Behaviour of 5/8 Holstein-3/8 Zebu cows submitted to Voisin Rational Grazing and to variable strip grazing systems under low input conditions

The influence of the grazing method on the behaviour of 5/8 Holstein-3/8 Zebu cows, was studied in forty animals distributed in a completely randomized design under the rational gazing systems of Voisin's and variable strip grazing in a dairy farm under low input conditions. The in -line grazing was applied with lactating and pregnant close to calvin,a cows, as leaders and the rest as followers. Grazing intensity was variable, according to the pasture response. Leaders had limited access to the protein bank and the followers to king grass gazing. Grazing was interrupted from 11 a.m. to 3 p.m. in both seasons. There was no interaction when the group of animals in any of the controlled. There was a significant interaction between the grazing method and the season in periods gazing and drinking, as well as in pasture availability, grazing intensity and pressure. There was a grazing period of over 9 hr in the variable strip method during the dry season, when the availability decreased and the grazing pressure increased. The behaviour pattern was maintained in the rest of the treatments. In general, the highest percentage gazed in the morning was lower in the rainy season and, the lowest proportion of animals grazed at night in the rainy season. Rational gazing allows for the behaviour pattern of grazing dairy cows. The behavior varies with the grazing method, provided pasture availability is reduced and grazing pressure is increased. Under these conditions feed availability is more important than the direct effect of the climate when the access to the grassland is I limited at the most critical hours. Results allow to suggest the increase of biomass supply in the most critical period of the year.