Prediction of Serum IgG₁ Concentration in Beef Calves Based on Age and Serum Gamma-Glutamyl-Transferase Activity

摘要

This study examined the relationship between serum gamma-glutamyl-transferase (GGT) activity and passive transfer status in beef calves less than 18 days of age. Immunoglobulin G ₁ (IgG ₁ ) concentrations were measured in 69 commercial beef calves between the ages of 24 and 72 hours. GGT activities were then measured in these same calves at various ages between 3 and 18 days of age. Models were developed predicting serum IgG ₁ concentration as a function of calf age and serum GGT activity. Minimal association was present between initial serum IgG ₁ concentration and serum GGT activity when all calves less than 18 days of age were considered ( r ² = 0.065). When the study population was restricted to calves less than 8 days of age, the fit of the developed model was greatly improved ( r ² = 0.438). Serum GGT activity has no apparent advantage relative to other assay procedures for predicting passive transfer status in beef calves. If serum GGT activity is to be used to assess passive transfer status in beef calves, application of this procedure should be restricted to calves less than 8 days of age.