Modification by propylene glycol of ovulation rate in ewes in response to a single injection of FSH.
Five experiments were conducted with the objective of developing a method to induce superovulation in ewes with a single i.m. injection of FSH. This was achieved by injection of 10 mg FSH-P in propylene glycol at the same time as luteolysis was induced by cloprostenol on day 13 of the oestrous cycle (day 0 = oestrus). Experiments 1, 2, 3 and 5 were conducted in a single flock of Manchega ewes in Spain during the breeding season. Ovulation rates were determined at laparoscopy. In Expt 1, FSH-P was diluted in saline, and neither 5 mg FSH on day 1 nor 5 or 10 mg FSH-P on day 13 changed the ovulation rate after cloprostenol treatment on day 13. In Expt 2, FSH-P was diluted in propylene glycol and data were collected over 2 years. Ten milligrams FSH-P, on day 13 only, increased (P < 0.01) the mean number of corpora lutea to 5.5 compared with a control value of 1.5. Five milligrams FSH-P on day 13 only had no effect; however, 5 mg FSH-P on day 1 reduced the mean number of corpora lutea formed in ewes receiving 10 mg FSH-P on day 13 to 2.6 (P < 0.01). Saline and propylene glycol, as vehicles for 10 mg FSH-P, were compared directly at two times of injection in Expt 3. FSH-P increased the mean number of corpora lutea when injected on day 13 in propylene glycol (4.7) but not in saline (2.5; P < 0.5).(ABSTRACT TRUNCATED AT 250 WORDS)
Lopez-Sebastian
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Departamento de Produccion Animal, Instituto Nacional de Investigaciones Agrarias, Centro de Investigación y Tecnología, Madrid, Spain.
Gomez-Brunet
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Lishman
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AW
Johnson
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Inskeep
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EK
D000818:Animals; D003008:Cloprostenol / Q000494:pharmacology; D004357:Drug Synergism; D005260:Female; D005640:Follicle Stimulating Hormone / Q000097:blood / Q000494:pharmacology*; D007273:Injections, Intramuscular; D007279:Injections, Subcutaneous; D010060:Ovulation / Q000187:drug effects*; D010062:Ovulation Induction / Q000379:methods*; D019946:Propylene Glycol; D011409:Propylene Glycols / Q000494:pharmacology*; D012756:Sheep; D013997:Time Factors
D011409:Propylene Glycols; D003008:Cloprostenol; D019946:Propylene Glycol; D005640:Follicle Stimulating Hormone