Effect of timing of frozen semen insemination on pregnancy rate in mares.
Thirty-four mares were inseminated with frozen semen from one stallion during 2 oestrous cycles, every 48 h until ovulation took place and within 12 h after ovulation. Semen was frozen using the Colorado method. The insemination dose was from 200 to 400 x 10(6) progressively motile spermatozoa. Ovaries were examined every 12 h to determine time of ovulation. Examination for pregnancy was carried out using ultrasonography, 15 days after ovulation. Thirty-five per cent of mares inseminated < 24 h and 23% of mares inseminated between 24-48 h before ovulation were pregnant (p = 0.388). The pregnancy rate in all mares inseminated before ovulation was 30%. In the mares inseminated within 12 h of ovulation, it was 18% (p = 0.253). Younger mares (aged 4-10 yr) had a higher pregnancy rate (59%) than older mares (aged 11-15 yr) (23%), but the difference was not statistically significant (p = 0.057).
Katila
T
T
Faculty of Veterinary Medicine, University of Helsinki, Saari, Finland. Terttn.Katila@Helsinki.Fi
Celebi
M
M
Koskinen
E
E
D000818:Animals; D015925:Cryopreservation / Q000662:veterinary*; D004971:Estrus; D005260:Female; D006736:Horses; D007315:Insemination, Artificial / Q000662:veterinary*; D008297:Male; D010060:Ovulation; D011247:Pregnancy; D011256:Pregnancy Outcome / Q000662:veterinary; D011270:Pregnancy, Animal; D012662:Semen Preservation / Q000662:veterinary*; D013081:Sperm Motility; D013997:Time Factors