| 研究課題/領域番号 |
15K18769
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| 研究機関 | 名古屋大学 |
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研究代表者 |
PHENG Vutha 名古屋大学, アジアサテライトキャンパス学院(農), 特任准教授 (70747120)
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| 研究期間 (年度) |
2015-04-01 – 2018-03-31
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| キーワード | Heat stress / Tropical climate / HRV / dairy cattle |
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| 研究実績の概要 |
Crossbred local zebu and Holstein cows were adapted at the diary research farm at Nagoya University satellite campus at RUA and were used for the research on heat stress under the tropical climate. The purposes of the study are to understand behavior and the physiological responses to heat stress under the sunlight condition via applying the electrocardiogram to measure the activities of autonomic nervous system including sympathetic and parasympathetic system and specifically the heart rate variabilities (HRV).
Approximately, one third of the project has been done and the data analysis also reveals results of the project. The results clearly show that when the cows were kept under the sunlight the activities of sympathetic nervous system increases while the HRV significantly decreased and rectal temperature was higher than when they were kept inside the shelter. The study demonstrates that the dairy cows in Cambodia perceive stress under direct sunlight. Additional data are being collected and to be merged with the current existing data for analysis as the same group of dairy cattle.
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| 現在までの達成度 (区分) |
現在までの達成度 (区分)
3: やや遅れている
理由
As the research on heat stress on dairy is conducted in Cambodia where the tropical summer heat generally falls between March to early June, the fluctuation of the climate changes in 2017 from March to April, in which the weather has been cool and rain, causes the delay of the experiment. Because such weather will contribute to error of data retrieval. Then the experiment is awaiting for the return of the summer heat so that the measurement of heat stress on Cambodia dairy cows can resume. It is likely that it can resume at the fourth week of April 2017 to complete collecting all the data for the whole project.
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| 今後の研究の推進方策 |
The next plan is to compare the levels of stress responses between local cows zebu and those crossbred with Holstein gene. The experiment will follow similar protocol use earlier on diary cows by adding the local cows as control group in order to understand the heat tolerance and heat stress of both cows with different genetic background.
Another plan is to understand the negative effects of heat stress on reproduction in dairy cattle. Because it has been well known that hot climate affect negatively on the health and performance of dairy cattle. Thus it would also affect the reproductive function which the critical issues in dairy production.
The other plan is to measure the growth performance of local cattle zebu with different types of feeds under proper management.
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| 次年度使用額が生じた理由 |
Due to the delay of experiment last year to get enough data, the experiment is going on from April 2017 and will continue to get additional data to complete the project by the end of March 2018. Thus it is necessary to use the fund to support the experimental work for this research project.
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| 次年度使用額の使用計画 |
The fund will be used for purchasing necessary items to support the experiment work at the farm and purchase feeds for the cattle.
Some of the fund will be used for traveling for attending and presenting work at conferences and for meeting to discuss on research work with research team in Japan.
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