Equine reproduction: advances in artificial insemination techniques

This article covers recent developments in the field of equine artificial insemination. Use of both chilled and frozen semen is discussed. For chilled semen, there is new information about what to do if the semen shipment is delayed and on maximising pregnancy rates in older mares by careful evaluation of the cervix. The number of motile sperm needed for insemination is reviewed in light of the finding that very few sperm actually reach the site of fertilisation. A new technique to improve semen quality using special filters is reported. For frozen semen, the technique of deep uterine insemination is discussed in detail. In this technique, sperm is placed at the tip of the uterine horn rather than in the uterine body. The two different methods – using a rectally-guided catheter and using a videoendoscope – are compared. Pregnancy rates using the two different techniques were found to be similar and pregnancies could be achieved with inseminating sperm numbers as low as 50 million.