Comparison of lactation descriptive models and the study of the effect of some non-genetic factors on lactation parameters in Buffalo

The aim of this study was to compare the Wood, Dijkstra and Sineus models for fitting the lactation curve of the first abdomen of Khuzestan Buffalo. The effect of fix factor such as year, season and herd on the curve of milk parameters were studied. In this study, 73169 test day records of milk were used. Records were collected in the animal breeding center. According to the test day record and using different initial values, using SAS software and NLIN procedure were estimated the parameters of each lactation models. R2adj, AIC, MSE, RMSE and Iterations were used for comparison of models. The results of the model's comparison were showed that all three models of Wood, Dijkstra and Sinus were able to fit the buffalo curve. But the Wood model, having the lowest AIC, MSE and RMSE was goodness than the other two models. The mean of Wood parameters such as a, b and c were 2.36, 0.656 and 0.0009 were respectively. Average the peak of lactation was 84 days. The most and least lactation continuous was in summer and spring, respectively (p<0.05). All Wood parameters and lactation indexes were affected year, herd and their interaction (p<0.05). By using the lactation curve and determining the components of lactation, it is possible to plan for feeding and management of buffaloes.