Effect of oxytocin treatment during oestrus on the ovulation rate of Merino ewes.
The effect of oxytocin treatment on the ovulation rate of Merino ewes was investigated. Intravenous doses (0.1 IU) of oxytocin were administered to synchronised ewes (n = 54) every 30 min for a 24 h period beginning at the onset of oestrus. Laparoscopic examination of the ovaries of all ewes that had displayed overt oestrus following sponge withdrawal was performed 10 d after the beginning of oxytocin treatment to determine the number of corpora lutea per ewe. The ovulation rates of the treated and control groups were 174.5% and 144%, respectively (p < 0.01). It would appear that a higher ovulation rate can be obtained by repeated low-dose intravenous injection of oxytocin during oestrus.
King
P R
PR
Grootfontein Agricultural Development Institute, Middelburg, South Africa.
Coetzer
W A
WA
D000818:Animals; D004971:Estrus / Q000187:drug effects*; D005260:Female; D010060:Ovulation / Q000187:drug effects*; D010121:Oxytocin / Q000494:pharmacology*; D012756:Sheep / Q000502:physiology*
D010121:Oxytocin