Effect of non-genetic factors on milk yields traits in Simmental cows raised subtropical climate condition

ABSTRACT The aim of this study was to identify non-genetic parameters affecting the milk yield traits of Simmental cows raised in subtropical climate conditions. Records on 1904 lactation events of Simmental cows (N=706) during 2001-2014 were included in this study. A generalized linear model was used to investigate the effect of non-genetic factors (calving year, season, and age; lactation number; birth type; and calf sex) on real milk yield (MY), adjusted 305-d lactation milk yield (305-d MY), adjusted mature-age 305-d lactation milk yield (305-d MAMY), lactation length (LL), and dry periods (DP). The MY, 305-d MY, 305-d MAMY, LL, and DP were 6413.04kg, 6060.30kg, 6871.21 kg, 329.88d, and 57.67d, respectively, in Simmental cows. The effects of calving year, birth type, and calf sex on MY were significant (P