A Rapid Field Test for the Determination of Colostral Ingestion by Calves, Based on γ-Glutamyltransferase

A qualitative field test for determining the blood level of the enzyme gamma-glutamyltransferase is described for the evaluation of colostral ingestion. The method for enzyme determination is based on dry chemistry technology, and a simple 37 degrees C incubator and colour chart for estimating the activity. There were good correlations between results obtained with the field tests and those obtained with the Reflotron and the wet chemistry conventional methods. Following colostral intake by the calf, blood gamma-glutamyltransferase increased more than 100 fold. There were good correlations between gamma-glutamyltransferase and total globulins in the serum on days 2 and 3 after colostrum intake. Lower but significant correlations were seen between the enzyme and serum total proteins. Good correlation was also seen between the serum enzyme activity and the albumin to globulin ratio. Electrophoretic separation of calf serum showed a significant increase of gamma-globulins after colostral ingestion. The implications and importance of field test are discussed.