The goal of this investigation was to study the influence of different values of Temperature-Humidity index (THI) on the duration of lying down and feed consumption, productivity, and heat production by dairy cows in two variants of feedlots (with and without shelters). The study was conducted from February 2007 to early August 2021 in the central part of Ukraine (Kyiv region) in different periods of THI. This index was divided into three categories: 1) 66–71: normal (14 days); 2) 72–79: alert (11 days); 3) >80: dangerous (9 days). Two variants of feedlots were selected: Open feedlot with shelters and open feedlot without shelters. The largest increase in values of THI affecting the cows was observed in open feedlots without shelters. There, in alert and danger periods duration of feed consumption decreased by 8.0 and 23.1 min, lying down by 17 and 38 min, productivity by 2.3 kg (...

The aim of this study was to investigate the impact of fan cooling during high-temperature periods on barn microclimate, cow productivity, milk composition, and clinical indicators. The research was conducted at a commercial farm (Ukraine) where dairy cows were kept in two easy-to-assemble barns (with and without fans) during thermo-neutral and hot periods. The use of fans in the cowshed during the hot period helped to reduce the average daily temperature and relative humidity by 3.29 ºC and 1.88%. Indicators of rectal temperature and respiration rate at keeping in a barn with the use of fans were respectively: 0.35 ºC and 8.36 breaths/min compared to a barn without fans. The average milk yield in a barn with fans during the hot period decreased by 0.37 kg, and in a barn without fans by 2.64 kg compared to the thermo-neutral period. When keeping cows in a barn with fans during the hot ...