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| Question | Answer |
| animal breeding | the act of producing offspring (for the benefit of humans) |
| decisive factors in animal breeding | -breeding objectives -type of animal, its trait n its behavioral -methods to be used (normal vs technology) -breeding value |
| breeding strategies | 1. measurement effort n genetic evaluation 2. reproductive technologies existed 3. selection n mating |
| measurement effort n genetic evaluation | -to identify genetically superior animals -phenotypic measurementturned into estimated breeding value's (EBVs). fairly accurate -genotypic measurements 1. using molecular genetic technology 2. genes coding for factorial traits 3. genetic markers- improve estimation of animal's genetic potential 4. genetic variation- better assess of true genetic merit of animals |
| reproductive technolohy existed | -selection tools in animals breeding -increasing reproductive rate of genetically superior animals -example: cloning technique -sexual reproduction -in-vitro reproduction intraa-uterine insemination |
| selection n mating | PERMANENTLY MATED GROUPS females is allowed to litter in d presence of other members HAREMS females r placed w males n removed to separate cage prior to parturition HAND MATING female is placed w male only for brief period n then separated ARTIFICIAL INSEMINATION partners never meet |
| choosing a breeding pairs | 1. bright eyes 2. clear respiratory fx 3. healthy coat n skin 4. absence of parasites 5. good appetites 6. appropriate weight n size for age 7. good temperament 8. free from any disease |
| breeding program for rabbit | -similar to rodent -induced ovulator (doe will ovulate 10-12 hours after mating) -females mature at 3-4 months while buck matures at 4 months but they r often mate at 5-6 months of age -d doe is brought to d buck's cage n x d other way round -she is returned to her cage after confirmed visual mating -nesting box is provided early -doe pulls fur from her chest n stomach area to line d nesting box -gestation period is about 1 month -weaning age of kits 5-8 weeks -kit starts eating pellet at week 3 -breeding lifespan is 4-5 years |
| outbred stocks | -colonies in which each individual is genetically unique -will usually breed well under suboptimal conditions -suitable for many types of routine used- screening, teaching, toxological testing -in abundance in newly establish animal house -x suitable for advanced research such as immunology n cancer research |
| maintenance of outbreak stock | - kept d stock genetically constant -kept w no directional selection -low rate of inbreeding. w a raandom-mated colony, the rate of inbreeding per generation is i/generation = i/8m + i/8 f (i= rate of breeding) -recommended rate of inbreeding per generation should be less that 1%. higher inbreeding value means that d colony is too small to be maintain by random mating |
| inbred strains | -colonies in which all individuals r genetically identical -produced as a result of 20 or more consecutive generation of brother x sister mating |
| properties of inbred strains | - isogenicity -homozygocity -phenotic uniformity - long term stability -individuality -sensitivity -international distribution |
| isogenicity | genetically identical, organ transplantation without immunological rejection |
| homozygocity | homozygous at virtually all genetic loci. no genetic segregation among offspring. no hidden recessive genes |
| phenotypic uniformity | reflection of d genotype. fewer inbred animals r needed to achieve d same level of statistical precision |
| long term stability | genetically constant for long period of time. background data accumulated |
| individuality | each inbred strain is genetically unique n has own set of characteristics. so, each inbred strain is suitable for specific project |
| sensitivity | more sensitive to environmental influence n experimental treatments. fewer animals r needed in experiment |
| international distribution | research could be carried out in any countries using genetically identical animals |
| unique properties of inbred strains that not normally observed | normally recessive genes can be expressed useful in research to learn d fx of genes sometimes embryonically lethal genes r expressed |
| factors influencing breeding | -animal health -environmental conditions -canibalism n disertion |
| canibalism n disertion | -inexperienced females -overcrowding -poor environmental conditions -stress n disturbance |
| prevention of canibalism n desertion FOSTER MOTHER | -provided to young animals if the the natural mother has died, can't nurse or mother well, or is weakened during parturition - success is improved when offspring are close in age to that of the foster mother's own babies -some species r impossible to foster (hamster) - anticipate d need for a foster mother, so set up a coincidence mating from the foster colony |
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