Spitzer JC, Carpenter RH. Estrus and pregnancy rates following synchronization with chronolone intravaginal sponge or norgestomet ear implant in cycling ewes.
Theriogenology 1981;
16:287-94. [PMID:
16725641 DOI:
10.1016/0093-691x(81)90013-3]
[Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/1981] [Accepted: 05/25/1981] [Indexed: 10/26/2022]
Abstract
Two experiments were conducted to evaluate the efficacy of a 3-mg ear implant of norgestomet, left in situ for 10 days, in conjunction with a single injection of 1.5 mg norgestomet and 0.5 mg estradiol valerate (EV) for controlling fertile estrus in the ewe. This treatment regime was compared with a 20-mg cronolone impregnated, intravaginal sponge left in situ for 14 days (Experiment 1) and a modification of the cronolone-sponge-treatment to include a single injection of 1.5 mg norgestomet and 0.5 mg EV (Experiment 2). The percentage of ewes synchronized was not significantly affected by progestin treatment (Experiment 1-cronolone pessary alone, 96%; norgestomet implant and injection of norgestomet and EV, 92%; Experiment 2-cronolone pessary + injection of norgestomet and EV, 84%; Norgestomet implant + injection of norgestomet and EV, 96%). In Experiment 1, the first service pregnancy rate (pregnant of ewes mated) of 80% for cronolone-treated ewes was significantly higher than the 59% observed in norgestomet-treated ewes (P<.05). In Experiment 2, no significant differences were observed in pregnancy rates between the two treatment groups (Cronolone, 57%; Norgestomet, 65%).
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