Aspectos comportamentais de bovinos da raça Angus a pasto frente à disponibilidade de recursos de sombra e água para imersão. / Behavioral patterns of Angus beef cattle under grazing conditions with availability of shade and water for immersion.

AUTOR(ES)
DATA DE PUBLICAÇÃO

2003

RESUMO

Cattle, including Bos taurus and Bos indicus, under grazing conditions in tropical areas, seek shade during the hottest periods of the day. The objective of this study was to understand how Angus bulls use the thermal well-being resources, quantifying the frequencies of utilization of shade and water for immersion (pond), available in the pasture, evaluation the causes and functions of different behaviors, detecting the preferences for shade or water for immersion, or interactions of both. The experiment was conducted at the Universidade de São Paulo, Campus of Pirassununga. The behavioral patterns of eight young bulls (400 Kg live weight, 14 months of age), four with shorter hair length and four with longer hair length (>1,30 cm), were evaluated in three different treatments: availability of natural and artificial shade (TS), availability of artificial shade and water for immersion (TSA) and availability of water for immersion (TA). The air temperature, relative humidity, solar radiation, and the black globe temperature were registered for all experimental periods. The average maximum air temperature was 32C and the black globe value was 45C. The highest value for the black globe-humidity index varied from 92 to 96. The behavioral patterns were recorded using the focal sampling method, every 15 minutes, from 8h00 a.m. to 6h00 p.m., and the categories observed were the position (in the sun, in the shade or in the water), the posture (standing or lying down) and the activities (grazing, ruminating, moving, resting or other). The results showed that the number of events of animals in the sun were considerably reduced from 12h00 a.m. to 2h00 p.m., for both treatments. The main activity occurring in the sun was grazing, especially concentrated during the cooler times of the day. When the animals were in the TSA treatment, they preferred to use the shade as a resource against the heat load. The pond was used often from 2h00 p.m. to 3h00 p.m. (TSA) and from 8h00 a.m. to 3h00 p.m. for TA. On a whole, the animals with shorter hair length utilized the thermal well-being resources less than the animals with longer hair. Under grazing conditions in hot climates, resources for defense against heat load are essential to improve the wellbeing conditions for cattle.

ASSUNTO(S)

comportamento animal pastejo gado angus angus welfare bem-estar animal grazing cattle thermoregulation termorregulação behavior

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