Adaptabilidade fisiológica e reprodutiva de ovinos Dorper às condições climáticas do semiárido paraibano

This study aimed to evaluate the physiological and reproductive adaptability of Dorper sheep raised in the semi-arid region of Paraíba, considering the dry and rainy seasons. Six Dorper rams, aged between two and three years, were subjected to general clinical examination and andrological evaluation. The experiment was conducted during two distinct periods: the dry season (September to December 2016) and the rainy season (April to July 2017). Throughout the experimental period, climatological data were recorded using a HOBO-type datalogger with an external probe coupled to a black globe thermometer. Physiological variables were assessed fortnightly, with two daily measurements (9:00 a.m. and 3:00 p.m.), including respiratory rate, rectal temperature, mean and maximum body surface temperature, and testicular surface temperature. Blood glucose levels and andrological parameters were also evaluated fortnightly. The results indicated that during the rainy season and in the morning period, animals were under thermal comfort conditions, whereas during the dry season, especially in the afternoon, thermal discomfort was observed. Mean values of respiratory rate, rectal temperature, and mean and maximum body surface temperatures were higher during the dry season. Scrotal circumference values remained within the expected range for the animals’ age. However, the mean percentage of total sperm defects during the dry season exceeded the desirable seminal standards for the species. Among the seminal parameters evaluated, only semen volume differed between the dry and rainy seasons. It is concluded that Dorper sheep raised in the semi-arid region of Paraíba exhibit good physiological adaptability to regional climatic conditions, with low overall thermal stress, although increased ambient temperature during the dry season negatively affects reproductive parameters, particularly semen quality, resulting in a higher incidence of sperm abnormalities.