PREDICTION OF SERUM IGG1 CONCENTRATION IN HOLSTEIN CALVES USING SERUMGAMMA-GLUTAMYLTRANSFERASE ACTIVITY

We examined the relationship between serum gamma glutamyltransferase ( GGT) activity and serum gamma immunoglobulin G (IgG1) concentration in Holstein calves, Blood samples were collected from calves aged 1 to 3 days. A follow-up sample was obtained from each calf 2, 7, or 15 days after the initial sampling. Serum GGT activity acid IgG1 concentratio n were measured. Regression models were used to predict IgG1 concentra tion as a function of age and serum GGT activity measured 2, 7, or 15 days later. Serum GGT activity and calf age at the time of the second sample were directly related to serum IgG1 concentration in the initia l sample in calves aged 3 to 17 days (r = .54) and in calves aged 3 to 10 days (r = .63). Models were used to estimate the serum GGT activit y equivalent to a serum IgG1 concentration of 1,000 mg/dL. One-day-old calves should have serum GGT activities >200 IU/L. Four-day-old calve s should have serum GGT activities >100 IU/L. One-week-old calves shou ld have serum GGT activities >75 IU/L. Carves with serum GGT activitie s <50 IU/L should be classified as having failure of passive transfer. Copyright (C) 1997 by the American College of Veterinary Infernal Med icine.