Inbreeding and the gene pool.
The trend in the artificial insemination industry in recent years has been to sample larger numbers of sons sired by the most popular bulls. This trend has caused concern in the dairy industry regarding inbreeding and the gene pool. The known detrimental effects of inbreeding on economically important traits are one reason for this concern, and these are reviewed here. Also reviewed and discussed are estimates of inbreeding in dairy cattle populations. These estimates indicate that for the populations studied, inbreeding has increased little if at all during the period of widespread use of artificial insemination. During the 1970's average inbreeding in United States Holsteins and British Friesians was on the order of 3 to 6% relative to their foundations. A recent study of inbreeding in United States Ayrshires suggests little inbreeding in that breed in spite of the relatively small population size. Inbreeding and preservation of genetic variation should be minor concerns in selecting sires.
D000818:Animals; D002417:Cattle / Q000235:genetics*; D005260:Female; D005787:Gene Frequency; D005788:Gene Pool; D005828:Genetics, Population; D007178:Inbreeding; D007315:Insemination, Artificial / Q000662:veterinary; D008297:Male; D010375:Pedigree