Effect of heat stress on conception in a dairy-herd model in the Natal highlands of South Africa.

نویسندگان

  • J H Du Preez
  • J J Willemse
  • H Van Ark
چکیده

Regression models are proposed for predicting conception rate in a dairy herd under South African and especially Natal conditions. Conception rate (CR%) was related to mean monthly temperature-humidity index (THI) by curvilinear regression equation model; CR% = 812.7 +/- 28.61 THI - 0.2322THI2 (P = 0.061), and by linear regression equation model; CR% = 188.0 - 1.906THI (P = 0.023). Conception rate was related to numerical month of the year (M) by: CR% = 44.34 + 6.168M - 0.428M2 (P = 0.106). Further investigations to test the proposed regression models under various dairy-herd conditions and to improve reproduction in South African dairy herds are needed.

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عنوان ژورنال:
  • The Onderstepoort journal of veterinary research

دوره 61 1  شماره 

صفحات  -

تاریخ انتشار 1994