An Automated Sprinkler Cooling System Effectively Alleviates Heat Stress in Dairy Cows

Simple Summary Heat stress detrimentally affects dairy cows, resulting in economic losses during dairy production. Therefore, this study aimed to evaluate the effects of an automatic spraying method on alleviating heat stress in cows and identifying potential mechanisms. Our findings showed that the automated sprinkler cooling system treatment effectively reduced body temperatures, improved milk yield and quality, enhanced rumen fermentability, modulated rumen microbial communities, and significantly proliferated carbohydrate-degrading bacteria. Moreover, our study demonstrated that the automatic spraying cooling system had modulatory effects on rumen microbiota composition and fermentation function, and causatively ameliorated the side effects of heat stress in dairy cows.Abstract (1) Background: Heat stress detrimentally restricted economic growth in dairy production. In particular, the cooling mechanism of the spraying system effectively reduced both environmental and shell temperatures. This study was designed to investigate the underlying modulatory mechanism of an automatic cooling system in alleviating heat-stressed dairy cows. (2) Methods: A total of 1208 multiparous dairy cows was randomly allocated into six barns, three of which were equipped with automatic sprinklers (SPs), while the other three were considered the controls (CONs). Each barn was considered a replicate. (3) Results: Body temperatures and milk somatic cell counts significantly decreased, while DMI, milk yield, and milk fat content significantly increased under SP treatment. Rumen fermentability was enhanced, embodied by the increased levels of total VFA, acetate, propionate, and butyrate after SP treatment. The rumen microbiota results showed the relative abundances of fiber-degrading bacteria, including the Fibrobacters, Saccharofermentans, Lachnospira, Pseudobutyrivibrio, Selenomonas, and Succinivibrio, which significantly increased after receiving the SP treatment. (4) Conclusions: This study demonstrated that SP effectively alleviated heat stress and improved production performances and milk quality through modulating the rumen microbiota composition and fermentation function of dairy cows.