TRANSCERVICAL INSEMINATION IN SHEEP - AN ANATOMICAL AND HISTOLOGICAL-EVALUATION

The use of transcervical artificial insemination (TC AI) of sheep has been under investigation since its development at Guelph, Canada in 19 90. The TC Al method may provide an insemination technique which has a lower ethical cost than current laproscopic techniques which requires minor surgery. This trial evaluated the anatomical location of the in semination needle and the histological effect on the reproductive trac t of ewes using TC AI. Two groups of ewes were inseminated using, firs tly, an unmodified AI needle (UN; n = 20) and then a second group (n = 10) was inseminated using a modified needle (MN). All ewes were eutha nased and histological examination was undertaken on the cervix. In th e first group there was indication that the UN passed out of the repro ductive tract through the cervical wall in 31.6% of inseminations. Aft er modification of the needle this was reduced to 10%. A high degree o f accuracy (79% and 92%; UN and MN needle respectively; P < 0.01) was observed for the operator to predict location of the AI needle. Histol ogical examination revealed damage to the epithelial lining of the cer vix at all points of examination in ewes in which penetration reached the uterus and this group, along with the group in which penetration s topped in mid-cervix, had more damage (P < 0.01) than the group in whi ch the needle left the tract. In summary varying degrees of damage occ urs to the cervical lining over the length of the cervix that the TC A I needle penetrated and therefore there is some ethical cost to the an imal by use of the technique.