ANSC 4395 FINAL EXAM 3 LATEST
UPDATE 2025/2026 GRADED A+
Selection - correct answerThe practice of allowing certain individuals more opportunity
to reproduce than others.
Only means of making genetic improvement in a closed population.
Improvement made by increasing the frequency of desired genes.
Results of selection are predictable in magnitude and direction.
Response to selection - correct answerProgress resulting from selection is called
response.
Genetic change that occurs as a result of selection.
Ex. If environmental conditions have remained constant, the phenotypic change should
mirror the genetic change.
selection differential - correct answerthe difference between the mean performance of
the selected individuals and the average of the entire herd.
Generation Interval - correct answerThe length of time it takes to replace the members
of on generation in a herd.
Symbolized by: L
Breeding Value - correct answerAn individual's phenotype is the result of its genetic
merit and the effect of the environment.
Estimated Breeding Value (EBV) - correct answerActual breeding value of an individual
is never known.
Can be estimated from an individual's performance and the performance of its relatives.
Addition of information from relatives will always increase confidence in an estimate of
breeding value.
Individual's own performance - correct answerSingle most important price of into for
estimating breeding value.
Accuracy can be increased by measuring progeny or sibs.
Measuring relatives cannot take the place of measuring the individual itself until
numerous records on relatives have been obtained.
Multiple records on an individual - correct answerSome traits measured several times
during and animal's lifetime.
Ex. egg production, milk production, litter size, litter weight.
IF a trait is measured several times, each value should be used in an estimate of
breeding value.
, Sib information - correct answerAlmost any animal will have siblings.
Limited number of full sibs (usually litter-bearing species).
Frequently, a large number of half sibs in any herd.
Full sibs - correct answer1/2 genes in common
half sibs - correct answer1/4 genes in common
Progeny Testing - correct answerOne of the most powerful means of estimating
breeding value.
Using AI, an individual may have several hundred or thousands of offspring.
Embryo transfer allows for considerable accuracy in females as well.
Pedigree Selection - correct answerTraditionally, livestock have been evaluated based
on the merits of their ancestors.
Sire, dam, and grandparents provide additional information for estimating BV.
Multiple Trait Selection - correct answerEfficiency of livestock production is seldom
determined by a single trait.
If there are multiple objectives, there should be multiple criteria for selection.
Any trait that is economically important should be considered for inclusion in selection
media.
Tandem Selection - correct answerOnly one trait is considered at one time.
After it is improved sufficiently, another trait is considered by itself.
Considerable selection pressure can be exerted on the trait under consideration at a
particular time, but the final result maybe little improvement in net merit of the herd.
Independent Culling Level - correct answerAll important traits are considered together.
A minimum level of performance is established for each trait.
Any animal that does not meet the minimum for every trait is eliminated.
Animals that are deficient in one trait, but superior in all others will be culled.
Selection Index - correct answerMost efficient procedure for improving several traits at
once.
Takes into account heritabilities, genetic and phenotypic correlations, standard
deviations, and economic values for all traits.
Marker Assisted selection - correct answerAllows for the selection of specific DNA
variations that have a measurable difference or an effect on complex traits.
Ex. Coat color, genetic defects or simply inherited traits, Carcass quality, quantity yields,
Palatability attributes, Milk production, Growth performance, Fertility/reproductive
efficiency.
Tested using hair, tissue, semen, or blood samples to analyze DNA.
Is a tool to increase accuracy of selection.
UPDATE 2025/2026 GRADED A+
Selection - correct answerThe practice of allowing certain individuals more opportunity
to reproduce than others.
Only means of making genetic improvement in a closed population.
Improvement made by increasing the frequency of desired genes.
Results of selection are predictable in magnitude and direction.
Response to selection - correct answerProgress resulting from selection is called
response.
Genetic change that occurs as a result of selection.
Ex. If environmental conditions have remained constant, the phenotypic change should
mirror the genetic change.
selection differential - correct answerthe difference between the mean performance of
the selected individuals and the average of the entire herd.
Generation Interval - correct answerThe length of time it takes to replace the members
of on generation in a herd.
Symbolized by: L
Breeding Value - correct answerAn individual's phenotype is the result of its genetic
merit and the effect of the environment.
Estimated Breeding Value (EBV) - correct answerActual breeding value of an individual
is never known.
Can be estimated from an individual's performance and the performance of its relatives.
Addition of information from relatives will always increase confidence in an estimate of
breeding value.
Individual's own performance - correct answerSingle most important price of into for
estimating breeding value.
Accuracy can be increased by measuring progeny or sibs.
Measuring relatives cannot take the place of measuring the individual itself until
numerous records on relatives have been obtained.
Multiple records on an individual - correct answerSome traits measured several times
during and animal's lifetime.
Ex. egg production, milk production, litter size, litter weight.
IF a trait is measured several times, each value should be used in an estimate of
breeding value.
, Sib information - correct answerAlmost any animal will have siblings.
Limited number of full sibs (usually litter-bearing species).
Frequently, a large number of half sibs in any herd.
Full sibs - correct answer1/2 genes in common
half sibs - correct answer1/4 genes in common
Progeny Testing - correct answerOne of the most powerful means of estimating
breeding value.
Using AI, an individual may have several hundred or thousands of offspring.
Embryo transfer allows for considerable accuracy in females as well.
Pedigree Selection - correct answerTraditionally, livestock have been evaluated based
on the merits of their ancestors.
Sire, dam, and grandparents provide additional information for estimating BV.
Multiple Trait Selection - correct answerEfficiency of livestock production is seldom
determined by a single trait.
If there are multiple objectives, there should be multiple criteria for selection.
Any trait that is economically important should be considered for inclusion in selection
media.
Tandem Selection - correct answerOnly one trait is considered at one time.
After it is improved sufficiently, another trait is considered by itself.
Considerable selection pressure can be exerted on the trait under consideration at a
particular time, but the final result maybe little improvement in net merit of the herd.
Independent Culling Level - correct answerAll important traits are considered together.
A minimum level of performance is established for each trait.
Any animal that does not meet the minimum for every trait is eliminated.
Animals that are deficient in one trait, but superior in all others will be culled.
Selection Index - correct answerMost efficient procedure for improving several traits at
once.
Takes into account heritabilities, genetic and phenotypic correlations, standard
deviations, and economic values for all traits.
Marker Assisted selection - correct answerAllows for the selection of specific DNA
variations that have a measurable difference or an effect on complex traits.
Ex. Coat color, genetic defects or simply inherited traits, Carcass quality, quantity yields,
Palatability attributes, Milk production, Growth performance, Fertility/reproductive
efficiency.
Tested using hair, tissue, semen, or blood samples to analyze DNA.
Is a tool to increase accuracy of selection.
