Evaluation of Specific Gravity as a Screening Test for Colostrum

Abstract

The objective of this study was to determine the usefulness of specific gravity (colostrometer) in the field evaluation of colostral quality. Colostrum samples (n=150) were collected during the summer of 1997 from 4 dairies in Fresno County, California. Information gathered on each sample at harvest included dam ID, lactation number, yield in kg, hours since calving, colostrometer reading, color, and subjective assessment of thickness. Samples were frozen for further analysis. A 250 ml sample was thawed and hydrometer readings taken to the nearest 0.0005 units at three different temperatures (0-1 °C in an ice bath, 20 °C in a constant temperature bath, and 37 °C ina constant temperature bath). Each sample was analyzed for IgG using VMRD, Inc SRID Kits.