Global Climate Change Effects on the Reproductive Efficiency, Milk Output, and Composition in Dairy Cattle

Abstract: Temperature, relative humidity, air movement, and sun radiation are climate elements that affect dairy cows. Temperature and relative air humidity are the two main factors affecting animal production. As the temperature outdoors rises, cows' primary non-evaporative cooling systems (radiation, conduction, and convection) become less effective; thus, they also depend on evaporative cooling, such as sweating and panting. An imbalance between the body's metabolic heat production and its release into the environment can lead to heat stress in uncomfortable weather. Heat stress has a detrimental effect on dairy cows' health and productivity. Climate change causes material and financial losses for farm animals, particularly in the summer months, in most regions of the world. When dairy cows are inseminated in the summer, the majority of the fertility reduction is caused by summer heat stress. Heat stress has a major detrimental impact on numerous reproductive features and, consequently, the milk output of dairy cows, which is a major financial burden in many dairy-producing regions of the world. Heat stress has a number of serious and expensive effects on dairy cows. Decreases in dry matter intake (DMI), milk output, and milk efficiency are linked to ambient temperature and temperature-humidity index (THI) increases over acute thresholds.