Reference intervals and physiological variations of the macro-mineral plasma concentrations in Ouled Djellal ewes

Abstract. This study aimed to establish values and reference intervals of macro-mineral plasma concentrations, as well as the variations of these variables depending on the physiological stages of Ouled Djellal ewes, reared in the Northeast of Algeria. Six plasma macro-mineral elements: calcium (Ca), phosphorus (P), magnesium (Mg), sodium (Na), potassium (K), and chlorine (Cl), were analyzed in blood samples belonging to one hundred thirty-four (n=134) healthy Ouled Djellal ewes (2-5 years old). Obtained levels were statistically analyzed using Reference Value Adviser software in order to establish the reference intervals. In addition, a follow-up study using thirty (30) ewes was carried out to determine the variations of these same parameters depending on the animals’ physiological stages. Animals were subjected to blood sampling during seven periods of their reproductive cycle (dry period; early gestation; mid-gestation; late gestation; early lactation; mid-lactation; after weaning). Reference intervals values for the studied macro elements were: Ca (66-106.7 mgl/L), P (30.5-85 mg/L), Mg (17-32 mg/L), Na (132.6-165 mEq/L), K (3.8-6.2 mEq/L) and Cl (98-123.9 mEq/L). The follow-up study showed significant variations of these macro-elements according to the animal’s reproductive stages. In late gestation, both calcium and magnesium levels increased significantly; however, they showed a significant decrease in early lactation. Phosphatemia was significantly higher in both dry and empty ewes. The lowest values of sodium and potassium were recorded at the beginning of lactation. Chlorine plasma levels decreased very significantly in mid-lactation. Such results provide baseline information that permits monitoring the impact of various mineral disturbances in this breed and checking the animal’s health status depending on its physiological stage.