Breeding and Genetics II.

This article presents abstracts of various papers related to the breeding and genetics of animals, that were presented during the symposium held on July 26, 2005, Cincinnati, Ohio, which was organized by the American Dairy Science Association, the American Society of Animal Science and the Canadian Society of Animal Science. One of the papers presented is "Fine Mapping of a Bovine Twinning Rate QTL," by E.S. Kim. A twinning rate quantitative trait locus (QTL) has been previously detected on chromosome 5 in the North American Holstein dairy cattle population. The objective of the current study was to refine the map location of this QTL. In the previous work the strongest evidence for this QTL was obtained from analysis of an extended, four-generation sire family. Another paper discussed is "X- and Y-Cromosomes Bearing Sperm Ratio in Individual Bull Ejaculation," by J. Schenk, M. Meyers and E. Crichton. Small sample sizes often lead to erroneous conclusions about true sex ratios due to binomial statistical variation. DNA resort reanalysis, PCR and fluorescence in situ hybridization can be used to accurately determine sex ratios in a sample of semen.