Efeito do uso de sombra no comportamento social e ingestivo de bovinos de corte terminados em sistema de confinamento

Abstract

The aim of this study was to evaluate the effect of artificial shade on the social and ingestive behavior of feedlot beef cattle. A total of 900 male Nellore non-castrated cattle with initial mean live weight of 380 ± 30 kg and 24 months of age were allocated to three artificially shaded pens (Tshade) and three without shadings (Tsun). The assessment of social and ingestive behavior was performed by recording the number of displacement (DI), mount (MO), fights (FI) and head-play (HP) and percentage of animals in the feed trough (PFT) and in the drinking water (PDW). During the first two weeks of confinement, the evaluations of the variables were performed at two-day intervals during the adaptation period and then biweekly, between 7 am and 11 am and 1 pm until 5 pm. To evaluate the effects of treatment on , MO, DI, HP, FI, PFT and PDW, the PROC MIXED command of the SAS statistical program was used in a repeated measurement analysis over the confinement days, for the adaptation, the post-adaptation and day periods (DP = morning and afternoon). The means were adjusted by Tukey test. There was a significant effect of the interaction between treatment and confinement day, within the adaptation period, for the number of occurrences of FI (P = 0.005) and MO (P = 0.0004). the highest occurrence in Tsun and in the early days of confinement. During the adaptation period, there was a treatment effect on the PDW, and Tsun animals accessed the water more than Tshade (1.49% and 1.09%, respectively; P = 0.04). In the evaluation of the post-adaptation period, the confinement day was significant for the variables PFT, DI and HP (P <0.05) and the values decreased over time. There was a DP effect for the PDW, PFT, FI and HP variables (P <0.05), when PDW = 14.70% and 18.09%; PFT = 1.22% and 1.37%; FI = 0.77 and 0.46; HP = 2.60 and 3.76, for the morning and afternoon, respectively. The treatment had only significant effect according to DP for PDW (P = 0.04), being higher in Tsun compared to Tshade (1.49% and 1.09%, respectively).