Author/Authors :
Nyamushamba، G.B. نويسنده Faculty of Agriculture, Women’s University in Africa, P.O Box, MP 1222, Mt Pleasant, Harare, Zimbabwe. , , Tavirimirwa، B. نويسنده Department of Research and Specialist Services, Matopos Research Institute P Bag k5137, Bulawayo, Zimbabwe. , , Banana، N.Y.D. نويسنده Faculty of Natural Resources Management and Agriculture, Midlands State University, Gweru, Zimbabwe ,
Abstract :
Milk production is affected by genetic and non-genetic factors. Knowledge of these factors is essential for efficient management and accurate estimation of breeding values. The objective of this study was to establish and analyze non-genetic factors which affect milk production and composition in Holstein-Friesian cows. A total of 4 500 milk records from the Zimbabwe Dairy Services Agency (ZDSA) from 1999 to 2004, were used. Natural ecological region, month of calving and year of calving had significant (P < 0.05) effect on milk yield, protein and fat composition. Therefore, correction for environmental effects is necessary to increase accuracy of direct selection for milk yield and composition.
