The Impact Of Breed, Testing Time And Metabolic Profile On The Variation Of Copper Concentration In Sheep Blood Serum

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.