Dairy Flashcards
1
Q
What are the goals of selective breeding in dairy cattle?
A
- Increase profitabiliaty of animals, not compromising welfare
- Increased returns from milk, calve sale and cull cows
- Decrease feed cost
- Decrease vet bills
2
Q
What are the signs oestrus displayed by cattle?
A
- Standing to be mounted
- Mounting other cows head to head
- Cows grouping together
- Rub marks on tailhead, rump, flanks
- Bellowing
- Restlessness
- Clear discharge (bulling string)
- Slight increase in temp and decrease in milk yield
3
Q
Describe the lifecycle of the average dairy cow
A
Day 0 - born, removed from mother < 24hrs
Day 35 - weaned
Reared for another 420 days
14-15 months old - bred
280 day gestation
60 days prior to calving dry off
About 2 years old - calves
85 days later - back in calve
*ideally calves at 1 yr intervals*
Generally have 4-5 lactations then culled
4
Q
Draw a typical lactation curve for a dairy cow
A
5
Q
What are the traits selected for in dairy cows?
A
- High milk yield
- Good conformation
- Good feet
- Good fertility
6
Q
When choosing a beef bull to put on dairy cows, what do you select for?
A
- Easy calving - Angus > Limousin > Charolais
- Personal preference
7
Q
When choosing a dairy bull, what traits do you look for?
A
- Progeny tested bulls - Test performance of a bull’s heifers relative to genetic base; expressed as predicted transmitting ability (PTA)
- Health
- Longevity
- Fertility
- Productivity
8
Q
What are the major reasons for culling a diary cow?
A
- Lameness
- Low productivity
- Mastitis
- Poor fertility
- Poor conformation
9
Q
A
