Animal Breeding Systems

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Animal Breeding Systems Animal Breeding Systems

Unit 12Unit 12



Systems of BreedingSystems of Breeding

Two basic systemsTwo basic systems

± ± Straight breedingStraight breeding

± ± crossbreedingcrossbreeding System used depends on:System used depends on:

± ± Kind of livestockKind of livestock

± ± Size of the herdSize of the herd ± ± Amount of money available Amount of money available

± ± Goals of the farmer or rancher Goals of the farmer or rancher



Systems of BreedingSystems of Breeding

Straight breeding:Straight breeding:

± ± Purebred breedingPurebred breeding

± ± InbreedingInbreeding ± ± OutcrossingOutcrossing

± ± Grading upGrading up

Crossbreeding:Crossbreeding:

± ± TwoTwo--breed crossesbreed crosses ± ± ThreeThree--breed crossesbreed crosses

± ± Rotation breedingRotation breeding



Purebred BreedingPurebred Breeding

Purebred animal:Purebred animal:

± ± Animal of a particular breed Animal of a particular breed

± ± Characteristics of the breed to which it belongsCharacteristics of the breed to which it belongs ± ± Both parents mast have been purebredBoth parents mast have been purebred

Color markings is the most commonColor markings is the most common

disqualificationdisqualification



Purebred AnimalsPurebred Animals

Not necessarily better than nonpurebredNot necessarily better than nonpurebred

Undesirable recessive characteristics mayUndesirable recessive characteristics may

appear because of the homozygosity of theappear because of the homozygosity of thegenesgenes

The average purebred animal is generallyThe average purebred animal is generally

better than the average nonpurebred animalbetter than the average nonpurebred animal



InbreedingInbreeding

Mating of related animalsMating of related animals

Close breedingClose breeding-- most intensivemost intensive

LinebreedingLinebreeding-- distantly related animalsdistantly related animals

Increases the genetic purity of the stockIncreases the genetic purity of the stock

produced.produced.

Undesirable and desirable genes becomeUndesirable and desirable genes becomegrouped together in the offspring withgrouped together in the offspring with

greater frequency and more visible.greater frequency and more visible.



OutcrossingOutcrossing

Mating of animals of different families withinMating of animals of different families within

the same breedthe same breed

Bring into the breeding program traits thatBring into the breeding program traits thatare desirable but no present in the originalare desirable but no present in the original

animalsanimals

Linecrossing is mating animals from twoLinecrossing is mating animals from twodifferent lines of breeding within a breeddifferent lines of breeding within a breed



Grading upGrading up

Mating of purebred sires to grade femalesMating of purebred sires to grade females

A grade animal in any animal not eligible for A grade animal in any animal not eligible for

registryregistry Some breed associations do permit theSome breed associations do permit the

offspring of grading up to be registered.offspring of grading up to be registered.



CrossbreedingCrossbreeding

Mating of two animals from different breedsMating of two animals from different breeds

Offspring is a hybridOffspring is a hybrid

Superior traits from crossbreeding are calledSuperior traits from crossbreeding are calledhybrid vigor or heterosishybrid vigor or heterosis

Animals selected for use in a crossbreeding Animals selected for use in a crossbreeding

program must have the desired traitsprogram must have the desired traits



Crossbreeding systems for beef Crossbreeding systems for beef

General considerationsGeneral considerations

± ± Good recordkeepingGood recordkeeping

± ± Calving difficulties may increaseCalving difficulties may increase

± ± Fewer calving problems if large breed dams are usedFewer calving problems if large breed dams are used

± ± Large breed dams have higher maintenance costsLarge breed dams have higher maintenance costs

± ± AI allows access to better bulls AI allows access to better bulls

± ± More than one breeding pasture may be requiredMore than one breeding pasture may be required



Crossbreeding systems for beef Crossbreeding systems for beef

Terminal sire crossed with F1 femalesTerminal sire crossed with F1 females

Rotate herd bull every three or four yearsRotate herd bull every three or four years

TwoTwo--breed rotationbreed rotation ThreeThree--breed rotationbreed rotation

Four Four-- and Fiveand Five--breed rotationbreed rotation

Static terminal sire systemStatic terminal sire system



Crossbreeding systems for swineCrossbreeding systems for swine

Select breeds that meet the objectivesSelect breeds that meet the objectives

Select breeds that produce large litter and heavier Select breeds that produce large litter and heavier

weaning weightsweaning weights

Select breeds that have less backfat and high rateSelect breeds that have less backfat and high rate

of gainof gain

Sows used should be 50% Chester White,Sows used should be 50% Chester White,

Landrace, or YorkshireLandrace, or Yorkshire Select boars from sows in the top 25% of a herdSelect boars from sows in the top 25% of a herd

Crossbred boars maybe usedCrossbred boars maybe used



Crossbreeding systems include:Crossbreeding systems include:

Rotational crossbreedingRotational crossbreeding

Terminal crossing systemTerminal crossing system

Rotaternimal systemRotaternimal system



Crossbreeding systems for sheepCrossbreeding systems for sheep

RotationalRotational

RotoRoto--staticstatic

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Animal Breeding Systems