Synchronization of estrus and ovulation in graz-ing cows with intramuscular injection of prosta-glandin F2α; in the case of administration of synthetic LH-releasing hormone, or human chori-onic gonadotropin followed

概要

論文の詳細を見る
Effects of changing the time interval from the injection of prostaglandin F2α (PGF2α) to the in-jection of synthetic LH-RH analog, [Des-Gly-NH102, Pro-ethylamide9]-LH-RH (LH-RH-I), or human chorionic gonadotropin (HCG) on synchronization of estrus and ovulation, and the fertility at synchro-nized estrus were investigated in grazing cows. A total of 86 cows (50 Holstein, 24 Japanese Shorthorn and 12 Japanese Black) in the functional luteal stage of the estrous cycle, weighing an average ±SD of 343±58 kg, were injected intramus-cularly (i.m.) with 10 mg of PGF2α. Out of them, 65 cows which showed regressive changes of corpora lutea during the period of 4272 hr after the treatment were assigned at random to three experi-mental groups; i.e. Group A (25 cows) received an i.m. injection of 200 μg of LH-RH-I, Group B (26 cows) received an i.m. injection of 1.000 i.u. or 2.000 i.u. of HCG and Group C (14 cows) received the PGF2α injection alone. Each of cows in both Groups A and B were divided into three treatment groups (I, II, III) due to the different time interval from the PGF2α injection to the injection of LH-RH-I or HCG; i.e. the time intervals for treatment I (Group A 8 cows, Group B 11 cows), II (8 cows, 7 cows) and III (9 cows, 8 cows) were 4247, 5760 and 7274 hr, respectively. The results obtained were as follows. 1) Percentage of the cows which showed standing estrus during the period of 3784 hr after the PGF2α injection in Groups A and B were 25.0% and 27.3% for treatment I, 37.5% and 42.8% for treatment II and 66.7% and 62.5% for treatment III, respectively, as compared to 71.5% in Group C. 2) All cows which did not exhibit estrus within 84 hr after the PGF2α injection in Groups A, B and C ovulated within 120 hr after the PGF2α treatment. 3) The average time interval ±SD from the PGF2α injection to ovulation in Groups A and B were 74.5±6.7 and 79.5±6.9 hr for treatment I, 88.0±3.7 and 87.0±4.6 hr for treatment II and 98.7±8.2 and 94.0±9.8 hr for treatment III, respectively, and that in Group C was 89.9±13.3 hr. 4) Conception rates by the insemination during 35 days post treatment in Groups A and B were 37.5% (3 of 8 cows) and 12.5% (1 of 8 cows) for treatment I, 37.5% (3 of 8 cows) and 42.9% (3 of 7 cows) for treatment II and 55.6% (5 of 9 cows) and 50.0% (4 of 8 cows) for treatment III, respectively, compared with 50.0% (7 of 14 cows) in Group C. These results indicate that the time of estrus and ovulation can be synchronized effectively using PGF2α in conjunction with synthetic LH-RH or HCG, and that the percentage of the cows which exhibit estrus, as well as the conception rate at the synchronized estrus, are increased as the time interval from the injection of PGF2α to that of ovulation-inducing hormone preparations are lengthened.
日本繁殖生物学会の論文

Synchronization of estrus and ovulation in graz-ing cows with intramuscular injection of prosta-glandin F<SUB>2α</SUB>; in the case of administration of synthetic LH-releasing hormone, or human chori-onic gonadotropin followed

スポンサーリンク

概要

日本繁殖生物学会 | 論文

スポンサーリンク