DefinePK

Abstract

Bulls and climatic changes at the time of mating may influence offspring sex ratio. This survey was justified to judge the effect of year and month of mating as indicator to climatic temperature change on sex ratio of buffalo calves. Records from 413 buffalo bulls and their 1672 calves produced after mating from year 2000 to 2015 were collected. The data were analyzed for the effect of year and month of mating on the sex ratio using Chi-square test. The results showed that 15.01% of bulls had only female calves, 19.37%have only male calves and 65.62% of bulls have both male and female calves. The number of calves born using natural mating were 1672 from which 909 (54.4%) were males and 763 (45.6%) were females. The overall ratio (male/female) in all recorded years was 54: 46. It did not show a statistical variation for the effect of the year of mating. However, for the effect of mating month, there was a significant (P<0.01) increase in male calves during January, March, April, June, July, August and October. In conclusion, the total sex ratio did not show a statistical variation during 15 years. But increasing in male calves during the warm months and the coldest month of the year could be related to the resistance of male embryos to the adverse effect of climatic change in Egypt. This information is basic for buffalo breeder to take the effect of mating month in their consideration.