Season Induced Changes in Seminal Characteristics of Sahiwal Breeding Bulls

The study was planned to determine the effect of seasonal variations on seminal characteristics of Sahiwal breeding bulls maintained at semen production unit, Qadirabad, district Sahiwal, Punjab, Pakistan. Semen ejaculates (N=1040) were collected weekly during the period of one year from Sahiwal bulls (N=10). Semen ejaculate volume was observed to be maximum with average 4.27±0.16 ml in winter which differed significantly p<0.05 with its lowest corresponding value in autumn (3.75±0.21 ml). Mass activity (expressed in scale 1-5) differed considerably p<0.05 throughout all seasons and was lowest (1.58±0.05) in humid summer but spring and dry summer yielded best values (1.99±0.05 and 2.00±0.06 respectively). Highest mean values of individual motility and sperm concentration (77.61±0.33% and 954.4±38.42 million/ml respectively) were also recorded in dry summer while lower mean values (75.96±0.91% and 845.7±34.70 million/ml respectively) were observed in autumn seasonIndividual motility in humid summer (74.91±0.65%) was significantly low (p≤0.05) as compared to all other seasons except autumn (77.61±0.33%). It is concluded that Sahiwal bulls produced better quality semen in spring and dry summer while humid summer and autumn were negatively impacting the semen quality.