Effect of environmental thermal stress on reproductive performance of Holstein cows in Egypt

Abstract

ABSTRACTThe aim was to investigate effects of ambient temperature-humidity index (THI) on the reproductive indices of 920 Holstein (HO) cows in the subtropics. THI was categorized as low: below 70; moderate: from 70 to 75 and high: more than 75. The high THI significantly (P < 0.001) prolonged the periods of calving interval, days open and dry period, and increased the service per conception rate. The conception rate in the high THI group (17.31%) was significantly (P < 0.001) lower than that noticed in both low (36.96%) and moderate THI (31.61%) groups. Meanwhile, high THI significantly increased the embryonic loss (P < 0.001) and abortion (P=0.043) rates compared with low (14.62% and 8.89%; respectively) and moderate (22.84%; and 11.17%; respectively) THI groups. The high THI group had a significantly (P=0.001) greater embryonic losses than the other groups. Conclusively, THI over 75 deteriorates the reproductive indices of Holstein cows.KEYWORDS: Holsteinheat stressTHIreproductive indices AcknowledgmentsThe authors are grateful to Dr Mohammed Abdel-Hameed, the dairy farm (station 2) manager, El Salhiya Company for investment and development, New Salhiya, Sharkia governorate, Egypt, and his team for their cooperation in this study.Authors contributionsAbdelrahman Kilany: data collection, analysis and MS drafting. Abdel-Halim El-Darawany: data collection, analysis and MS drafting. Akram El-Tarabany: data collection, analysis and MS drafting. Khaled Al-Marakby: data collection, analysis and MS drafting.Disclosure statementNo potential conflict of interest was reported by the author(s).Data availability statementAll data generated or analyzed during this study are included in this published paperEthical approvalThis work was reviewed and approved by the Animal Care and Welfare Committee of Egyptian Atomic Energy Authority standard operating procedures.