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8/3/2019 Animal Breeding Systems
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Animal Breeding Systems Animal Breeding Systems
Unit 12Unit 12
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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
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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
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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
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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
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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.
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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
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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.
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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
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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
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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
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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
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Crossbreeding systems include:Crossbreeding systems include:
Rotational crossbreedingRotational crossbreeding
Terminal crossing systemTerminal crossing system
Rotaternimal systemRotaternimal system
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Crossbreeding systems for sheepCrossbreeding systems for sheep
RotationalRotational
RotoRoto--staticstatic