EFFECT OF DRINKING-WATER IN PADDOCKS ON THE PERFORMANCE OF HOLSTEIN CATTLE AND STAR GRASS

Thirty Holstein cows with a potential of 3800 to 4500 litres/lactation grazing Star grass (Cynodon nlemfuensis) were used to study the possi ble effect of the water supplied in the paddocks on the performance of animals and pastures. A multiplicative model was used for the statist ical analysis of milk production, protein and milk fat, which controll ed the lactation curve, treatment, production bimester, year and seaso n, while a linear model of fixed effects (treatment, year, season) was used to analyze the quality and availability of pasture, water consum ption, lactose, solids non-fat and total solids. Total drinking water consumption increased (P < 0.001) in 12.7 litres/cows/day when water w as supplied in the grazing area (32.9 vs 45.6 litres/cows/day). Pastur e availability and height augmented (P < 0.01) as well as the number o f fertility points (P < 0.05) when animals had access to water in the paddocks (589 vs 51.6 g/DM/m(2); 31.3 vs 27.6 cm and 589.2 vs 432.8 po ints/ha). Milk production increased 0.7 kg/cow/day with water in paddo cks (P < 0.001) (8.9 vs 8.2 kg/cows/day). Neither pasture quality nor milk composition were affected. This paper suggests a possible positiv e effect on productive performance and pasture when supplying drinking water in paddocks.