ARTIFICIAL INSEMINATION IN SHEEP

Breeding through AI in sheep has of late assumed great importance. Commendable achievements have been made in the USSR, and Central and Eastern Europe. It has also given a good head-way in South America. The main objective of AI is to use the superior sire against a low performing female groups. In ewes the selection by phenotypical performance seems to be satisfactory till today. Further, compared to the prolific nature of breeding, flock-keeping and economics of AI do not seem to have an edge. In India AI in sheep was introduced in late 40's and early 50's. Much intensified work has not been done in ram semen. Visual estimates of the volume, density and colour are used to fairly estimate the concentration. There are 3 accepted methods of collection : (a) dry vagina of the ewes rams: are trained to serve non-oestrus ewes and the semen is then aspirated; (b) artificial vagina, (c) electro-ejaculation. Rams can ejaculate around 30 times in a day. Repeated collections made in a day for up to 16 times do not reveal any adverse situations. Further, seasons and nutrition regime have no detrimental effect on-fertility and serving ability. However, serious nutritional disturbances may tamper these.

Normally less than 1 million spermatozoa per ml dilution are not tolerated and inactivate the spermatozoa.Yolk-citrate-based extender with modifications are commonly used. Deep-freezing of ram spermatozoa and oestrus synchronization of ewes have been achieved and very much improved.The techniques of AI and the restraining of the female requires specific efforts. These techniques are designed to bring the eye of the inseminator at the level of the ewe's vagina. The importance of the technique is to see that semen is held in the cervix. Speculum is used to dilate and to have a clear view -of the cervix. Though AI in sheep and goat is not so much practised as in cattle and buffaloes, rapid strides"1: have been made in oestrus synchronization and embryo transfer (a method to propagate good genetic material through females.

(Source: Dr.Acharya, Handbook of Animal Husbandry)