B. J. Isler*, K. M. Irvin*1, S. M. Neal‡, S. J. Moeller*, M. E. Davis*,
and D. L. Meeker*
*The Ohio State University Department of Animal Sciences
‡The Ohio State University Agricultural Technical Institute
The identification of genes or markers associated with reproductive traits in swine is an important area of research, due to the large economic impact that these discoveries could have on the swine industry. It has previously been reported that one of these genes, the estrogen receptor (ESR) gene, is associated with increased litter size in pigs. There has been little research, however, on the association between the ESR gene and other litter traits, such as number of piglets alive at weaning. The purpose of this study was to investigate the association between ESR genotype and these litter traits in a population of 322 Large White, Yorkshire, and crossbred pigs. Two hundred twelve litter records from these animals were collected and analyzed for associations between ESR genotype and the following litter traits – number born, number born alive, litter weight of animals born, litter weight of animals born alive, number of mummies, number of stillborn animals, number of overlaid animals, number of animals at weaning, and litter weight at weaning. Data were analyzed using a model that included the effects of ESR genotype of dam, parity, farrowing month, dam breed, sire breed, and significant two-way interactions. Some litter traits displayed favorable, but not statistically significant, trends with respect to ESR genotype – litter weight born alive, litter weight born, number of stillborn pigs, number of pigs at weaning, and total litter weight at weaning. Paternal and maternal breed effects were also found for several of the litter traits studied. Dams with Large White fathers had an increased number of stillborn piglets (P = 0.08) and an increased number of mummies (P = 0.07). Dams with Large White mothers had an increased number of piglets alive at weaning (P = 0.10) and an increased litter weight of piglets alive at weaning (P = 0.001).
1 For more information, contact at: The Ohio State University, 110F Animal Science Building, 2029 Fyffe Road, Columbus, OH 43210, 614-292-6407, Fax 614-292-2929, e-mail: irvin.3@osu.edu