Breeding Pyramids Flashcards
what is a breeding pyramid (draw it)
nucleus(breed selected replacements), multiplier (males and females bred for sale), commercial(males and females raised for product)
what is the only genetic progress?
the nucleus
what is a closed nucleus breeding scheme?
gene flow only downwards
no genes flow into nucleus
why use a closed nucleas breeding scheme?
poultry - to protect franchise rights on crosses
swine - to maintain disease status
what is improvement lag
difference in performance between any 2 adjacent tiers (expressed in number of years)
what can affect the size of improvement lag?
age structure in lower tiers
source and quality od sires and dams in lower tiers
what can shorten improvement lag?
keeping stock in lower tiers
transfer both males and females downwards
what is an open nucleus breeding scheme?
best or superior animals from lower tier can join herd in upper tier
therefore, the nucleus is not necessarily purebred
inbreeding in nucleus is reduced - 50%
response to selection increase 10-15%
what is a problem with open nucleus breeding schemes
can not use if nucleus herd is maintained as disease free
what is a herd book
registry documentation for breed - created by breed associations
what are closed breeds
british breeds - angus and hereford (milking)
what are open breeds
continental or exotic - charolais, simmental, limousin, salers, maine Anjou
what is the animal pedigree act?
canadian fedral law pertaining to purebred animals
gives much authority to breed associations
canadian breed associations send proof of purebred/pedigree within 6 months
who is required to have livestock records?
smaller beef breeds - belgian blue, galloway and others
most horses - except thoroughbreds - jockey club
sine sheep goat bison donkey and mules
