Changes of calcium, phosphorus and magnesium in the blood plasma of holstein mares during gravidity and early lactation

Abstract

High productivity in domestic animals, particularly gravidity, cause an additional metabolic encumbrance. During the gravidity, especially in its end and during the period of lactation, in the process of the change of substances there has been noticed an increased need for minerals both as building elements and the originators of a whole sequence of metabolic systems which are considered the parts of enzymes. The research has been made on six Holstein breed mares aging from 5 to 10 years. During the gravidity and in the early lactation the blood for analysis was taken for three times by venepuncture performed on the jugular vein with heparin as antikoagulant. The blood was taken on three occasions during the gravidity: within the first third of gravidity (till 1 5th week), the second third of gravidity (between 16th and 30th week) and the last trimestar (from 31 st week till a foaling). The last sampling was during early lactation. The blood plasma was separated by centrifugation at 1500g for 15 minutes. The concentration of the minerals in blood plasma has been determined spectrophotometrically with a commercial set. Plasma calcium concentration decreased significantly (p<0,05) during second trimester of the gravidity in comparison with the first and third trimester. But, during the last third of the gravidity the concentration of calcium increased significantly (p<0,05) comparing to the results obtained in the first and fourth period of experiment. The concentration of phosphorus in blood plasma of the mares in the high stage of gravidity and in the beginning of lactation was significantly lower compared with the beginning of the gravidity (p<0,05), while during the second trimester significant increase of concentration was noticed (p<0,05) in comparison to third and fourth trimester. During the first trimester of gravidity, magnesium concentration was significantly higher than those measured at the early lactation period (p<0,05). Comparing to the previous observation, the last trimester was characterized by the significant increase, in consideration of the second and fourth experimental periods (p<0,05). According to the results of research the changes of the concentration of minerals in blood plasma during the period of gravidity and early lactation are closely connected with the metabolic processes which develop during the observation period and with their role in a metabolic process.