The effect of human chorionic gonadotropin on the development and function of bovine corpus luteum
2001
Nishigai, M. (Tokyo Univ. of Agriculture and Technology, Fuchu (Japan). Faculty of Agriculture) | Takamura, A. | Kamomae, H. | Tanaka, T. | Kaneda, Y.
Proceeding with research into human chorionic gonadotropin (hCG) administration, designed to promote pregnancy rates in embryo transfer, hCG was administered to bovine recipients on the day of ovulation in Holstein cows and the day of selection of recipients, ie. , day prior to embryo transfer (5 days after the day of ovulation) , and the changes in ovaries and the concentrations of plasma progesterone (P) and estradiol-17beta (E sub(2) ) levels after administration were determined. Changes in the ovaries and functions of blood P and E sub(2) levels after administration were determined in order to investigate the effects of hCG on increase in luteinization and functions of P secretion. Nine Holstein dairy cows were divided into two groups. All 4 cows of one group received an intramuscular injection of saline at a dose of 5 ml on the day of ovulation (Day 0-control group: the day of ovulation was designated as Day 0) , which was followed by an injection of hCG at a dose of 1,500 IU on the corresponding day of the next estrous cycle (Day 0-hCG group) . In a similar way, 4 cows in the other group received an injection of saline at a dose of 5ml on day 5 (Day 5-control group) , then 3 of the 4 cows and the remaining cow received intramuscular injections of hCG at a dose of 1, 500 IU on the corresponding day of the next estrous cycle (Day 5-hCG group) . These cattle were examined for changes in ovarian follicles and corpus luteum (CL) every day or every other day by rectal palpation and ultrasonography, and blood samples were collected every day for the P and E sub(2) analysis.
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