Water intake of Brangus cattle confined in the subtropics

• Published in: Livestock science Vol. 254; p. 104742
• Main Authors: Machado, Angélica Tarouco, da Silva, Carolina Silveira, Vieira, Aline Cardoso, Angelo, Isabelle Damé Veber, Bettencourt, Arthur Fernandes, Tarouco, Jaime Urdapiletta, Fischer, Vivian
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-12-2021
• Subjects: Beef cattle; Drinking behavior; Subtropical; Water intake prediction; Beef cattle; Subtropical; Water intake prediction; Drinking behavior
• ISSN: 1871-1413; 1878-0490
• DOI: 10.1016/j.livsci.2021.104742

•Water intake of Brangus in the subtropics is overestimated with previous models.•Inclusion of behavioral variables explain better variation in water intake.•Behavioral variables do not improve prediction models for water intake.
Water is necessary to maintain life, improve feed intake (FI) and performance of animals. This study evaluated water intake (WI) and behavior at the feeder and drinker of confined Brangus cattle in the subtropics, as well the adequacy of previously published WI prediction equations. Two trials were carried out from 2017 to 2018, with 60 Brangus heifers with an initial body weight (BW) of 229 ± 25.7 kg and with 30 Brangus calves with an initial BW of 224 ± 27.7 kg. In each trial, FI and WI were recorded for 70 days using automatic feeders and drinkers. The prediction of WI using the current equations was tested using simple linear regression between the observed and predicted WI values. Water intake was overestimated by all equations, but the differences between observed and predicted WI values were smaller with the equation using data generated with Nellore cattle. Environmental and breed-related differences and measurement equipment may explain part of these differences. The new WI prediction equations calculated with data generated in the present study including or not behavioral variables showed the highest determination coefficients for heifers (0.58 and 0.44, respectively) and calves (0.32 and 0.44, respectively). The predictor variables included in the new equations were FI, relative humidity, THI, BW, maximum temperature, number of visits to the drinkers or feeders with ingestion, water intake time for heifers. The predictors for calves were: FI, relative humidity, maximum temperature, wind speed, solar radiation and number of visits to the drinker with WI. The new prediction models for WI developed with the inclusion of behavioral variables did not improved the predictive capacity, when tested with an extra dataset collected with Brangus calves. Most of the previously published prediction equations overestimate WI, except those dealing with Zebu crossbred animals in the subtropics and tropics. Prediction equations explained less than 30–40% of the variation in WI, and therefore more studies are necessary to assess the factors affecting water ingestion and to reduce variability at the drinkers.