Date of Award:

1994

Document Type:

Thesis

Degree Name:

Master of Science (MS)

Department:

Wildland Resources

Advisor/Chair:

Thomas D. Bunch

Abstract

The only practical method for artificially breeding ewes with frozen semen is laparoscopic insemination into the lumen of the uterine horn. Like all surgical procedures, however, laparoscopic artificial inseminatiom has limitations. The procedure requires surgical skill and costly equipment. Repeated passage of the laparoscope through the abdominal wall causes adhesions. Depositing frozen/thawed semen at the os cervix results in low conception rates. The inability to pass an insemination pipette through the cervix has prevented artificial insemination in sheep from becoming a standard breeding method as in the cattle industry. This study compared laparoscopic and transcervical methods of insemination in nulliparous ewes and transcervical insemination in multiparous ewes after estradiol cypionate treatment.

Forty nulliparous commercial-cross Rambouillet ewes were treated with pessaries containing fluorogesterone acetate to synchronize estrus. After 14 days, pessaries were removed and ewes were injected IM with 400 IU of pregnant mare serum gonadotropin (PMSG). Ewes were randomly divided into laparoscopic and transcervical treatment groups, 14 and 26 respectively. Ewes were inseminated with thawed semen (75x106 motile spermatozoa). Pregnancy rate with laparoscopic insemination was 85% (confirmed at 55 days with real-time ultrasound) .. With the transcervical method, the speculum could only be inserted into the vagina of five ewes and the insemination pipette could only be passed through the cervix in two ewes. The combined pregnancy rate for deep cervical and transcervical insemination was 40% at 55 days.

Forty multiparous commercial-cross Rambouillet ewes were synchronized as previously described. Ewes were randomly separated into a control and estradiol cypionate treatment group of 20 animals each. Within each group 10 ewes were inseminated with frozen/thawed Suffolk semen and 1 Owith Rambouillet semen. Ten ewes within each sire genotype were treated with 1 mg IM of estradiol cypionate 16 hours prior to insemination. Treated ewes were inseminated into the uterine body 90% of the time and non-treated ewes 95%. There was no significant difference in cervical passage between these groups.

Pregnancy rates for transcervical artificial insemination in the Suffolk genotype were 0.05% and 40% in the Rambouillet (pregnancy confirmed at 55 days by real-time ultrasound). Lambing rates for the Suffolk and Rambouillet groups were zero and 0.05%, respectively.

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