The heritabilities and genetic correlations among eight blood constituents, and their relationship to aspects of performance and genetic polymorphisms, in the sheep

Abstract

ABSTRACTBlood samples were taken from Scottish Blackface ewes of five lines (selected for long and short cannon bones, for hairy and fine fleeces, and an unselected control line) at ages ranging from 9 to 69 months. The samples were analysed for the concentrations of copper, glucose, calcium, magnesium, phosphorus, total protein, albumin and globulin in plasma.The components of variance and covariance between sires and within sires were estimated and heritabilities were calculated for the eight blood constituents and live weight. The heritabilities ranged from 0·20 (s.e. 0·08) for the concentration of copper to 0·43 (s.e. 0·10) for total protein. Only one of the 34 genetic correlations was significantly different from zero, this being between the concentrations of calcium and phosphorus.Ewes that had had a single lamb 9 months earlier had lower concentrations of copper, calcium, albumin (P < 0·001) and glucose (P < 0·01) than ewes that had not lambed. Concentrations of glucose (P < 0·05) and total protein (P < 0·001) were also decreased according to the number of lambs born to the ewe 3 months later.Ewes with low red cell potassium concentrations had higher concentration of glucose in plasma than ewes with high red cell potassium concentrations (P < 0·05). Haemoglobin type affected the concentrations of copper (P < 0·01) and total protein (P < 0·05), with ewes of type B having higher and lower concentrations respectively. The constituents measured were not significantly affected by transferrin type.