1986 Fiscal Year Final Research Report Summary
Studies on the reproductive endocrine system in long-term infertile dairy cows
| Project/Area Number |
59440018
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| Research Category |
Grant-in-Aid for General Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Research Field |
Applied veterinary science
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| Research Institution | Tokyo University of Agriculture and Technology |
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Principal Investigator |
HOSHINO Kunio Tokyo University of Agriculture and Technology, Professor, 農学部, 教授 (40157011)
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| Co-Investigator(Kenkyū-buntansha) |
TAYA Kazuyoshi Tokyo University of Agriculture and Technology, 農学部, 助教授 (60092491)
笹本 修司 東京農工大学, 農学部, 教授 (20014946)
MORI Yuji Tokyo University of Agriculture and Technology, 農学部, 助手 (40157871)
SASAMOTO Shuji Tokyo University of Agriculture and Technology
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| Project Period (FY) |
1984 – 1986
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| Keywords | Veterinary Reproduction / Cow / Female Infertility / Gonadotropin / Sex Steroid / Diagnosis / Treatment / 直腸検査 |
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| Research Abstract |
Infertility in the cow, particularly the long-term infertility, is the major hindrance of the dairy management. The present study was conducted to assess the reproductive endocrine function in the long-term infertile cows. Following results were obtained.
1. Disposal rate was considerably high in the long-term infertile cows, although no distinguishable change was found in peripheral levels of reproductive hormones and the main reasons for disposal were the obesity and the diseases other than infertility. It is therefore recommended to diagnose the cows which have reproductive problems as early as possible and adequately treat them before they fall into an annoying state of long-term infertility.
2. Reproductive endocrine conditions and clinical signs were compared among various types of infertile cows. Plasma progesterone was significantly higher after day 9 (day 0: insemination) and the estradiol/progesterone ratio was lower between day 6 and day 9 in successively conceived cows as com
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pared with those failed to do so. Hormonal treatments on day 5 or 6 were found to greatly improve conception rate of the cows being found abnormalities at the insemination. These results suggest that normal development of luteal function accompanying sufficient progesterone secretion is essential for the survival of early embryos.
Concentrations of estradiol and progesterone were assayed in the fluid of follicular cyst (FC), luteal cyst (LC), large follicle accompanying corpus luteum (CL) or cystic corpus luteum (CCL) as well as in the matched peripheral blood samples. Estradiol and progesterone concentrations in the ovarian fluids showed great variance extending from pg/ml to ng/ml levels. The ovarian cysts were endocrinologically classified into 6 types of FC and LC, and it was confirmed that FCL and CCL are completely different from LC and FC. From the results of present study we could summarize the methods for the diagnosis and treatment of infertile cows on the endocrinological basis. Less
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