Oxytocin-induced cervical dilation in sheep: mechanism of action and potential use for nonsurgical artificial insemination

Exogenous oxytocin aids in the transcervical passage of an AI pipette into the uterus of ewes, and it may be an effective adjunct to sheep AI procedures. Experiments were conducted to evaluate the effects of oxytocin on variables that may affect fertility. The results of this study indicate clearly that oxytocin dilates the cervix in ewes (Exp. 1) without affecting the movement of sperm to the oviducts (Exp. 3) or fertilization rate (Exp. 9). Oxytocin probably binds to uterine and cervical receptors (Exp. 6) and stimulates uterine tetany (Exp. 2) and prostaglandin release (Exp. 5). Because of the irregular arrangement of smooth muscle in the sheep cervix (Exp. 4), uterine tetany may physically dilate the cervix. Also, prostaglandin synthesis, primarily PGF2, may be involved in a chemical softening of the cervix. Most likely, a combination of uterine contractions and cervical softening allow dilation and transcervical passage of an AI pipette. Although oxytocin does not affect sperm transport (Exp. 3) or fertilization (Exp. 9), fertility after transcervical AI is decreased (Exp. 8). Cervical manipulation seems to decrease fertility, but the mechanism is unclear. Therefore, a greater understanding of the physiology of the sheep cervix is necessary before oxytocin-induced cervical dilation can be implemented with nonsurgical AI procedures in sheep.

Name thesis:degree_name

Ph. D.

Level thesis:degree_level

doctoral

Discipline thesis:degree_discipline

Animal Science (Physiology of Reproduction)

Department dc:contributor.department

Animal Science (Physiology of Reproduction)

Grantor dc:publisher

Virginia Tech

Year dc:date.issued

1995

Author dc:creator

• Sayre, Brian L.

Chair dc:contributor.committeechair

• Lewis, Gregory S.S.

Committee members dc:contributor.committeemember

• Knight, James W.
• Saacke, Richard G.
• Akers, Robert Michael
• Umberger, Steven H.

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Language dc:language.iso

en

Dc Identifier Other

etd-10262005-143554

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/40251