Summary Previous studies have shown that allergy to storage mites is a significant contributor to allergic disease among an isolated farming community in the Orkneys. The present study was undertaken to determine the prevalence of disease due to storage mites among farmers on the mainland of Scotland. Of the 290 subjects employed on 102 randomly selected farms studied, eighty‐seven (30%) reported allergic symptoms on entering barns or byres, and prick tests to storage mites were positive in 62 (21%). Rhinitis and conjunctivitis together were the more frequently reported symptoms, with less than half the subjects recording respitatory symptoms. Specific IgE antibody to storage mites was detected in 43% of subjects reporting allergic symptoms associated with hay dust. Specific IgE to storage mites was strongly associated with atopy in those subjects who reported allergic symptoms.

The concentration of copper in the blood of more than 300 sheep of a grassland flock was determined on each of five occasions between May 1965 and June 1966. Six breed classes, Scottish Blackface, Cheviot and Welsh Mountain, and the three crosses among these breeds, were involved.Breeds differed significantly in blood copper concentration with the Blackface having consistently the lowest and the Welsh the highest values. Crossbred sheep showed marked heterosis. Their levels were mostly at or near to the concentration of the parental breed with the higher value. Within breeds there was a positive regression of blood copper level on live weight of ewe.Ewes which had produced lambs affected by swayback in 1964 had lower levels of copper in their blood than ewes which had produced normal lambs. The difference was significant and most marked in winter.Ewes which were barren had, subsequently, higher blood copper concentrations than ewes with lambs. Ewes with single lambs had on average slightly higher levels than those with twins (but not significantly so), however, the effect differed among the breeds. Blood copper levels differed significantly on most occasions with the week in which ewes lambed in relation to the date of bleeding. Age of ewe had significant effects on copper concentration only at one bleeding (January 1966).There was an indication that classes low in copper concentration, notably Blackfaces and mothers of swayback lambs, showed a relatively steeper decline in copper levels during the winter than did other sheep.to suboptimal performance of animals (for reviews Particular interest in the 'mineral status' of Studies of the mineral status of ruminants in sheep has followed, in recent years, on the intensifi-relation to requirements have revealed remarkably cation of husbandry through feeding, housing and high variation among individual animals (see, for the reclamation and improvement of hill pastures, example, Agricultural Research Council, 1965). Specific metabolic disorders are associated with There is little or no indication, however, whether any excess, deficiency or imbalance of minerals in the of the variability can be attributed to hereditary diet and with variation in the absorption, excretion differences except in relation to a few specific disand retention of minerals by the animals, while orders and to the well established single gene effect effects short of clinical disease may well contribute on the concentration of potassium in the red blood

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Three-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).inbreeding from 0 to 50 %. The animals were born and bred on the farm and managed as one flock The present paper deals with the concentrations since 1955. Five age classes were represented among of a number of minerals in the blood plasma (whole the ewes. Twenty ewes remained in the flock from blood for phosphorus) of sheep in a grassland flock among those which had produced swayback lambs comprising the Scottish

difficulty in the extraction and subsequent steps; take only half as much