Submitted to: Journal of Animal Science Supplement
Publication Type: Abstract Only
Publication Acceptance Date: July 24, 1995
Publication Date: N/A
Seventy-seven molecular markers were examined to determine whether any were involved in, or linked to, genes responsible for increased ovulation rate in a herd selected for twinning rate. Animals were evaluated for ovulation rate through 8-10 oestrous cycles, by rectal palpation of corpora lutea, and it is the average of these observations that was used as phenotypic information in the marker association study. A total of 90 offspring and 563 grand-offspring from 3 elite sires were chosen to be genotyped. Three significant markers, their estimate of effect (plus/minus SEM), probability value and the sire group in which they were significant were as follows: UWCA4 (-0.04 plus/minus 0.02; P = 0.06) within sire group 784403, UWCA20 (0.12 plus/minus 0.03; P = 0.0005) within sire group 839802 and CYP21 (- 0.046 plus/minus 0.017; P = 0.008) within sire group 839803. In order to analyze genotypes of the sons, an estimated breeding value for ovulation rate was used to replace average ovulation rate. Regardless of the analysis method used, each of the 3 markers described above remained significantly associated with ovulation rate. Markers flanking these significant markers are now being genotyped.