THE EFFECT OF PROTEOLYTIC ENZYME AND VITAMIN-MINERAL SUPPLEMENTATION OF A SOY PROTEIN MILK REPLACER ON CALF PERFORMANCE AND NUTRIENT DIGESTIBILITY

Abstract

Fifty-six newborn Holstein bull calves were fed a milk replacer containing 20% of protein from milk sources and 80% of protein from a soy isolate (Promine-F). Eight treatments were designed (seven calves per treatment) in a 4 (enzyme) by 2 (cofactor) experiment to investigate the effect of addition of four levels of proteolytic enzyme (0.0, 1.1, 2.2 or 4.4 million Delft Units (DU) per kilogram of milk replacer) and the presence or absence of a vitamin-mineral supplement (+ or − cofactor). Intake of dry matter from milk replacer or calf starter was not affected by enzyme level or cofactor addition. An increase in the level of enzyme resulted in a reduced rate of gain by calves during the preweaning (4–42 days) and postweaning (42–56 days) periods. Digestibility of dry matter and protein was improved when low levels of enzyme were fed (1.1 and 2.2 million DU/kg) in comparison to when no enzyme or the highest level of enzyme (4.4 million DU/kg) was fed. Addition of the cofactor supplement resulted in an improvement in rate of gain and nutrient digestibilities in comparison to the same ration containing no cofactor.