Effect of heat-stress on conception in a dairy-herd model in the Natal highlands of South Africa
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Date
Authors
Du Preez, J.H.
Willemse, J.J.C.
Van Ark, H.
Journal Title
Journal ISSN
Volume Title
Publisher
Published by the Agricultural Research Council, Onderstepoort Veterinary Institute
Abstract
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 + 28,61THI - 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 = 0,1 06). 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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Keywords
Veterinary medicine, Friesian cattle, Lidgetton
Sustainable Development Goals
Citation
Du Preez, JH, Willemse, JJC & Van Ark, H 1994, 'Effect of heat-stress on conception in a dairy-herd model in the Natal highlands of South Africa', Onderstepoort Journal of Veterinary Research, vol. 61, no. 1, pp. 1-6.