Associate Professor Dept of Genetics and Animal Breeding FANSVM Babugonj Barishal Mating different species Mating different breeds Mating the same breed Species crossinghybridization ID: 1026082
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1. Breeding SystemRipon Chandra Paul, PhDAssociate ProfessorDept. of Genetics and Animal BreedingFANSVM, Babugonj, Barishal
2. Mating different species Mating different breedsMating the same breed Species crossing/hybridization1. Cross breeding- I. Back crossing II. Criss-crossing III. Rotational crossingMating relatives-InbreedingClose breeding Line breeding2. Out crossing Mating un-relatives-Out breedingMating likesMating unlikes3. Grading Up4. Lauprecht systemBreeding SystemMatingThe act of pairing a male and female for reproductive purposes. In biology, mating is the pairing of opposite sex for copulation and in social animals, also to raise their offspring.
3. Species crossing/hybridization zoological and genetic engineering interest For example- Mule a cross between the jack (male) of ass species and the mare of the horse species to produce the mule. Horse (64 chromosomes) × Ass (62 chromosomes) :Mule (63 chromosomes) Cattle × Buffalo : Beefalo (Canada, USA) Ass × Zebra: Asbra (Africa)
4. Crossbreeding It involves mating animals of different breeds, lines or species or is the mating of animals from different established breeds. Advantages To improve the overall efficiency of a production system by crossing breeds which have high genetic merit in different traits (Complementarity). To produce individual animals of intermediate performance between that of two more extreme parent breeds. For grading up to a new breed or strain. As an intermediate step in the creation of new synthetic or composite breed. To introduce new variation to numerically small breeds. To introduce a single gene for a favorable characteristics to an existing breed (Introgression). To exploit heterosis or hybrid vigor.
5. Disadvantages Breeding merit of cross-bred animals may be slightly reduced because of the heterozygous nature of their genetic composition. Tendency to break up established characters and destroy combinations of characters..
6. BreedSpeciesComponentsLocationSanta GertrudisCattleShrthorn/BrahmanUSALuingCattleShort/HighlandScotlandAustralian Milking ZebuCattleJersey/ZebuAustraliaJamaica HopeCattleJersey/Sahiwal/HolsteinJamaicaBrangusCattleAngus/BrahmanUSACharbrayCattleCharolais/BrahmanUSASiboney de CubaCattleHolstein/ZebuCubaBeefmasterCattleShorthorn/Hereford/BrahmanUSADroughtmasterCattleShorthorn/BrahmanAustraliaColbredSheepEast Friesland/Clun Forest/Border Leicester/ Dorset HornEnglandFinn-DorsetSheepFinnish Landrace/ Dorset HornEnglandSynthetic or composite breed
7. A crossbred offspring is bred back to one of its parents, which are usually purebred. Crossbred females are mated to males of one of the parental breeds.Back crossing
8. Crisscrossing This system of crossbreeding logically follows the two breed cross. Crossbred F1 females are kept for breeding and are mated to non-related males from one or the other of the two original pure breeds used in the two breed cross.
9. Rotational crossbreeding It is a breeding system where in every step a new sire is introduced i.e. new germplasm is being transferred in every generation. This kind of breeding mostly performed in pig breeding.
10. The Lauprecht System This system was put forward by a German scientist-Lauprecht in 1961. This system essentially consists of a crossing program using three breeds.i.e. A, B and C
11. Grading up Where one breed is changed (Grade up) to another by continued crossing.
12. Out crossingOut crossing is the mating of animal’s that are less closely related than the average of the population from which they come, and opposite to close breeding or is the mating of unrelated animals within a breed. It is the standard method of increasing variation both phenotypic and genetic in the population. Heterozygosity is increased. General fitness and adaptation of the animal to its environment are improved. Crossing with a view to exploitation and adaptation of extraneous genes in a herd or population.
13. Advantages 1. Pure breeds can be obtained just after a few generations (after 7th to 8th generations).2. The start can be made with a little money in comparison to the purchase of an entire herd of purebreds.3. It helps to prove the potentialities of the sire and adds to its market value.4. It is a good start for new breeders who can slowly change over to pure breed systems.
14. Disadvantages Pure breeds are not always better than grade or country animals for the use to be made of them. Pure breed stocks which give good results in one set of environmental conditions do not always give favorable results in some different environmental set up. The pure breed dairy cattle from temperate zones often degenerate when used in tropical areas. Moreover, their offspring fail to show vigor and constitution for high reproduction.
15. Inbreeding is a mating system in which individuals mated are more closely related than the average of the population from which they come. It means the mating of males and females which are related. Animals deemed to be related only when they have one or more ancestors in common on the first 4-6 generations of their pedigree. The intensity of inbreeding depends upon the degree of relationship. In breeding makes more pairs of genes in the population homozygous. Inbreeding
16. Possible use of inbreeding Inbreeding may be used to determine the actual genetic worth of individual. Inbreeding can be used in a practical way to select against a recessive gene that is of economic importance. Inbreeding may be used to form distinct family within a breed, especially if selection is practiced along with it. Inbreeding should be used only for the production of seed stock. The most practical use of inbreeding at the present time is to develop lines that can be used for crossing purposes. From the research point of view inbreeding of value to determine the types of gene action that affect economic traits.
17. Genetic effects of inbreedingIt makes more pairs of gene in the population homozygous regardless of the kind of gene action involved. Effects of inbreeding
18. Genetic effects of inbreedingIt makes more pairs of gene in the population homozygous regardless of the kind of gene action involved. Effects of inbreeding
19. Effects of inbreedingPhenotypic effects of inbreeding a. Effect on growth rateb. Effect on reproductive performance: Prepotencyc. Effect on vigor: Consequence of inbreeding depressiond. Effect on production: Species of herd or block variatione. Appearance of abnormalities: Deleterious genes causing defects
20. Effects of inbreedingPhenotypic effects of inbreeding
21. Inbreeding can be divided into-InbreedingClose breedingLine breeding
22. Close breeding The mating of full sister to full brother or sire to his daughter or dam to her son. These types of mating should be only when both parents are outstanding individuals, and then only at the increased risk of bringing undesirable recessive genes into homozygous form in the progeny. Advantages Undesirable recessive genes may be discovered and eliminated by further testing in this line. The progeny are more uniform than out-bred progeny.
23. Close breeding The mating of full sister to full brother or sire to his daughter or dam to her son. These types of mating should be only when both parents are outstanding individuals, and then only at the increased risk of bringing undesirable recessive genes into homozygous form in the progeny. Advantages Undesirable recessive genes may be discovered and eliminated by further testing in this line. The progeny are more uniform than out-bred progeny.
24. Disadvantages The undesirable characteristics are intensified in the progeny if unfavorable gene segregation occurs.It has been observed that the progeny become more susceptible to diseases. Breeding problems and reproductive failure generally increase. It is difficult to find out the stage of breeding at which it should be discontinued in order to avoid the bad effects of the system.
25. Line breeding The mating of animals of wider degrees of relationship than those selected for close breeding. It promotes uniformity in the character. Homozygosity is not reached so quickly as in close breeding. Neither desirable nor harmful characters are developed so quickly. It is a slowed method for the fixation of hereditary outstanding bull or cow and the progeny is mentioned as being line-bred to certain ancestors.
26. ABCBDBEFig: Pedigree showing line breeding to B
27. Line breedingAdvantages 1. Increased uniformity.2. The dangers involved in close breeding can be reduced.Disadvantages The chief danger in line breeding is that the breeder will select the animal for pedigree giving no consideration to real individual merit. This may in some cases result in a few generations which receive no benefits from selection.
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