Negative impact of heat stress on reproduction in cows: Animal husbandry and biotechnological viewpoints: A review

This review summarises current knowledge of the relationship between heat stress (HS) and reproduction in cattle. It focuses on research from the viewpoint of genetics (breed), from the viewpoint of reproduction physiology (in vivo and in vitro) and from the animal husbandry practice. From the viewpoint of animal husbandry, it was evidenced that heat stress influences reproduction before, during and after conception. Most publications suggest the negative impact of heat stress on the reproductive physiology of cows reflected in ovarian and follicular activity, in oocyte and embryo development, as well as in other processes studied under in vivo or in vitro conditions. There are also a number of products that the cell creates in response to heat stress, which is used as indicators of the stress (e.g. heat shock proteins). A number of publications also focus on how to prevent heat stress on the farm (e.g. shade, water shower) or during in vitro procedures, including the supplementation of the culture media with antioxidants like melatonin. Research of heat stress is very important in cattle breeding for preventing and reducing its effects on the farm and also in the context of climate changes and global atmospheric warming.