 weeks post calving
Then falls by 10% per month

Question 9

How are different beef cattle systems fed

Answer 9

Intensive beef fed mostly concentrates, very little fibre; finish in 13 months
18 month beef somewhere between
Grass fed beef takes 23 months to finish; lots of firbre

Question 10

What is the target daily live weight gain in finishing cattle and what is the dry matter conversion

Answer 10

Target gain = 1.3kg per day
Conversion is 10kg food per 1kg gain