Abstract

    This study was undertaken to investigate the effects of age and season on the semen quality of 21 Sahiwal bulls kept under the similar managemental conditions at the Semen Production Unit, Qadirabad, District Sahiwal. These bulls were divided into 3 age groups i.e. group-I (upto 3 years), group-II (3-5 years) and group-III (above five years). Depending on the photo period  months of the year were grouped into 4 seasons i.e. Winter (November, December and January), Spring (February, March and April), Summer (May, June and July) and Autumn (August, September & October).
The results indicated that ejaculatory volume, motility percentage and doses produced by bulls of Group-II were significantly higher( P<0.05) than that of bulls of Group I and III. However mass activity, sperm concentration, pH and post thaw motility differed non significantly among bulls of three age groups. Generally all bulls showed better performance during Spring than other seasons of the year. It may be concluded that semen collected from mature bulls (adult bulls) during the Spring is of better quality than the semen of young and old bulls and also in Spring the quality of semen is better than the other seasons of the year.