4.Different Hereford, Angus and Holstein bull semen were used for in vitro fertilization of bovine oocytes, the purpose was to observe the effects of different bull semen on in vitro fertilization.

• 分别利用不同个体的海伏特、安格斯和荷斯坦种公牛精液进行体外受精；观察了不同品种不同个体种公牛精液的体外受精效果.