Study on the Different Seasons and Climate Effects on Semen Quality in Breeding Bulls.

【Objective】The aim of this study was to analyze the effects of different seasonal climate conditions on semen qualities in bulls.【methods】Five bulls were randomly selected,and their semen liquids collected from July,January,April and September(representing the highest,lowest and moderate temperatures,respectively)were tested.【Results】The average of semen volume,sperm motility,sperm density,vitality rate of thawing of frozen semen,the production of frozen sperm number,and abnormal rate of these five bulls' semen collected in July(average temperature was 25℃)were 5.88 mL,67.2%,1.664billion/mL,33.8%,143.4doses,and 23%,respectively.In January,the average temperature was-11.2℃,and the average of semen volume,sperm motility,sperm density,vitality rate of thawing of frozen semen,the production of frozen sperm number,and abnormal rate of these five bulls' semen at this month were 5.7mL,66.8%,1.33billion/mL,37.4%,275.8doses,and 17.8%,respectively.In April and September,the average temperature was 12℃,and the average of semen volume,sperm motility,sperm density,vitality rate of thawing of frozen semen,the production of frozen sperm number,and abnormal rate of these five bulls' semen at these two months were 6.6mL,73.2%,1.692billion/mL,41.8%,404.4doses,and 12.6%,respectively.The semen volume,vitality rate and abnormal rate of semen collected at different seasons had significant differences(P0.05).But vitality rate of thawing of frozen semen and the production of frozen sperm number were not significantly different.【Conclusion】Suitable temperature(12℃~16℃)is very important for bulls to produce high quality semen.The ambient temperature is too high or too low will affect the quality of semen,and bull at the higher temperature will produce worse semen than under lower temperature.