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.