Knowledge and perception of milk producers about thermal stress in Brazilian dairy farms.

Heat stress is a challenge for the milk production chain, especially in tropical environments. Thus, the objective was to evaluate the knowledge and the perception of milk producers about heat stress and determine what corrective measures they adopted to minimize losses in the productive performance of dairy cows due to high temperatures. A questionnaire was applied to 112 dairy farmers in the states of Minas Gerais and Goiás, Brazil in 2019 and 2020.

Heat wave exposure impairs reproductive performance in primiparous sows and gilts in a tropical environment.

We studied the effects of heat waves (HW), defined as three consecutive days with an ambient temperature ≥ 25 °C and a temperature and humidity index (THI) > 74, on the reproductive performance of sows. Meteorological data were obtained from the National Institute of Meteorology and reproductive data from a commercial farm with 51,578 inseminations and 49,103 pregnancies from September 5, 2013, to July 12, 2019. Sows were divided into the following groups according to the parity order: group 1 (sows that did not experience HW on the day of insemination) and group 2 (sows exposed to HW on the day of insemination).

Effect of cyclic heat stress on thyroidal hormones, thyroid histology, and performance of two broiler strains.

This study determined thyroid hormone (T and T) serum levels and investigated thyroid gland histology, as well as two broiler strains performance kept at different periods of heat stress. Broilers (560 Cobb Slow™ and 560 Hubbard Flex™) were distributed in control environment (0) reared following the thermal recommendations, and environments 1, 2, and 3 exposed to high temperatures for 1 h, 2 h, and 3 h a day, respectively, from 14 to 42 days old. At 21, 28, 35, and 42 days old, blood samples were collected to determine T and T serum levels.

Can Bos indicus cattle breeds be discriminated by differences in the changes of their sweat gland traits across summer and winter seasons?

This study addresses the hypothesis that Bos indicus cattle breeds can be discriminated by the changes that occur in their sweat gland traits between summer and winter seasons in tropical conditions. Samples of the skin were taken from six Bos indicus cattle breeds (eight subjects per breed), including Nellore, Cangaian, Gyr, Guzerat, Punganur, and Sindhi in winter and summer. The sweat gland epithelium (μm), glandular portion length (μm), sweat gland duct length (μm), gland depth (μm), and sweat gland density (cm) were determined.