Ch 14avs 3305

Question 1

What are some ways to increase accuracy?

Answer 1

Increase heritability of traits
•Managing animals more uniformly •Adjusting for known environmental effects •Using contemporary groups
• Etc

Question 2

What is the key to genetic prediction ?

Answer 2

Improving accuracy

Question 3

What are the two genetic prediction methods?

Answer 3

1. Selection index
2. Best linear unbiased prediction (bLup)

Question 4

Define selection index

Answer 4

A linear combination of phenotypic information and weighing factors used for genetic prediction when performance data come from genetically similar contemporary groups

(Best used1 fit for individual animal prediction)

Question 5

What equation used for selection index?

Answer 5

I= B1x1+B2x2+B3X3…Bnxn

Question 6

I=

Answer 6

Index or genetic prediction

Question 7

Bi =

Answer 7

A weighing factor

Question 8

Xi =

Answer 8

A single item of phenotypic information - a performance record or the average of a group performance records.

Question 9

N=

Answer 9

The total number of items of phenotypic information

Question 10

What are the three sources of phenotypic information? (selection index )

Answer 10

1.own performance data
2. Pedigree data
3. Progeny data

Question 11

What is the strategy of using selection index?

Answer 11

1. Identify the selection index of most relevance
2. Rank animals on the selection index
3. Consider individual EBVs of importance
4. Consider other traits of importance

Question 12

Define Best linear unbiased prediction (b Lup)

Answer 12

A genetic prediction method used when performance data is coming from genetically diverse contemporary group:
‘

Used for population data( better used for large scale genetic evaluation

Question 13

What are the four models of best Linear unbiased prediction?

Answer 13

1. Animal model
   2, sire model
2. Single trait model
3. Multiple trait model

Question 14

Animal model

Answer 14

Used to evaluate all animals in a population

Question 15

Sire model

Answer 15

Used to evaluate only sires

Question 16

Single trait model

Answer 16

Not as complex

Question 17

Multiple trait model

Answer 17

Use genetic correlations between traits to determine BV for certain traits that are correlated
•Example: There are more weaning weight data available than birth weight field data. Both data are incorporated in BLUP model.
☛ Weaning weight information helps predict birth weight and vice versa.

Question 18

What are the genetic components of Best linear unbiased prediction? 1,

Answer 18

1. Direct
2. Material
3. Paternal

Question 19

Direct

Answer 19

The effect of an individuals gene on its performance

Question 20

Maternal

Answer 20

The effect of genes in the dam of an individual that influence the performance of individual through environment provided by dam

Question 21

Paternal

Answer 21

Same as maternal but for male parents
• Very rare in production species
• Males have little to do with upbringing of progeny

Question 22

Example of a trait with both direct and maternal components

Answer 22

Weaning weight:
Determined by animal’s own genes involved in growth (direct component). However, also influenced by milk production and mothering ability and these are influenced by maternal genes (maternal component).

Question 23

EXTREMELY COMPLEX PROGRAM!!

Answer 23

Involves iterations of data, sometimes running a single model for several days

Question 24

Simply stated:

Answer 24

Accounts for differences in mean breeding value for contemporary groups

Question 25

Large Scale genetic evaluation

Answer 25

Definition; The genetic evaluation of large populations- typically entire breeds.

Application of BLUP (Best Linear Unbiased Prediction) to entire breeds
•Allow for comparison of animals within different herd •Speeds the rate of genetic change

Question 26

Central test

Answer 26

Test (experiment) designed to compare performance of young animals (males) from different herds for various traits of importance.
•Bring the animals to one location and fed for a period of time then compare the performance.

Question 27

Designed Test:

Answer 27

Carefully monitored progeny test designed to eliminate sources of bias

Question 28

Field Data:

Answer 28

Data reported by individual breeders to breed associations

Provides huge amount of info
(US Beef ~100.0 million; cow-calf operation ~900,000) (US Dairy ~9.4 million; dairy operation ~60,000) (US Horse ~9.2 million; people own horses ~2,000,000)
⇣
Lead to BLUP analysis

Question 29

Sire Summaries

Answer 29

The most visible product of large-scale genetic prediction
A list of genetic predications, accuracy values and other valuable information about sires in a breed

Question 30

Why not dam summaries?

Answer 30

Male selection is much more important because of its effectiveness in rate of genetic change in a population.
. Sire from someone else are more accessible than dams.

Question 31

Types of EPD’s

Answer 31

Parent EPD:

Nonparent EPD:

Interim EPD:

Question 32

Parent EPD

Answer 32

EPD for any animal with progeny data includes accuracy values.
•EPDs published in the sire summaries are example.

Question 33

Nonparent EPD:

Answer 33

EPD for animal without progeny data, typically does not included accuracy values.
•This is more of pedigree estimate; average of EPD of sire and dam.

Question 34

Interim EPD:

Answer 34

BLUP analyses are typically months to year apart. •Updated EPD that is calculated between BLUP analysis

Question 35

Meaning of Zero:

Answer 35

Every breed has a set base year or zero value associated with EPD’s that it calculates
•Average EPD for all animals born in base year = 0

Question 36

Why Across breed EPD?

Answer 36

To make fair comparison.

Question 37

Across breed EPD limitations

Answer 37

Lack of accuracy calculations. •Hybrid vigor or heterosis differences •Change annuals so need to stay current