EFFECTS OF SITE OF INSEMINATION, SPERM MOTILITY AND GENITAL TRACT CONTRACTIONS ON TRANSPORT OF SPERMATOZOA IN THE EWE

Abstract

Summary. Three experiments were conducted to examine the effects of site of insemination, sperm motility and contractions of the genital tract on the transport of spermatozoa in the ewe. In the first experiment, the proportion of ewes from which spermatozoa were recovered from the Fallopian tubes was reduced, both in ewes receiving oxytocin (1 ·0 or 10·0 i.u., intramuscularly) and in those in which only shallow insemination could be achieved. The second experiment examined the effects of sperm motility (live versus dead spermatozoa), inhibition of genital tract contractions (halothane anaesthesia : −, + ) and stimulation of genital tract contractions (oxytocin injections: −, +). Sperm motility was found to be the most important factor affecting transport through the cervix. Oxytocin had little effect, but following insemination with immotile spermatozoa, inhibition of genital tract contractions reduced the number of spermatozoa recovered from both the cranial cervix and Fallopian tubes. The effects of site of insemination (external versus internal cervical os) and sperm motility (live versus dead spermatozoa) were examined in the third experiment. Few spermatozoa were found between the mucosal folds of the cervix when immotile spermatozoa were used. Large numbers of spermatozoa were recovered from both the cervix and Fallopian tubes after insemination at the level of the internal cervical os, particularly following the use of motile spermatozoa. The results demonstrate the importance of sperm motility, particularly in relation to the establishment of the cervical population of spermatozoa.