Assessing the freshwater fluxes related to beef cattle production: A comparison of integrated crop-livestock systems and a conventional grazing system

Abstract

Beef production is one of the largest water consumers of all food production systems, but there are substantial knowledge gaps about the accounting and interpretation of its freshwater consumption. Moreover, hardly any study has assessed the freshwater fluxes related to beef cattle in integrated crop-livestock (ICL) and crop-livestock-forestry (ICLF) systems. We aimed at quantifying the freshwater fluxes related to beef cattle raised on continuous permanent Brachiaria pastures (CON) or in ICL and ICLF systems in the Brazilian Cerrado in the rainy and dry seasons. Evapotranspiration of forage grass, Eucalyptus trees in ICLF, and from drinking water troughs were calculated from meteorological data collected in the field. Forage accumulation was measured in 11 paddocks over both seasons, and forage intake, drinking water intake, and bodyweight were quantified in 12 growing Nellore heifers per system during two months per season. Freshwater fluxes related to forage production and animals were estimated. Drinking water intake and water intake via forage did not differ (P ≥ 0.073) between the systems, and were greater (P ≤ 0.035) in the rainy than the dry season. Faecal and urinary water excretions were greater in the dry than the rainy season (P ≤ 0.005). The respiratory and cutaneous water losses were greater (P < 0.001) in the rainy than the dry season. In the rainy season, evapotranspiration related to forage accumulation and freshwater consumption for raising beef cattle were greatest in CON, whereas they were greatest in ICLF in the dry season. Although ICLF appeared to be less resilient to dry periods, both integrated systems offer the potential for reduced freshwater consumption for raising beef cattle under grazing conditions, by improving the efficiency of forage use and/or decreasing evapotranspiration of forage.