Animal Breeding Exam 1

Animal Breeding

Selecting sires and dams, assigning them to matings, and producing offspring

Successful breeders/producers will

Consistently produce animals that are desireable and at the lowest cost

Breeders base their decisions off of

Informations and resources such as money, time, feed, offspring data, performance, etc.)

Describing the production system entails

Understanding the dynamics of the industry and consumer demands

What flows down the production system pyramid?

Genetic info gets sent down by operation owners/breeders

What informations flows up the production system pyramid?

Feedback gets sent up by the consumers to help producers make better decisions

As you move down the production system pyramid, the attention shifts from

Individual animals to group averages

Producers can control level of

Integration

What goals do producers need to identify

What breed is needed for what purpose and how to accomodate those goals

What breeding systems to producers have to choose from

Purebreeding, crossbreeding, and composite formation

How do producers estimate genetic parameters

They use offspring data, economic value, and individual data

How do producers design animal evaluation systems?

Take genetic parameters and evaluate things such as:

Cost and return

Accuracy of info

Male vs female emphasis

Impact on next gen

What kinds of traits to producers measure?

Easy traits→Speed of laid eggs

Requires repro→Milk production

Specialized facilities→Feed consumption

Destruction of animals→Carcass info

Animal’s lifetime→ Longevity

How do producers develop selection criteria?

By choosing the best traits, and focus on those traits one gen at a time (Cannot select for everything all at once)

How do producers design mating system

They manage inbreeding, and choose between compensatory or assortative mating

What does it mean for a producer to design a multiplication system?

They decide whether or not they should expand or reduce a herd size and what that would entail

The industry is very sire-focused because

A male’s single ejaculate can produce many offspring and can be transported worldwide

What two tasks does animal breeding require?

1. Selection

2. Mating systems

Phenotype=

Environment+Genotype

Breeding value

Contribution of animal’s genes to its offspring phenotype

How are genotypic value and breeding value different?

Genotypic value contributes to animal’s own phenotype while breeding value contributes to offspring’s phenotype

Heredity

Traits passed down from one generation to the next

Mean performance of a herd can fluctuate due to

Environmental effects and genetic drift

We express genetic values as deviations from the contemporary group mean to

Dampen environmental noise

As the population mean changes

The genetic value of an individual changes as well

An animal that is inferior in one population can be

superior in another population

Gene frequency is going to determine the result/performance of

An entire population

Expected progeny difference

Expected performance of the offspring of a parent, expressed as a mean deviation

Expected progeny difference (EDP)=

½ of the breeding value

Sire’s are evaluated based on

Performance of their progeny

Predicted progeny breeding value=

(Dam BV+Sire BV) / 2

Mules do not have a breeding value because

They do not contribute anything to their progeny

Gene action vs Gene effect

Type of dominance vs Change in phenotype

Only _______ can be transmitted from parent to offspring

Individual alleles, NOT pairs

Dominance effect

The results of the interaction among both alleles at a locus (NOT HERITABLE)

Epistatic effect

One loci acting on another loci

Heritability

Potential for change in a population based on genetic (NOT environment)

Heritability means

No potential for change of a specific alele

Inherited refers to

Genetic control of the phenotype, a type of gene action