The concentration of minerals in the blood of genetically diverse groups of sheep: II. Calcium, phosphorus, magnesium, potassium, sodium and chlorine concentrations for three hill-breeds and their crosses at pasture

Abstract

SUMMARYThree-hundred and thirty-four female sheep of the Blackface, Cheviot and Welsh Mountain breeds and the crosses among these breeds kept as one flock at pasture were bled in September 1966. Concentrations of Ca, Mg, K, Na and Cl were determined on plasma and P on whole blood. Mean concentrations (mg/100 ml) were: Ca 9·65; P 5·54; Mg 2·02; K 23·2; Na 345; Cl 365; and coefficients of variation (%) 11·1, 18·1, 29·0, 10·5 6·7 and 2·3 respectively.Breed was a highly significant (P< 0·01) source of variation for Ca, P, Mg and Cl, but except for Mg, the contribution to the total variance was small (< 10 %). Average values for cross-bred ewes deviated significantly (P < 0–05) from those of pure-bred for Ca and P concentration. Live-weight, within class, had a small but significant effect on Ca and Mg concentration.The concentration of Ca and Mg declined very significantly with age of ewe, there was a similar trend for K, while P showed a slight but steady tendency to increase with age, and Cl showed a more erratic increase.For Ca, barren ewes had a lower concentration (– 0·44 mg/100 ml) than ewes with lambs whilst ewes with single lambs at birth had lower concentrations (– 0·35) than ewes with twins. Other factors with effects too large to be ignored (P< 0·1) were the interaction of breed x no. of lambs (K and Cl) and swayback history (Cl).