Effect of the management method and access to the drinking trough on the water intake of grazing cattle

Thirty Holstein crossbreds calves of 128 to 137 kg LW grazing as leaders (L and 28 yearlings from 201 to 219 kg LW grazing as followers (F) were used. This scheme was repeated in a rotational grazing with 4 paddocks (RG4) and in another with 8 paddocks (RG8). A group of steers of 327 kg was introduced (trimmer T) to reduce the surplus pasture when necessary. To determine water intake under these management conditions, acess to the drinking troughs was established for 3 hr one (1 day) or for 2 hr twice daily (2 days) within each L and F groups. Water intake was measured every 14 days. Pasture yield was measured three times. The animals were weighed at the beginning and end of the 162 day experimental period between May and October. A model of hierarchical effects was used controlling treatment, animal category and animals within each treatment. Water intake increased (P <0.01) with live weight until 18.6, 25.6 and 38.8 liters/animal/day as average for L, F and T, respectively. Based on pasture yield and intake estimates, total water intake of cattle In tropical pastures could be between 20 and 30% higher than the available recommendations. Data on animal performance under similar management conditions are shown to propose the absence of bias attributable to access restrictions to the drinking troughs.