Changes in the goat’s milk composition due to heat stress at the farm of the Ukrainian steppe zone

The aim of the study was to identify the relationship between milk indicators of dairy goats that are staying under heat stress with the climatic conditions of the Ukrainian steppe zone. The main research areas of animals’ reaction to temperature stress were monitoring their physiological state, changes in behavior and metabolism through the neuroendocrine mechanisms of their regulation, assessing the immune system functional state, the antioxidant defense system, and determining the activity of the microbiota of the gastrointestinal tract. It is important to control the respiratory rate of animals, which becomes especially important when the air humidity is high and the reversal of the fat/protein ratio in milk is detected. It occurs under stressful conditions and significantly affects the technological properties of milk, especially in animals with high milk productivity. It is useful to provide goats after kidding with the opportunity to stay for a long time with an adequate photoperiod, this will affect the synthesis of prolactin and the level of milk yield at the peak of lactation. When feeding highly productive animals, it becomes important to regulate both the appetite of animals and the composition of the diet. This is important to prevent digestive disorders because the state of the ruminant stomach microbiota of the feed affects the synthesis of the constituent components of milk. When breeding, attention should be paid to multiple pregnancies, because the long-term effect of gonadotropins and other biologically active substances from the placenta affects the ability of females to produce greater milk secretion in the next lactation. According to the obtained results, staying in the transition zone according to the THI (more than 65) affected some of the chemical parameters of goat’s milk. In particular, there was a decrease in fat content, and therefore also the dry matter content and the fat/protein ratio, as well as urea, as one of the indicators of the rumen microbiota state. A significant increase in the number of somatic cells was observed almost three times, which confirms the presence of stress response from the mammary gland. For an objective assessment of the animals’ welfare state in terms of climatic conditions, it is advisable to use the definitions of the temperature-humidity index, and to confirm the stress response in dairy goats from any factor of keeping and feeding – laboratory determination of stress biomarkers in the composition of blood, milk, and urine.