ANIMAL BREEDING Flashcards
art and science of the genetic improvement of farm animals
animal breeding
economically important traits in beef cattle (2)
- post weaning rate of gain
2. marbling score
economically important traits in dairy cattle (3)
- milk yield
- butter yield
- milk total solids
economically important traits in goat (3)
- multiple births (twinning)
- weaning weight
- milk yield
economically important traits in sheep (2)
- fleece weight
2. fiber diameter
economically important traits in horse (4)
- galloping speed
- trotting speed
- jumping style
- trotting pace length
economically important traits in chicken for meat (3)
- growth rate
- feed conversion ratio
- dressing percentage
economically important traits in chicken for eggs (4)
- egg production
- egg weight
- shell thickness
- haugh unit
economically important traits in ducks for eggs (4)
- egg production
- egg weight
- fertility
- yolk color
economically important traits in swine (4)
- ADG
- litter size
- loin eye area
- backfat thickness
may include selection, introduction of exotic animals (migration) and subsequent crossbreeding, induction of mutation and assortative and disassortative mating including inbreeding
SYSTEMS BREEDING
SYSTEMS BREEDING (3)
- selection
- inbreeding
- crossbreeding
process in w/c some individuals are chosen over others as parents of the next generation
- selection
measures the proportion of the total phenotypic variance that are attribute to the additive effects of genes that influence the given trait;
ranges from 0 - 1
heritability
*traits that are associated with reroduction (fertility and litter size) have LOWER heritabilities than those that are associated w/ physical conditions (body weight and back fat thickness)
suggests that all the phenotypic variation among individuals in the population is due to environmental and non-additive genetic effects
heritability value of 0
means that all the variability among individuals are only attributable to additive effect of genes
heritability of 1
heritability of the following characteristics of cattle:
amount of spotting
adult body weight
milk production
heritability:
- 9
- 6
- 3
heritability of the following characteristics of pigs:
percent of ham
litter size
heritability:
- 5
- 2
heritability of the following characteristics of chicken:
egg size
adult body weight
egg production
heritability:
- 7
- 4
- 2
form of non-random mating or a special case of assortative mating where individuals that are related by ancestry are mated together
- inbreeding
an offspring of a cross between two genetically unlike individuals
hybrid
reduction in fitness or vigor because of inbreeding or normally cross-pollinate organisms.
inbreeding depression
the mating between animals of different established breed;
results to large improvement in the average performance of the F1 progeny over that of the parents (called hybrid vigor or heterosis effect) in the presence of large dominance effects this.
- crossbreeding
involves the physical and physiological processes in both sexes leading to the fertilization of the egg by the sperm cell and the subsequent development of the young
animal reproduction
process of inducing fertilization in the female reproductive tract w/o the benefit of sexual contact between the male and female animal
artificial insemination (AI)
increase the rate of reproduction of the females that are selected to serve as an embryo donors to as much as 30 -50 times;
already been successfully demonstrated in cattle; not as widely practiced as AI
multiple ovulation and embryo transfer (MOET) technology
process by w/c the female animals is induced to simultaneously ovulate more eggs that what is normally shed
multiple ovulation
technique wherein a young embryo is collected from donor female parent and then implanted into the uterus of a recipient female parent
embryo transfer
