Use of a new colostrometer design to predict equine colostral immunoglobulin from specific gravity

The effect of temperature, total milk solids, milk fat, milk lactose, and milk protein on the prediction of colostral immunoglobulin from colostrometer specific gravity readings was studied using a colostrometer with a 15-ml sampling chamber and a radiator bulb hydrometer. Colostral sample results from 30 mares were used to develop an equation to correct specific gravity for variations in water temperature [IgG = (-83000) + (84700 x specific gravity) - (46 x water temperature (°C)]. Although the prediction of immunoglobulin was improved by including milk components, only temperature was included in the equation, since the other parameters are not routinely analyzed in farm situations. The results indicated that the temperature of the colostrometer water column can affect specific gravity readings and that correction for this effect can be made using the developed equation. Colostrum temperature variation within the colostrometer's pycnometer did not have a practical effect on specific gravity readings. The radiator bulb hydrometer did not accurately predict colostral immunoglobulin.