ANSC 313 Lecture Notes - Lecture 25: Standard Deviation, Heritability
LECTURE 8!
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Breeding Pyramid!
relates to breeding animals in an entire industry, for a particular species!•
breed and keep best (1)!•
send next best to multiplier!◦
nucleus !◦
breed more to distribute as breeding stock (2)!•
multiplier!◦
breed to sell for meat (3)!•
commercial!◦
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closed nucleus breeding scheme!
breeding stock only moves down between tiers!•
therefore the only genetic progress is in the nucleus!•
no gene flow into the nucleus ( monitor inbreeding levels)!•
used in poultry and win industries !•
WHY?!•
protects franchise rights of the members!◦
helps protect "high health " status!◦
nucleus:!•
closed selection!◦
multiplier:!•
increase numbers for sale of breeding gilts or boars!◦
typically closest multiplier gives the pigs!◦
several of them!◦
able to produce more breeding stock quickly!◦
commercial:!•
farrow to finish!◦
sell for meat!◦
don't clean out whole barn at once!◦
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Open nucleus breeding scheme!
best or superior animals from lower their can join herd in upper their!•
therefore the nucleus is not necessarily purebred!•
inbreeding in nucleus is reduced!•
response to selection 10-15%!•
PROBLEM: can not use if nucleus herd maintained as "disease free"!•
happens in cattle!•
nucleus : Elite purebred!•
using highest level of selection!◦
selling purebred stock to multipliers!◦
could buy heifers and take it back to there herd from the multiplier !◦
multiplier: average purebred ( sell bulls for crossbreeding)!•
getting at least bulls from the nucleus !◦
selling to commercial herds!◦
commercial: crossbreed calves produced for beef!•
not selling breeding stock only for meat!◦
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