Role of Sex Chromatin on Performance in the Crossbred Cows

Abstract

This study was conducted on a total of 67crossbred cows in Erbil plain during the period from July/ 2014 to April / 2015, to study the role of sex chromatin shapes (Drum stick, Sessile nodule, Tear drop and Small club) on Daily Milk Yield (DMY), Lactation Period(LP), fertility rate and fertilize estrous sequences. We also study the effect of age of cows on the DMY, LP, and fertility and fertilize estrous sequences. The overall means of sex chromatin shapes drum stick, sessile nodule, tear drop shape and small club were 25.0 %, 35.0 %, 22.0 % and 18.0%, respectively. While the overall means of (DMY), LP, fertility rate and fertilize estrous sequences were 23.99kg, 197.46 days, and 87.13% and 1.54, respectively. The results showed that there is a significant (p≤0.05) different in relation to DMY, the highest rate of DMY showed among the cow, arise sex chromatin drum stick (28.86kg), lactation period (203.57), the small rate of DMY was low rate among the cows which arise sex chromatin tear drop and LP (192.63days). Significant effect of ages of cows on the patterns of sex chromatin had been observed. It was concluded from this study that the prediction of production milk production and reproduction (fertility rate and fertilize estrous sequences) performance of crossbred cows from shapes and percentage of sex chromatin distribution and measurements. The sex chromatin shapes in doing early selection the elite individuals on the linkage between sex chromatin shapes and performance production.

Keywords

• Crossbred cows, Sex chromatin, Milk yield, Repeatability and Correlation coefficient