Results of insemination of mares with fresh and frozen stallion semen.

Artificial insemination using deep-frozen semen was performed on 116 mares in 1973 using twelve ejaculates from eight stallions of the Hanoverian breed. Despite the fact that the quality of the semen used was poor, the majority of the mares inseminated were subfertile and some mares were inseminated during one oestrus only, 44% nevertheless conceived and gave birth to live foals. Of a small group of ten mares inseminated in the same year with fresh semen, seven conceived.