Sperm numbers, semen age and fertility in fresh and frozen bovine semen

The consequence of a seasonal mating pattern is that a significant amount of semen from the top sires is required during this intensive mating period to satisfy the demand. To utilise semen from these top sires efficiently, liquid semen technology has b een extensively used in New Zealand. This paper describes the essential physiological differences between liquid and frozen semen a nd their relative advantages and disadvantages. Alternative technologies such as freezing semen in bulk and later rediluted for us e as liquid semen can be used to overcome the constraints of an intensive mating season.