Pedigree analysis of seven small French sheep populations and implications for the management of rare breeds

• Published in: Journal of animal science Vol. 88; no. 2; pp. 505 - 516
• Main Authors: Danchin-Burge, C, Palhière, I, François, D, Bibé, B, Leroy, G, Verrier, E
• Format: Journal Article
• Language: English
• Published: Champaign, IL American Society of Animal Science 01-02-2010; Am Soc Animal Sci
• Subjects: Agricultural sciences; ancestry; animal genetic resources; animal husbandry; Animal Husbandry - methods; animal production; Animal production studies; Animal productions; Animals; artificial insemination; Biological and medical sciences; Bleu du Maine (sheep breed); Breeding - methods; Charmoise (sheep breed); Cotentin (sheep breed); cryopreservation; farm management; Female; France; Fundamental and applied biological sciences. Psychology; Genes - genetics; genetic variation; Genetic Variation - genetics; germplasm conservation; inbred lines; Inbreeding; kinship; Life Sciences; Male; Pedigree; rare breeds; Romanov; Roussin de la Hague (sheep breed); semen; sheep; Sheep - genetics; sheep breeds; Solognote (sheep breed); spermatozoa; Terrestrial animal productions; Vertebrates; France; Population management; management of small populations; Farming animal; Genetic variability; pedigree analysis; Vertebrata; Meat animals; Mammalia; French; cryoconservation; Pedigree; Sheep; Artiodactyla; Ungulata; management of small population; sheep; genetic variability
• ISSN: 0021-8812; 1525-3163
• DOI: 10.2527/jas.2009-1961

Pedigree information was analyzed in 7 small populations of sheep raised in France (Bleu du Maine, Charmoise, Cotentin, on-farm Romanov, Romanov ex situ in vivo, Roussin de la Hague, Solognote) to estimate their genetic variability. The pedigree information for each breed, estimated by the number of equivalent generations traced, ranged from rather poor (4.6) to very good (10.5) when compared with other studies. On the basis of probabilities of gene origin, the effective number of ancestors ranged from 17 (on-farm Romanov breed) to 59 (Bleu du Maine). On the basis of the rate of inbreeding, the realized effective size was found to range from 65 (Romanov breed ex situ) to 231 (Bleu du Maine). The average kinship coefficients between rams from which semen doses are available in the French National Cryobank and the active ram and ewe populations were also computed. Results found in each breed were analyzed by taking into consideration the demographic evolution of the breeds, their management practices, and the use of cryopreservation as a way to preserve genetic variability. It appeared quite clear that, in populations in which AI with frozen semen is seldom used, factors that mainly affect the genetic variability are the female-to-male ratio, which should be as small as possible, and the number of reproducing female offspring by males, which should be as balanced as possible. Finally, our work showed that all populations under study have fairly good genetic variability in comparison with other species, despite their scarce numbers.