Principles of dairy cow feeding

Question 1

Describe homegrown forages as a diary cow diet

Answer 1

Cheaper
can vary
good fibre supply

Question 2

Describe purchased feeds as dairy cows diets

Answer 2

More nutrient dense
more consistent
more expenise

Question 3

How much does a lactating cow eat in a day?

Answer 3

20-25 kg dry matter per day

Question 4

How much does a dry cow eat per day?

Answer 4

~12-16kg dry matter per day

Question 5

Describe total mixed ration feeding

Answer 5

All concentrate feed is mixed with forage and fed with ad lib access
All cows in same group get exactly the same each day

Question 6

Describe individual feeding systems of dairy cows

Answer 6

Ad lib access to either sample forage or mixed ration of forage plus concentrate
Additional concentrate fed via milking parlour or out-of-parlour feeding stations
More scope to tailor ration to specific cow
Can => concentrate feed is in 2 large meals

Question 7

What are the effects of negative energy balance on dairy cows

Answer 7

Reduced milk quality
Decreased fertility
Impaired immune function (=> metritis, mastitis)
Role in other disease e.g. LDA

Question 8

How can you prevent negative energy balance via feed in dairy cows?

Answer 8

miximise feed intake pre and post calving
Formulating appropriate pre and post calving diets:
- easy to over-feed during dry period
- need high energy density after calving

Question 9

Describe hypocalcaemia in dairy cows

Answer 9

Sudden increase in Ca demand at calving => hard to mobilise stores rapidly => blood Ca conc can fall => skeletal and smooth muscle cannot contract properly

Question 10

How can hypocalcaemia be prevented via feeding in dairy cow?

Answer 10

Feeding in last 3wks pre-calving:
DCAB manipulation
Calcium restriction
targeted supplementation

Question 11

how is rumen acidosis prevented via feeding?

Answer 11

good feed intake to supply energy (rather than high energy density)
Sufficient ‘long’ fibres
Avoid large concentrate (starchy) meals