Examine the lactation curve for crossbreed cows under intensive dairy farming condition

Abstract

The study was conducted to develop lactation curve for crossbred cows and to choose suitable mathematical models of lactation curves using fit statistics. For this study data was collected from a dairy farm named Molla dairy farm situated at Chittagong , Bangladesh from May 2015 to October 2015. The mean and standard error for 210 days milk yield of Holistein- Friesian × Local cows were analysed using PROG GLM of SAS (2012). Two lactation curve models were used to predict the 210 days milk yield from the milk recording. The average milk yield is highest at September month which was 13.68 liter and lowest milk yield at June month with 10.8 liter per cow per day. Calving interval was worse for lactation7 (3.9±1.03 years) and better for lactation5 (3.05±1.7 years). Age at first calving at lactation6 was 3.67±01.98 years and at lactation7 it was 2.77±1.26 years. . The Predicted Milk Yield (PMY) and Actual Milk Yield (AMY) for different models were varied with lactation number, season, age of first calving, and calving interval). Fit statistics (R2: Co-efficient of determinant, RMSE: Root Mean Square Error, CV: Co- efficient of variation) were used. Finally Wood model is more suitable.