Elucidation of Mechanisms of temperature gradients in female reproductive tracts under heat-stressed condition and improvement of reproductive performance in cattle

2023 Fiscal Year Final Research Report

• Project/Area Number: 20K15647
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 42010:Animal production science-related
• Research Institution: Obihiro University of Agriculture and Veterinary Medicine (2021-2023); Nagoya University (2020)
• Principal Investigator: Morita Yasuhiro 帯広畜産大学, 畜産学部, 准教授 (90818262)
• Project Period (FY): 2020-04-01 – 2024-03-31
• Keywords: 卵巣 / 暑熱環境 / 血流 / 繁殖管理

Outline of Final Research Achievements

This study aims to determine whether the disruption of the temperature gradient around the female reproductive tract is the cause of ovarian dysfunction under heat conditions. We indicated that ovulation failure under heat-stressed conditions in Japanese Black cattle could be due to suppressing follicle formation in the ovary. We also demonstrated that body temperature usually increases during estrus, but eye temperature significantly decreases from estrus to ovulation in Japanese Black cows. In addition, we revealed that differences in milk fat contents in dairy samples raised in Cambodia under heat-stressed conditions were related to differences in genetic character. Through these studies, we have accumulated basic knowledge to prevent ovarian dysfunction in heat conditions by modulating the temperature gradient in the reproductive tracts.

Free Research Field

動物生産科学

Academic Significance and Societal Importance of the Research Achievements

本研究では、黒毛和種牛においては暑熱条件下での排卵不全は、卵巣における卵胞形成の抑制が原因である可能性を示した。この結果からは、視床下部や下垂体だけでなく、卵巣に焦点を当てた管理を提言でき、暑熱環境下での繁殖管理に新たな視点を提供できる。また、眼球温を観察することで発情から排卵の時期の推定ができることを示した結果は、新たな非接触での発情観察技術の開発につながる。加えて、カンボジアの在来牛が保有する暑熱耐性の遺伝的特徴を明らかにした結果は、暑熱環境下での在来牛を使用した育種へ利用できる。本研究で得られた結果は、今後の気候変動に対応し、持続可能な畜産体系の確立に貢献すると考えらえる。