Influence of high temperature on dairy productivity of Ukrainian Schwyz
In monitoring studies of recent years, global warming is reported. This is a significant problem for dairy farming in much of Europe, especially in the central and southern regions, as reported by numerous studies. Dairy cattle highly productive are extremely sensitive to hot temperatures; their consequence is health problems, a significant reduction in milk yield and milk quality. Unfortunately, heat stress remains an unrecognized problem for domestic cattle breeding, although the financial losses from its harmful influence in European are quite substantial. The aim of our work was to study the effect of high temperatures on milk yield of cows of Ukrainian Schwitz on one of the complexes of high-tech milk production. At the beginning of the research, we decided to test the hypothesis of increasing hot air temperatures in the warm period of the year compared with the long-term data. Then we studied how the milk of Schwitz breed varies during the hot season, depending on the magnitude of the maximum temperature values. According to the results of the study, it can be noted that the air temperature during the warm period of 2017 tended to increase (+0.6 °С) in comparison with the long-term data. In August, the air temperature significantly exceeded the long-term data by +3 °C (td = 2.89, P < 0.05). The relationship between the temperature and milk yield of cows is revealed by an average degree of reliability (r = -0.45, P < 0.05). Compared with the most favorable external conditions in May, the cows' milk yield decreased in June by 3.0%, the yield of milk fat by 5.2%, the milk protein content by 3.4% (P < 0.001). In July and August, the cows' milk yield decreased by 4.6 and 5.5% (P < 0.001), the yield of milk fat decreased by 3.1 and 7.3% (P < 0.01–0.001), the yield of milk protein 3.4 and 5.7% (P < 0.001). Thus, high temperatures during the summer period contributed to a decrease in milk yield and the main components of milk of the Ukrainian Schwitz, which can lead to tangible financial losses.