Efecto de la disponibilidad diaria de hierba sobre la producción y calidad del pasto y de la leche en vacuno

Resumo

We studied the effect of two levels of herbage mass on livestock performance of two dairy herds(n = 72), two stocking rates were examined through the application of two levels of daily herbage allowance,(H) high 30 or (L) low 23 kg DM cow-1 day-1. We determined the evolution on pasture productionand quality during the spring grazing season (H, 4 vs. L, 5 rotations), and milk yield, similar inboth treatments (H, 25.3 vs. L, 24.9 kg cow-1 day-1), as well as pasture intake (H, 14.9 vs. L, 13.6kg DM cow-1 day-1). Increasing the stocking rate (H, 4.0 vs. L, 5.2 cows/ha), with lower herbage mass(H, 3,116 vs. 2,288 kg DM/ha), improved the quality of the pasture on offer. The high stocking ratereduced the length of rotation, the sward height (p<0,05) pre- (H, 19.5 vs. , 16.3 cm) and post-grazing(H, 7.4 vs. L, 6.6 cm), and showed lower DM content (H, 18.0 vs. L, 16.8 %) and fibers, and atthe same time increased (p<0.05) the crude protein content (H, 138 vs. L, 153 g/kg), the carbohydratesand the digestibility of the DM. Applying the high stocking rate also resulted in higher (p<0,001)milk protein content (H, 29.9 vs. L, 30.7 g/kg) and fat content.