Topic 38 Flashcards
Why is a breeding system needed?
To make sure that certain traits are transmitted from parents to offspring
Types of breeding methods
Purebred; Crossbreeding
Purebred
Inbreeding; line breeding; outbreeding; refreshments of blood
Crossbreeding
Breeding methods for breeding stock (continuous crossing); breeding methods for livestock (terminal crossing); hybridization
Purebreeding method
Mate animals in same breed, breeders can only use selection
Aims of purebreeding method?
Preserve breed, conservation of breed, commodity production, produce breeding animals for crossing
Inbreeding
Mate close relative animals, can find lethal recessive factors by inbreeding; inbreeding depression
Inbreeding depression
lower birth rates; reduced fertility; loss of immune system function
Line breeding
develops lines for certain aims, spread excellent sire improved effects for entire line
Outbreeding
crossing between different breeds
two unrelated individuals have been crossed to produce progenys; non relative breeding; recommended
Refreshment of blood
unrelated new male; same breed
Breeding methods for breeding stock
breeding and end product are the same
Types of breeding methods for breeding stock
genetic refreshment; breed improvement; grading up
Genetic refreshment
mating with another male of different breed
Breed improvement
using excellent sires from other breeds. R1 generation is bred with itself
Grading up
change entire breeding stock, 5-6 generation change
Crossbreeding for livestock
breeding and end product are different
Types of crossbreeding for livestock
Direct method; indirect method
Direct method
Whole F1 are end products.
Indirect method
Back crossing; crisscrossing
Backcrossing
crossbred female x ancestral breed
Crisscrossing
crossbred Femaile x purebred bull
Interspecies hybrid
Mule - female horse x male donkey; Liger - male lion x female tiger
