No abstract

The relationships between the urea and other goat milk indicators levels at the beginning of lactation on intensive production and with a certain level of feeding were revealed. Due to the beneficial effects on human health, goat's milk has found its niche in healthy foods' assortment of developed countries. A sampling of milk has provided an opportunity to identify the characteristics of the goat milk's physicochemical composition at the beginning of lactation (the first week, the first and second months after parturition). Evaluation of the goat milk quality has high economic importance, especially protein and fat content, on which the volume of produced cheese depends. The milk urea content was 20.93 ± 8.8 mg/dl, the fluctuations at the end of the first week were 10.57 ± 5.78 mg/dl, and the second month of lactation was 25.08 ± 3.17 mg/dl. A correlation was observed between this indicator and the content of fat (r =-0.62), protein (r =-0.76), dry matter (r =-0.72), milk solids-non-fat (r =-0.75) and the milk freezing point (r =-0.79). Thus, these results differ from the data of other researchers conducted with milk and obtained in other lactation periods, when these dependencies were already offset by the influence of other factors. The level of fat averaged 4.77 ± 1.43%, protein 3.61 ± 0.98%, fat / protein ratio was 1.34 ± 0.27. At the end of the first week, level of fat was 5.86 + 1.73%, protein 4.65 ± 0.91%, fat / protein ratio 1.26 ± 0.28, and in the second month of lactation 4.40 ± 1.10%, 3.07 ± 0.51% and 1.43 ± 0.24, respectively. This is probably connected with a gradual transition to the production of more diluted milk after an early lactation period. But the fat and protein ratio characterizes the gradual improvement in the milk technological properties. The lactose level averaged 4.26 ± 0.22%, it varied from 4.25 ± 0.19% at the end of the first week, to 4.39 ± 0.19% at the second-month lactation. In our work, we obtained fluctuations in the number of somatic cells 3312 ± 5579 thousand/ml with very significant fluctuations in individual animals in the absence of any pathological clinical signs. Significant differences with the data from other works are probably due to the early lactation period of our animals. The solids' content in the milk averaged 13.73 ± 2.41%, milk solids-nonfat 8.94 ± 1.11%, the freezing point or mild depression was 0.563 ± 0.029 ° C. At the end of the first week, these indicators were 15,98 ± 2.44%, 10.11 ± 0.91% and-0.593 ± 0.020 ° C, and in the second month of lactation 12.89 ± 1.74%, 8.47 ± 0.75% and-0.555 ± 0.025 °C, respectively.

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.