Relationship between reproductive performance and thermal gradient in reprodoctive organs

2019 Fiscal Year Final Research Report

• Project/Area Number: 19K21167
• Project/Area Number (Other): 18H06030 (2018)
• Research Category: Grant-in-Aid for Research Activity Start-up
• Allocation Type: Multi-year Fund (2019); Single-year Grants (2018)
• Review Section: 0605:Veterinary medical science, animal science, and related fields
• Research Institution: Nagoya University
• Principal Investigator: Morita Yasuhiro 名古屋大学, アジアサテライトキャンパス学院(農), 特任助教 (90818262)
• Project Period (FY): 2018-08-24 – 2020-03-31
• Keywords: 暑熱 / 卵巣 / 子宮 / 心拍変動解析 / ストレス評価

Outline of Final Research Achievements

Reproductive performance of livestock animals is very important in calf production, which is one of the major critical factors affecting farmers’ income. Generally, heat stress suppresses reproductive performance in cattle. The understanding of physiological response related to heat stress is essential for improving reproductive performance. Therefore, in this study, I tried to establish appropriate methods for observing the response of reproductive organs and sympathetic response to heat stress. As a result, I established new recording method for reproductive organ temperature continuously, thereby I elucidated that reproductive organs have temperature gradients and this gradient is maintained during estrus period. I also develop an analysis of the heart rate variability (HRV) and indicated that HRV analysis is useful methods for evaluating cow response to heat stress.

Free Research Field

家畜繁殖学

Academic Significance and Societal Importance of the Research Achievements

本研究によって確立した観察方法、ストレス評価法によって、性周期のどの時期に雌生殖器周囲の温度勾配が保たれることが卵胞発育および排卵において重要であるか、どの程度のストレスでこの維持機構に変化が起きるか解明することが可能である。これによって、暑熱期における牛群の管理方法に新たな知見を加えることが可能となり、日本のみならず、放牧主体で飼養せざるを得ない、熱帯地域の発展途上国での酪農または肉用牛生産においては重要な知見に繋かがると考えられる。また、同一条件下でも温度勾配が維持されている耐性個体を選抜することで、熱帯地域に根ざした育種の可能性も考えられる。