SELECTION PART 2

Question 1

What is a challenge in selection?

Answer 1

get a higher accuracy and intensity while decreasing GI

Question 2

How to increase accuracy without taking time and money

Answer 2

• Use all performance records on all relatives
• Use BLUP methods for EBVs
• Incorporate genomic data

Question 3

How to measure improvements?

Answer 3

Plot the response to selection = average EBV per year

Question 4

How can we, animal breeders, make improvements?

Answer 4

Using reproductive technology such as AI and ET

Question 5

2 ways for multiple trait selection

Answer 5

• You Select only for one trait can give you high yield
• Divide among several traits

Question 6

What happens if we select for more traits

Answer 6

Selection intensity for each individual trait will decrease, but make greater improvements overall.

Question 7

More traits gives us more or less response in individual traits

Answer 7

more traits gives less response in individual traits

Question 8

Explain selection pressure on important traits

Answer 8

more selection pressure on important traits –> less pressure on less important –> ignore the worthless ones

Question 9

What are the 4 methods to select animals

Answer 9

• tandem selection
• independent culling levels
• Selection for extremes
• Selection index

Question 10

Selecting 1 trait each generation, alternating traits each generation

Answer 10

Tandem Selection

Question 11

Select for 1 trait for a generation then switch, OR select for 1 trait until you reach a target then switch

Answer 11

Tanden Selection

Question 12

Issue with tandem selection

Answer 12

ignore performance in other trait that may be good since you don’t measure that trait

Question 13

Establish minimum levels of performance for each trait. Animals must meet the minimum for all traits to be selected.

Answer 13

Independent culling levels

Question 14

Often used as part of multi-stage selection - make decisions at stages of the life cycle

Answer 14

Independent culling levels

Question 15

What are the issues with independent culling levels (3 things)

Answer 15

• Translating goals into cutoff points is difficult
• changes of the cutoff must be made if population improves
• Does not allow excellence in one trait to offset poor performance in another trait

Question 16

Select animals with high performance in any one trait, regardless of performance in other traits

Answer 16

Selection for extremes

Question 17

Problem with selection for extremes

Answer 17

Lead to problems in other traits the animal has

Question 18

Combines the performance for the traits into one aggregate number also known as index

Answer 18

Selection Index

Question 19

How would you treat EBVs/EPDS in selection index

Answer 19

you treat the index as an EBV/EPD for selection

Question 20

What is the problem of selection index

Answer 20

The economic value of the trait

Question 21

What is the most important method of selection

Answer 21

Selection Index

Question 22

Multi-Trait Selection

Answer 22

1. Define the economic value for the trait
2. Correlations among the traits

Question 23

Which challenge is the most important to deal with

Answer 23

Define the economic value for the trait

Question 24

What selection method can account for the multi-trait selection problems

Answer 24

Selection index

Question 25

Why use several selection index

Answer 25

to make life easier

Question 26

combination of economically important traits within a production system (it is the end, what you want to achieve)

Answer 26

Selection objective

Question 27

traits based on which animals are chosen (they are the means used to achieve the selection objectives), what are you going to do

Answer 27

Selection criterion

Question 28

The choice of the selection objective will depend on what

Answer 28

who your market is and what you are interested

Question 29

The choice of the selection criteria will depend on 2 things

Answer 29

Its own economic importance/ the traits of economic relevance

The genetic and phenotypic variation that exist in the trait

Question 30

Always thinking about the future

Answer 30

Selection objective: