Study of the pregnancy efficiency (conception rate) according the seasons and months in the Arab mares

In order to understanding the reproductive performance of Arab mares in Dezful city under natural photoperiod and selecting the appropriate month for the conception, statistical data related to reproductive characteristics)Number of tractioned animals and the number of pregnancies in this regard(of healthy mares 3 to 18 years were collected from April 1998 to the May 2012. Data was analyzed by using Excel program and after calculating the efficiency of pregnancies in the each seasons and months, results analyzed in a completely randomized design using SAS software and comparison of means was performed by using Duncan's test. The results show that between the months of spring, summer and winter, the pregnancy efficiency Percent under natural photoperiod was significant (P<0/05) but not between autumn months (P>0/05). Also the result showed that highest reproductive activity and pregnancy efficiency Percent was in April May, June and March, respectively and lowest reproductive activity and pregnancy efficiency Percent was in December, November, October and January, respectively. According to these results, the autumn is anestrous season and spring is the best reproductive activity season in the mares of this area.