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Background: Copper supplementation in ruminants deserves special attention because of the narrow margin between deficiency and toxicity. The aim of the study was to analyse the relationship between the Cu concentration and other blood parameter values having taken into consideration their physiological limits based on the variation of copper concentration in the three different sheep breeds. Methods: Sixty sheep (35±5 kg) kept on the same farm were studied: the Suffolk (n = 20), the Merino (n = 20) and the Lithuanian blackhead (n = 20). The sheep were selected according to the following parameters: 3.5±0.3 years old, not pregnant during the entire investigation period, clinically healthy. All sheep were kept under the same conditions and throughout the year, were fed at the same time the same ration balanced according to their physiological needs. Individual blood samples were collected on the same day, on monthly basis for the period of one year (April 2018 to May 2019). Blood biochemical parameters as well blood haematology and cortisol concentration were analysed.Result: The highest average value of copper concentration was found in the Merino breed. The study has shown that the lowest number of blood samples with the levels of copper meeting the physiological limit values was found in the native Lithuanian blackhead sheep at the end of the grazing period and in the Merino and the Suffolk breeds - during the coldest winter months. The increase in copper concentration could be related to the stress caused due to the changes in dietary conditions, the variations of ambient temperature and different breed response to these factors.

The aim of the current instant study was to evaluate relative at-line milk progesterone dynamic changes according to parity and status of reproduction and to estimate the relationship with productivity in dairy cows by at-line milk analysis system Herd NavigatorTM. According to the progesterone assay, experimental animals were divided into three periods: postpartum, after insemination, and pregnancy. In the first stage of the postpartum period, progesterone levels in milk were monitored every 5 days. This period of reproductive cycle recovery was followed for 30 days (days 0&ndash, 29). The second stage of the postpartum period (30&ndash, 65 days) lasted until cows were inseminated. In the period (0&ndash, 45 days) after cow insemination, progesterone levels were distributed according to whether or not cows became pregnant. For milk progesterone detection, the fully automated real-time progesterone analyzer Herd NavigatorTM (Lattec I/S, Hiller&oslash, d, Denmark) was used in combination with a DeLaval milking robot (DeLaval Inc., Tumba, Sweden). We found that an at-line progesterone concentration is related to different parities, reproductive statuses, and milk yield of cows: the 12.88% higher concentration of progesterone in milk was evaluated in primiparous cows. The average milk yield in non-pregnant primiparous cows was 4.64% higher, and in non-pregnant multiparous cows 6.87% higher than in pregnant cows. Pregnancy success in cows can be predicted 11&ndash, 15 days after insemination, when a significant increase in progesterone is observed in the group of pregnant cows.

Previous research has shown that the administration of non-steroidal anti-inflammatory drugs in postpartum cattle has the potential to be a viable way to improve productivity and reproduction, although further research is necessary to optimise recommendations for producers. The aim of this research was to determine the influence of carprofen on dairy cows using a number of different indices including stress, reproduction, and milk yield data. The experiment was carried out on 100 first-lactation dairy cows. The animals were divided into two groups. The treatment group (TG, n = 50) was given a subcutaneous injection of Rimadyl Cattle® (50 mg/ml of carprofen) up to one hour after calving. At the same time, the control group (CG, n = 50) was given an injection of 0.9% NaCl. Blood tests were taken 2, 24, and 48 h after calving and tested using the fluorescence enzyme immunoassay method for cortisol analysis. At 305 days, the total milk yield was recorded for each cow. A computerised herd management program was used for data registration and analysis. Pregnancy was tested by ultrasound between 30 and 35 days after insemination. A subcutaneous injection of carprofen (1.4 mg per 1 kg of body weight) given one hour after parturition in first-lactation cows reduced the level of cortisol within 48 h after calving. During lactation (305 days in milk), the intervention increased the milk yield (252 kg) and pregnancy rates (8.5%), reduced the calving interval (43 days), and decreased the somatic cell count during the second, third, and fourth months after calving.