Seasonal effect on productivity of Bali cows in oil palm plantation in Riau Province, Indonesia

This study was aimed to assess the effect of seasons on the productivity of Bali cows kept in oil palm plantation (OPP). The study used 20 Bali cows and 1 bull, which kept semi-intensively without supplementary feeding. Cow's reproductive data, grouped according to birth time, dry season (DS) (May-October) and the rainy season (RS) (November-April) from August 2016 to September 2018, were used. These data were used to determine calving interval and calf mortality. Cows were weighed monthly to estimate dry matter consumption, which was calculated using the Minson equations. Calves were weighed at birth and weaning. Cow's reproductive index (CRI) and cow's productivity index (CPI) were calculated based on reproductive data and weaning weight. Data were analysed using One way ANOVA. The result showed that during the DS, the consumption was better (1.96BW) compared to the RS (1.83BW) (P<0.01). Calf mortality was higher in the RS (19.05) than the in DS (17.65), due to high rainfall and humidity. During the two seasons, calving interval, birth and weaning weights, CRI and CPI of Bali cattle in OPP were relatively similar. It is concluded that the seasons did not influence productivity of Bali cows kept in OPP.