Сечовина та інші показники молока в ранній період лактації кіз в умовах господарства степової зони України

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-non-fat 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.