Effect of different environmental factors on selected blood minerals in sheep

Aim of this study was to confirm the hypotheses that calcium, phosphorus, copper and zinc contents in blood plasma of sheep are influenced by altitude, season, breed, management system and herd. The ewes were kept in three herds, at two systems, and at four altitudes. Blood samples were divided according to following factors: Altitude (550 m, 800 m, 910 m, 950 m above sea level), Sea­son of the year (spring 2004, autumn 2004, spring 2005, autumn 2005), Season (spring, autumn), Breed (Merinolandschaf, Charo­lais, Sumavian sheep), System (ecological, non-ecological), and Herd (three herds). Concentration of phosphorus was significantly increased in altitude of 800 m above sea level (2.46 mg per l). Significant differences were recorded within the factors Season of year and Season, due to lower levels of calcium in the autumn 2004 (2.27 mg per l) and phosphorus in the spring 2005 (1.36 mg per l). The highest concentrations of phosphorus were recorded within the factors Breed and Herd, as a result of Merinolandschaf (or herd 1) (2.46 mg per l). Higher levels of phosphorus were found in non-ecological system (1.77 mg per l vs. 1.36 mg per l). The copper and zinc concentrations were affected by the factor Altitude (P less than 0.001). The lowest level of copper was recorded in the spring 2004 (11.65 micro mol per l); between spring and autumn (factor Season) a significant difference was recorded in zinc (15.08 micro mol per l vs. 17.00 micro mol per l; P less than 0.01). The highest value of copper was measured in the Charolais sheep (17.64 micro mol per l), the highest concentration of zinc in the Sumavian sheep (17.34 micro mol per l) and the lowest one in the Charolais sheep (14.68 micro mol per l; P less than 0.01). The higher copper con­centration (16.14 micro mol per l vs. 14.49 micro mol per l; P less than 0.01) and the lower zinc concentration (17.81 micro mol per l vs. 15.22 micro mol per l;P less than 0.01) was measured in non-ecological system. Significant differences in both microminerals (cooper and zinc) were found among herds. Results of this study confirm variable factors affecting concentration of mineral elements in the blood.