Comparison of four semi-quantitative tests for evaluation of colostrum quality in Saanen goats

The aim of this study was to investigate the efficacy of Brix refractometry and to compare the Brix value with semi-quantitative indicators such as total protein (TP), total protein in whey (TPw), glutaraldehyde coagulation time (GCT) and gamma-glutamyl transferase (GGT) enzyme activity for determining the quality of colostrum. Colostrum samples were collected from 38 Saanen goats just after parturition and on the first day (24 ± 4 hours) and second day (48 ± 4) after parturition. The Brix value, TP and TPw levels were measured with optic refractometers. The level of GCT was determined with a 10% glutaraldehyde solution. Immunoglobulin G (IgG) concentrations were measured with a goat IgG ELISA. All measurements decreased significantly after parturition. The IgG and Brix values on the day of parturition were 4719.28 ±107.94 mg/dL and 20.55 ± 0.71, respectively. The TPw levels were lower than TP on all three days and a significant difference was detected on day 2. The IgG concentration was higher in the first-parity and second-parity goats compared with those older does. However, no differences were observed in the other characteristics of the colostrum. Litter size did not affect IgG or the other semi-quantitative tests. Correlation coefficients were higher than 0.8 Tp with TPw, and for the Brix value with both TP and TPw. Brix refractometry could be used to evaluate colostrum quality in Saanen goats and TPw is a more reliable indicator than TP.