Effect of Stress on Serum Zinc and Plasma Corticoid in Dairy Cattle

Abstract

Serum zinc and, in some cases, plasma corticoids were monitored in dairy cattle subjected to six types of stress. Zinc was variable in dairy cattle with normal values ranging from 85 to 175 μg/100 ml and a mean of 117 ± 39 (mean ± standard deviation) for nonstressed controls. Stress increased this variability (133 ± 63) with increased or depressed zinc associated with some stressing condition. Serum zinc did not change significantly in animals injected with corticotropin, and no relationship was observed between plasma corticoids and zinc. Hyperthermal stress had a depressing effect on serum zinc with a negative correlation of –.92 between serum zinc and plasma corticoids. Serum zinc was lower in ketotic cows, higher in cows with evidence of mastitis and in older cows, and showed no change due to routine daily milking. © 1973, American Dairy Science Association. All rights reserved.