SELECTION PART 1 Flashcards
What are the main tools for animal breeder
- Selection
- Mating Systems
- Animal Disposal
Decide which animals become parents of the
next generation
Selection
Decide which animals are mated to each
other
Mating Systems
Remove animals based on current performance (i.e., remove the worst ones, to improve the
current herd).
Animal Disposal
The controlling of reproduction of individuals within a population
Selection
What are the two types of selection
Natural Selection and Artificial Selection
not imposed by man
Natural selecction
imposed by man
Artificial Selection
What are the two types of natural selection
Absolute selection and Partial Selection
What is absolute selection
Lethal phenotypes and sterility
What is partial selection
Reduced viability and competition for mates
Is artificial selection faster or slower than natural selection
faster than natural selection
Why is it important select for a balanced animal when doing artificial selection
Artificial selection can be taken to extremes meaning selection for extremes performance in one trait can result in loss of fitness
Why be aware of natural selection?
Animal can be born naturally born with a genetic diseases with the addition of artificial selection that can really harm the animal.
Example: White color desirable for some breeds. but there is a lethal white gene
Applied to potential parents to control the genotype of their offsprings
Selection
A force to change the FUTURE value of the herd
selection
What are future offsprings
heritability and EBV
Applied to animal currently in the herd. Not allowing them to have another production cycle
Animal Disposal
A force to change the CURRENT value of the herd
Animal Disposal
What are the current production
R and MPPA
culling for production and economic reasons.
Voluntary culling
Are most culling voluntary or involuntary?
involutary
Does Culling remove individuals as parents?
Yes
What do you look at when you make selections
Look at Breeding value or EPD
What do you look at when you make culling decision
MPPA
Looks at next production cycle
MPPA
Intensity depends on % selected which depends on 3 things
- Reproductive Rate
- Generation Interval
- Number of replacements needed/parents (NR)
Explain the relationship between selection animals, selection intensity and selection pressure
Selecting less animals increases the selection intensity, increases selection pressure
Selecting more animals decreases the selection intensity, decreases selection pressure
What affects change in genetic response per year
- Heritability and variation
- accuracy of selection
- selection intensity
- generation interval
How do we increase genetic response per year
- Increase accuracy of selection
- Increase selection intensity
- Decrease generation interval
- Decrease heritability and variation
