Genet. Sel. Evol.
Volume 40, Number 4, July-August 2008
|Page(s)||415 - 432|
|Published online||17 June 2008|
Sustainable long-term conservation of rare cattle breeds using rotational AI siresJean-Jacques Colleau1 and Laurent Avon2
1 INRA, UR337 Station de génétique quantitative et appliquée, 78352 Jouy-en-Josas Cedex, France
2 Institut de l'élevage, Département Génétique, 149 Rue de Bercy, 75595 Paris Cedex 12, France
Received 21 September 2007; accepted 30 January 2008; published online 17 June 2008
Abstract - The development of inbreeding in rotation breeding schemes, sequentially using artificial insemination (AI) sires over generations, was investigated for a full AI scheme. Asymptotic prediction formulae of inbreeding coefficients were established when the first rotation list of AI sires (possibly related) was in use. Simulated annealing provided the optimal rotation order of sires within this list, when the sires were related. These methods were also used for subsequent rotation lists, needed by the exhaustion of semen stores for the first bulls. Simulation was carried out starting with groups of independent sires, with different sizes. To generate a yearly inbreeding rate substantially lower than 0.05% (considered to be within reach by conventional conservation schemes using frequent replacements), the results obtained showed that the number of sires should be at least 10-15 and that the same sires should be used during at least 50 years. The ultimate objective was to examine the relevance of implementing rotation in breeding schemes on the actual rare French cattle breeds under conservation. The best candidate for such a test was the Villard-de-Lans breed (27 bulls and 73 000 doses for only 340 females) and it turned out to be the best performer with an inbreeding coefficient of only 7.4% after 500 years and five different sire lists. Due to the strong requirements on semen stores and on the stability of population size, actual implementation of this kind of conservation scheme was recommended only in special (`niche') cattle populations.
Key words: conservation / rotation / inbreeding / coancestry / artificial insemination
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© INRA, EDP Sciences 2008