Why is genetic likeness

a reason for correlation in P*?

Animals that produce P₁ and P₂

share genes and their effects, this causes a contribution of Rh².

"Correlation among P*"

What causes correlation in P₁ and P₂?

1) shared genetic information

2) environment

What makes pairs of obervations correlated as compared to random pairs of observations?

List two examples

1) Repeated records on cows

2) Records on full sibs

For each unit increase/decrease in _1_, we

predict the average increase/decrease in _2_.

1) P* (phenotypic information)

2) A (breeding value of animal)

What type of information do we use to predict

breeding value of an animal?

phenotypic information

What do we use to predict what happens

on the average?

Regression

"Level of accuracy" is used to do what?

Evaluate how we use different information to

give us response to selection

Define "Level of accuracy"

Correlation between the true breeding value

and the predicted breeding value

Name traits that we wish to improve but

cannot measure on live animals

carcass quality

carcass lean yield

Name traits that we wish to improve but

cannot measure on both sexes.

litter size

milk production

egg production

Name traits expressed by an animal that

can be measured more than once (repeated

over the animal's lifetime)

litter size

lactation yield

racing time

Name traits that are only expressed

once by an animal

birth weight

yearling weight

age at puberty

backfat at 250 lbs

Give the equation for calculating regression

             b_A.P* =  ________n R h²_______

                          1+(n-1) corr. among P*

n = # of records

R = genetic relationship between animal's

breeding value on phenotypic info known

h² = heritability

Give the equation for calulating accuracy

r_A.P* = [b_A.P* x R]^1/2

n = # of records

R = genetic relationship between animal's

breeding value on phenotypic info known

h² = heritability

Explain two ways in which breeding value

can be calculated

1) sum of individual (additive) gene effects

2) twice the difference between mean of a large

number of progeny from large number of mates,

and mean of population

Why is environmental likeness a reason

for correlation in P*?

something that is common to both records, but

not to other records

 Define "permanent environmental variance"

environmental effect that

is "permanent" throughout an animal's life,

affecting each production record

labeled as E_p²

total correlation is h² + E_p²

total correlation can also be called

"repeatability" and the symbol "r_e" can be used

Define "common environmental variance"

environmental effect that is common for all

members of a family

labeled as c²

for full-sib family: .5 h² + c²

for half-sib family: .25 h² + c²

The dairy evaluations regularly solve how many simultaneous equations?

                         A) 30,000

                         B) 300,000

                         C) 3,000,000

                         D) 30,000,000+

D) 30,000,000+

Define E.R.P.A.

Estimated Relative Producing Ability

- predicted deviation for expected

future performance

 Calculate the regression coefficient and accuracy

for a sow, based on her 3 records (she has

produced 3 litters)

                    h²=.12

                    r_e=.26

                    c²=.09 for littermates

                    c²=0 for non-littermates

             b_A.P* =  ________n R h²_______

                          1+(n-1) corr. among P*

=  _(3)(1)(.12)_ =0.24

 1+(3-1)(.26)       

 r_A.P* = [b_A.P* x R]^1/2

= [(0.24)(1)]^1/2 = 0.49

List four benefits of using multiple records

•  inexpensive

• overcome effects of temporary environment

• useful when traits have low h² and r_e

• increases generation length

List benefits of using progeny data

List benefits of using sib data