Respostas fisiológicas, comportamentais, desempenho e qualidade de carcaça e carne de ovinos mestiços confinados com e sem acesso ao sombreamento artificial

Abstract

The objective of this project was to evaluate the influence of artificial shading of polypropylene mesh with 80% light interception on physiological, behavioral, performance, productive and carcass and meat characteristics of lambs in intensive system. The experiment was carried out in a confinement of the School Farm of the State University of Goiás, São Luís de Montes Belos Câmpus, Goiás, Brazil, with a duration of 70 days, being 14 days of adaptation of the animals to the experimental environment. Twenty male Santa Inês x Dorper crossbred sheep, with an average weight of 25 kg, were confined. Respiratory rate, surface temperature, room temperature and relative humidity were evaluated once a week. Once a week, the behavioral assessment was also performed, beginning at 07:00 and ending at 19:00, and fortnightly weighing and rectal temperature of the sheep. Eating behavior, rumination, rest and sleep were evaluated, among other activities, which included social, playful, locomotion and abnormal behaviors. At the beginning of the experiment the animals were weighed fortnightly, and carcass development was evaluated by ultrasound analysis at the beginning and end of the confinement. The diet consisted of concentrate and roughage provided at four times during the day. After 70 days of confinement, the animals were slaughtered for carcass and meat evaluations. The results of all environmental, physiological and behavioral variables evaluated in relation to the treatments were not presented significant differences, but the animals presented high respiratory rate value, due to the high UTI value. For the productive evaluations, carcass characteristics and meat quality were not observed significant differences in both treatments. However, the artificial shading implantation did not present significant difference in the physiological, behavioral and productive characteristics of feedlot lambs, where the ambient temperature presented during the experimental period within the considered range of thermal comfort to the sheep, what made the animals were in homeothermia.