Fresh and Post Thaw Quality Characteristics of Holstein Friesian Bull Semen

The study was conducted to determine the quality characteristics of fresh and post-thaw semen of Holstein Friesian bull. The cow bulls were maintained at Semen Production Unit, Quetta Baluchistan. The semen ejaculates were evaluated for volume, pH, mass activity, sperm concentration, sperm motility and sperm cell membrane integrity. The semen qualifying these criteria were processed for freezing. The frozen semen after thawing was assessed for progressive linear motility and percentage of intact cell membrane.  The mean ejaculate volume of collected semen was recorded as 6.93, 6.59 and 6.61 ml, pH; 6.58, 6.59 and 6.61, mass activity of sperms 3.87, 3.75 and 3.5 and sperm concentration 1349.12x106, 1509.37x106  and 1364.37x106 /ml during the month of May, June and July respectively.  The color of semen was not consistent pattern, it varied as creamy white and milky white. The motility of fresh and post thaw semen was assessed as 73.9 vs 48.75%; 75 vs. 53.75%; 75 vs. 53.12% for the month of May, June and July respectively.  The membrane integrity of the fresh semen samples over a period of three month was 58.37% against post-thaw membrane integrity of 44.79%. It was concluded that the objective method of Osmotic Resistance Test was found to be useful parameter for assessment of in-vitro quality of the semen. The semen of Holstein Friesian bull tolerates freezing and thawing stress and maintained reasonable good fertility. The summer season has no significant adverse effect on quality of semen and thus the semen collected could be considered for artificial insemination program.