Variations in serum calcium, inorganic phosphorus and magnesium levels due to stage of lactation, season, and age in Ayrshire cows injected with vitamin D3 prior to calving

Authors

• Vappu Kossila Department of Animal Husbandry, University of Helsinki
• Paavo Niemelä Department of Animal Husbandry, University of Helsinki
• Erkki Koskenkorva Department of Animal Husbandry, University of Helsinki

DOI: https://doi.org/10.23986/afsci.71751

Abstract

Blood mineral studies were carried out in the dairy herd of the Viik Experimental Farm, in which parturient paresis has been successfully prevented by intramuscular injections of vitamin D3 (2 X 5 million I.U.). The material consisted of 41 cows from which 207 blood samples had been taken in 1963 and 12 cows (6 controls, 6 vitamin D injected cows) from which 72 blood samples had been taken in 1969. All cows were either dry and pregnant or lactating and nonpregnant. Compared to values obtained during the dry period, the serum calcium level was only slightly lower shortly after calving. The calcium level increased in the vitamin D treated cows during the ascending phase of lactation, whereas both the calcium and inorganic phosphorus levels remained relatively low in the control cows, respectively. The highest mean magnesium levels occurred during the 2nd and 3rd weeks of lactation. The serum calcium level was higher during the grazing period than during the indoor feeding period. Inorganic phosphorus remained at a relatively high level in younger cows during the grazing period, whereas a significant decrease was noted in the phosphorus level of older cows, respectively. The lowest magnesium values were noted in May, i.e. already before the beginning of the pasture season, the concentration increasing towards the end of the grazing period especially in younger cows. As a whole, younger cows had slightly higher mean serum calcium and magnesium levels and significantly higher inorganic phosphorus levels compared to older cows. The effect of age on the inorg. phosphorus level appeared to be more marked in dry cows and during the grazing period than in lactating cows and during the winter feeding period. Special attention has been paid to the blood mineral values of four individual cows suffering from various illnesses during the study period.