abg finals

What are quantitative traits also known as?

Multifactorial traits

Which of the following is NOT considered an environmental factor affecting trait expression?

Gene mutations

Which type of trait is described by discrete phenotypes?

Threshold trait

What does QTL stand for?

Quantitative Trait Loci

What is heritability a ratio of?

Genetic variance to phenotypic variance

What does a heritability value of 0.5 indicate?

50% of the phenotypic variance is attributable to genetic variance

What does EBV stand for in animal breeding?

Estimated Breeding Value

In the formula for estimating BV using one parent's phenotypic information, the regression coefficient equals:

Half of the heritability

What does GxE interaction imply?

Performance differences between genotypes change across environments.

Which graph indicates a scaling effect in GxE interaction?

Diverging lines

What is the only genetic variance component that can be estimated directly from population records?

Additive variance

What is the relationship between heritability and phenotypic variance?

Direct

Which term describes the performance outcome of genotypes in specific environments?

Reaction norm

What is the effect of increasing the generation interval in breeding programs?

Slows down genetic progress

What is the primary purpose of a breeding program?

Develop or improve specific traits

Which selection strategy focuses on extreme fractions of individuals?

Directional selection

In tandem selection, what is prioritized?

One trait at a time

What is a critical drawback of independent culling levels?

Animals failing one standard are rejected.

What is hybrid vigor also known as?

Heterosis

What is the purpose of rotational crossbreeding?

Maintain hybrid vigor

What type of hybrid vigor is seen when crossbred dams show improved mothering ability?

Maternal

What is a key advantage of open nucleus breeding systems?

Reduced inbreeding risk

What is an effect of positive assortative mating?

Faster genetic progress

What is corrective mating used for?

Correcting faults in parents

Which of the following defines inbreeding?

Mating more related individuals than average

What is the primary goal of outbreeding?

Enhance hybrid vigor

Which of the following is a key factor affecting genetic progress?

Accuracy of selection

What is the primary goal of genetic evaluation in breeding programs?

Predict breeding values of animals

What does BLUP stand for?

Best Linear Unbiased Prediction

Which type of selection considers economic weights for traits?

Economic selection index

What heritability value is considered low?

<0.2

What is additive variance primarily associated with?

Breeding value

What describes variance caused by interactions between genes at different loci?

Interaction variance

What is the opposite of inbreeding?

Outbreeding

What is the purpose of linebreeding?

Maintain a degree of relationship to an ancestor

What type of mating selects animals with complementary traits?

Corrective mating

What is a dispersed breeding system characterized by?

Animals being selected among production animals

In centralized breeding systems, what is a characteristic of the nucleus layer?

Accurate pedigree records

What is the main drawback of closed nucleus breeding?

Decreased genetic diversity

What is pleiotropy?

Influence of multiple traits by one gene

Which correlation indicates that an increase in one trait results in a decrease in another?

Negative correlation

What example best illustrates favorable negative correlation?

Backfat thickness and loin eye area

Which trait in cattle has the highest heritability?

Stature

In pigs, which trait is moderately heritable?

Growth rate

Which poultry trait has high heritability?

Egg weight

What does high heritability (>0.4) suggest in a trait?

Trait expression is primarily due to additive genetic effects.

What heritability range is typical for reproductive traits in farm animals?

<0.2

Which of the following is an example of a trait with low heritability?

Survival rate

What is the advantage of artificial selection over natural selection?

Ensures traits unrelated to fitness are passed on.

Which selection method prioritizes multiple traits simultaneously?

Economic selection index

What is a major risk associated with intense selection?

Loss of genetic diversity

Which type of selection maintains intermediate trait values?

Stabilizing selection

What is the purpose of progeny testing in genetic evaluation?

Estimate the additive genetic effect from offspring performance.

Which source of genetic evaluation information is most accurate?

Progeny records

What genetic evaluation method adjusts for environmental differences?

BLUP

What is a primary goal of crossbreeding systems?

Minimize inbreeding depression

Which crossbreeding system involves alternating sire breeds across generations?

Rotational crossbreeding

What is hybrid vigor measured by?

Difference between crossbred and purebred trait performance.

What does dominance variance represent?

Interaction of alleles at one locus

What is genotype-environment covariance?

Correlation between breeding value and environmental quality

What term describes the contribution of maternal factors to phenotypic variance?

Maternal effect variance

What is an example of corrective mating?

Pairing animals with complementary traits

What is the main purpose of outbreeding?

Increase hybrid vigor

What type of mating is designed to maintain a relationship with a specific ancestor?

Linebreeding

What is a significant drawback of inbreeding?

Increased homozygosity

Which mating strategy results in intermediate trait performance?

Negative assortative mating

What is the primary cause of genetic correlation?

Pleiotropy

Which example demonstrates a favorable genetic correlation?

Backfat thickness and loin eye area

Why are phenotypic correlations useful in breeding programs?

They allow indirect selection for correlated traits.

What does a correlation value of -1 indicate?

Perfect negative correlation

Which factor directly affects the rate of genetic change?

Generation interval

How does increasing selection intensity affect genetic progress?

Speeds up genetic improvement.

What is a drawback of reducing the generation interval?

Decreased selection accuracy.

Why is heritability essential for breeders?

It predicts response to selection.

What is repeatability in heritability estimation?

Association between multiple measurements in the same animal.

What is the macro-level goal of a breeding program?

Address national agricultural policy and market demands.

Why are farmers important in breeding programs?

Their involvement aligns breeding goals with practical needs.

What is the main purpose of BLUP in breeding programs?

Adjust for systematic environmental effects.

Which type of trait is usually associated with high genetic variation?

Morphological traits.

Which is an example of a moderately heritable trait in poultry?

Egg weight.

What is the primary objective of a food-producing animal breeding program?

Improve production traits for food security.

Which breeding program level focuses on traits within specific environments?

Micro-level.

What type of trait improvement requires long-term genetic development?

Production traits.

What is a key advantage of a terminal crossbreeding system?

Optimizes hybrid vigor for market animals.

What is required to achieve rotational crossbreeding benefits?

Consistent sire rotation.

Which factor is considered a fixed environmental effect?

Seasonal differences.

How do maternal effects influence traits?

Via the maternal environment provided.

What is a common outcome of inbreeding depression?

Reduced fertility and survival.

What does hybrid vigor primarily benefit?

Fitness and reproductive traits.

Which selection strategy works best for traits with intermediate optima?

Stabilizing selection.

What is the main benefit of independent culling levels?

Allows for selection at different life stages.

In stepwise selection, what happens after the first selection stage?

Selected animals proceed to the next stage.

What heritability value is typical for production traits in farm animals?

Moderate (0.2-0.4).

What is the significance of heritability in artificial selection?

It determines response to selection.

What makes BLUP a preferred evaluation method in breeding programs?

Adjustment for systematic environmental effects.

Which genetic evaluation technique is ideal for low-heritability traits?

Progeny testing.

What is the relationship between genetic variation and selection progress?

Directly proportional.

What is the primary objective of tandem selection?

Focus on one trait at a time.

Why is pedigree information important in genetic evaluation?

It provides early genetic potential estimates.

Which factor is crucial in designing a breeding program?

Clear definition of breeding objectives.