抄録
Twenty-eight cows with cystic ovarian disease (COD) were used. In them oneor more follicular cysts 2.0 cm or more in diameter persisted for at least l to 2 weeks. Theyexhibited such abnormalities either in estrous signs as masculinized appearance, intensiveestrus, continuous estrus, feeble estrus, and anestrus or in the estrous cycle as ata irregularcycle or a lack of cycle. Of the 28 cows, six were derived from herds which had often beentreated with a large dose of gonadotropin for COD (Group A) and the remaining 22 cowsfrom herds rarely treated with gonadotropin (Group B). The 6 cows of group A wereinjected intramuscularly (i.m.) with 2, 000 pg of gonadotropin-releasing hormone (GnRH).Of the 22 cows of group B, ten were injected i.m. with 1, 500 pg, three i.m. with 2, 000 pg, seven intravenously (i.v.) with 1, 000 pg, and two i.v. with 3, 000 pg of GnRH. Blood sampies were collected from 21 cows via the jugular vein before the treatment and from 5 cowsagain 6 to 9 days after the treatment.Sixteen (57%) of the 28 cows conceived after the GnRlI treatment. There was a signifi-cant difference (P i0.05) in recovery rate (the number of cows which conceived / the num-ber of cows treated) between the two treatment groups. No cows of group A respondedto GnRII, but 16 COXVS of group B showed response to GnRH. There seems to be littledifference in effects of GnRH among the cows given different doses either intramuscularlyor intravenously.There was a trend that the pretreatment serum level of progesterone was higher in thecows having responded to GnRH than in those not responding. In 4 cows with fo1[icu]arcysts luteinized, the serum level of progesterone increased remarkably 6 to 9 days after theinjection, but did not in 1 cow with follicular cysts remaining unchanged.
