Termorregulação de cordeiros mestiços Dorper/Santa Inês nosSistemas intensivo: em pasto e confinado

This study aims to compare the physiological parameters of Dorper/Santa Inês crossbred lambs and the microclimate of intensive systems in environments with ceramic tile roofing (confinement) and open-air environments (pasture). Twelve ½ blood Dorper/Santa Inês lambs were used, weaned at 60 days, with an average weight of 19.42 kg. The factorial design included 2 environments (confined and pasture), 2 periods (morning and afternoon), and 2 times points (January and February), totaling 8 treatments. In confinement, the lambs were housed in a collective pen of 36 m² with ceramic tile roofing and a concrete floor, while in the pasture, Panicum maximum cv. Massai was provided in an open-air, rotated paddock. The animals showed significant differences (P<0.05) compared to the animals on pasture, both between the months in which the samples were collected and during the morning and afternoon periods. The animals in confinement also showed significant differences (P<0.05) between the morning and afternoon periods. The THI proved to be more challenging during the afternoon period and in pasture environments, highlighting the need for management strategies that include shading and other forms of protection against direct solar radiation. The respiratory and heart rates of the lambs were higher during the afternoon period, suggesting insufficient adaptation to high temperatures. Furthermore, the variations in the rectal and surface temperatures of the animals corroborate the direct influence ofclimatic conditions on thermal regulation.