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Flashcards in Population Genetics Farm Deck (16)
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1
Q

How does the modern dairy cow differ to an old style of cow?

A

^ milk yield
v fertility
v health
v utility or robustness

2
Q

How do quantitative genetic traits differ from qualittiative?

A

Can be measured, but often based on 1000s of genes which are usually NOT KNOWN
- select based on phenotypic trait not distinct bit of DNA

3
Q

Give 3 types of dairy system

A
  • ^ input/output
  • pasture based
  • niche markets eg. organic, soil association guidelines etc
4
Q

What is a selection index?

A

Multiple traits combined and weighted for importance and interaction between them eg. productivity index = milk yield, fertility etc.

  • often given in terms of monetary value
  • may incoroporate welfare, temperament etc
5
Q

What are EBVs called in the dairy industry?

A

PTA (predicted transmitting ability)

6
Q

What are the majority of dairy cows nnowadays?

A

> 90% holstein only 10% fresian (black and whites)

7
Q

What is PIN?

A

Production index = kg milk, milk fat, protein

8
Q

How is fertility measured in the dairy industry?

A

Calving interval

9
Q

What is £PLI?

A
Profitable Lifetime Index 
- milk PTA
\+ fat PTA
\+ protein PTA
\+ lifespan PTA
- SCC PTA
\+ locomotion PTA
> each will have an associated value, so 1 unit ^ characteristic affects £PLI by x amount
10
Q

How does SCC PTA affect the merit of a bulls £PLI?

A

negative is good!

  • 15% = decrease daughters SCC by 15%
  • SCC good predictor of mastitis
11
Q

How are production, health and fertility traits linked? How does this impact bull choice?

A
  • milk, fat, protein ^ mastitis
  • milk, fat, protein ^ lameness
  • milk, protein ^ fertility CI
  • fat ^ fertility CI
    > want a bull that breaks these correlations as all are negative!!
    > selction index identifies bulls that go against these correlations eg. those with ^ milk yield but v calving interval
12
Q

How is a fertility index formulated?

A

Combine a fertility trait PTA (or multiple traits) with relative economic value eg. FI = -0.31(CI) +1.56(Non-return rate) to give an economic approach to choosing bulls

13
Q

How has the £PLI recently been improved?

A

Broaden the breeding goal - include fertility, revision of economic values [dairyCo], condition score and environmental sensitivity [Robust cows]

14
Q

What outputs are aimed for in the future dairy cow?

A

Milk of the right composition and produced the right way (consumer driven)
Less calves and less cull cows
Imprived welfare and environmental impact
^ profits

15
Q

Why is genetic improvement particularly viable in the dairy industry?

A

AI

16
Q

Give examples of the traits scored for holstein classification process

A
stature
rump width, angle
udder 
milk 
foot angle 
chest width 
temprament