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Cows that received an over-calorie diet in the final phase of lactation are prone to liver lipidosis. The task of our research is to study the dynamics of cholesterol and triglycerides in cows with fatty hepatosis during the transit period. A group of 20 dry cows was formed. In the blood serum of cows, the concentration of cholesterol and triglycerides was studied twice before calving (15–20 days and 5–10 days) and twice after calving (5–10 days and 20–25 days). After research was formed two groups. The first group included 8 cows, which were killed 7–43 days after calving. They had signs of liver lipidosis. The diagnosis of fatty hepatosis was confirmed by the results of a histological examination of the liver. The second group included the remaining 12 cows. At the beginning of the study, the cows of the first and second groups had a cholesterol concentration of 4.06±0.23 and 3.62±0.23 mmol/l, and triglycerides - 0.13±0.01 and 0.11±0.01 mmol/l. Further dynamics of indicators had features in each group. In cows with hepatosis, a gradual decrease in cholesterol to 1.83±0.07 mmol/l was observed. In the second group the indicator was 2.2 times higher (P < 0.01). Before calving, a decrease in the concentration of triglycerides is observed. A more significant decline was detected in cows of the first group—by 61.5% (P < 0.001). In cows of the second group, the index decreased only by 18.2%. After 5–10 days after calving, the concentration of triglycerides in both groups remained low. After 20–25 days in the first group, the index increased 2.3 times (P < 0.01), and in the second—1.25 times. Studies have revealed features of the lipid profile in cows with liver lipidosis.

Dairy goats require attention and high-quality feeding during the lactation due to metabolism intensity. The metabolic rate during different lactation periods in order to better understanding production physiology in Saanen goats is the case of interest. The aim of this research was to evaluate antioxidant system characteristics in Saanen goats depending on lactation period. The experiment was conducted in the north-western region of Russian Federation, in the laboratory of the biochemistry and physiology department, FSBEI of Higher Education «SPbSAVM». The experimental group included 30 Saanen goats, 2nd–3rd lactations, selected using matched pairs method. The blood samples were taken 3 times: at the start of the lactation (2 days after parturition), at peak lactation performance (45 days after parturition) and before the interlactation period (4 months after parturition). Control group included 30 non-lactating Saanen goats, same age. The blood samples in control group animal were taken once. The blood levels of lipid peroxygenation markers (malondialdehyde, dienketone and conjugated dienes) and superoxide dismutase and catalase activity were assessed by standard methods. Results presented as mean±standard error of the mean. Student’s t-test was used after proving normal distribution. Level of significance is labeled as P < 0.05. The results are displayed in table 1 and 2. After analyzing the received data of antioxidant system characteristics the free radical oxidation highest intensity were revealed at the start of the lactation and at peak lactation performance, which indicates the development of oxidative stress in this periods. Also antioxidant enzymes’ activity was reduced during the peak lactation performance and remained at the control group level at the start of the lactation. This indicates free radical oxidation processes decompensation during the peak lactation performance. Thus, due to the development of decompensated oxidative stress in high milk producing ability animals during peak lactation, exogenous use of anti-oxidants is recommended.

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