ANS 325 Bundy Exam 2

What does rbv,bv(hat) mean?

How accurate are our EBV predictions, calavulated from (sqrt narrow sense heritablilty)

Intensity value

How many males and females should be kept for mating?

Sigmabv (standard deviation)

How variable is the trait of interest?

L

What length of time does it take to turn over a generations

Can accuracy be negative

No

Selection intensity

number of standard deviations between mean of selected parents and the mean of population; released to the proportion of animals selected out of selection candidates.

Generation interval: L (definition)

Average age of parents when offspring are born

L is calculated

L = (summation of age)(number of animals)/number of animals

Direct Response to Selection

Genetic Change in a trait resulting from the selection of that trait

Phenotypic Correlation (rx,y)

Measure of strength of relationship between phenotypic value in one trait and the phenotypic value in another trait

Correlated response to selection

Gentic change in one or more traits resulting from selection in another

Linkage

How closely genes are located on the chromosome

What is the effect if two traits are located close together

Tend to stick together through recombination

Pleiotropy

A phenomenon of a single gene affecting more than one trait

Pleiotropy example

Selecting for WW, can affect BW and YW

Indirect response to selection

selection for x as means of improving Y

Own Performance Data

information on individuals’ own phenotypes and genotypes

How is performance data collected on animas

at birth animals are tagged, this tag is then read at scales to track growth and consumption

What pulls progeny, performance, and pedigree data together

BLUP

Pedigree data

information on the genotypes or performance of ancestors or collective relatives of an individual

Progeny data

Information on the genotype or performance of descendants of an individual

Statistical Models

A mathematical representation of animal performance that includes various genetic and environmental effects and is used for genetic prediction

Direct Component

Effect of an individual’s genes on its performance

Maternal Component

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

BLUP is used for

Nucleus operations or large scale genetic evaluations

Confidence Range

Range of values within we expect that a true value of interest lies

Standard error of prediction

indicates the potential amount of future change in a prediction

Multiple Trait selection

Placing direct slection pressure on more than one rain

Net Merit

A value that represents an individual’s genetic merit across more than one trait

Tandem Selection

Selection for one trait for a period of time followed by selection for a second trait

Can tandem selection be used when traits are favorably correlated

no, if traits are not favorably correlated then improvement in one trait will result in poor performance in another trait.

Independant colling levels

Minimum stands for traits undergoing multiple trait selection

Economic Selection index

An index or combination of weighting factors and genetic information on more than one trait

Economic Weight

Change in profit expected for a unit of change in each of the traits

3 general methods for multitrait selection

1) tandem Selection

2) Independent culling levels

3) selection index