Systems of Mating Flashcards
alternative strategies for the mating of animals selected to be parents
systems of mating or mating systems
generally something to be avoided in animal breeding
inbreeding
what is inbreeding?
mating of related animals
True or false:
outbreeding increases the probability that more of the alleles at each gene in offspring or proogeny will be identical
false, inbreeding
the level of inbreeding is measured by what?
inbreeding coefficient
the inbreeding coefficient measures level of inbreeding
what is the inbreeding coefficient?
measure of the probability that alleles carried by that individual will be identical
consequences of increased inbreeding
- reductions in fertility
- reductions in litter size
- inbreeding depression (reduction in genera viability)
- increased incidence of genetic abnormalities
- loss of genetic variation (hence no genetic progress)
define line breeding
mating of animals in the same genetic line or selected groups which are not highly related
during the history of creating each breed, __________ is used; if used with care, can help estabilsh particular characteristics
clue: one of the reasons that pure breeds of livestock looks the same is due to a low level of inbreeding
line breeding
mating of animals in the same genetic line or selected groups which are not highly related
line breeding
mating of unrelated animals
outbreeding
define outbreeding
mating of unrelated animals
primary forms of outbreeding
- crossbreeding
- outcrossing
- linecrossing
- grading-up
- species hybridization
what does outbreeding take advantage of in livestock production?
heterosis and complementarity
aka hybrid vigor
heterosis
occurs when genetic merit (hence performance) of the cross[breeding] is greater than the average of parents
hybrid vigor / heterosis
commercial sows are often crossbreds of large white and landrace pigs because they exhibit _________ for all aspects of reproduction
bonus: if higher ______ for crossbred sows, then?
heterosis
bonus: higher heterosis for crossbred sows produce more litters with more piglets per liter
what are dam lines and terminal sire lines?
dam lines
- specialized female parents
- selected for a combination of goof female reproductive and growth performance
terminal sire lines
- specialized male parents
- selected for growth performance
what is breed complementarity?
using breeds as dam lines and other breeds as terminal sire lines
