EFFECTS OF FEEDING CANOLA-MEAL-PROTECTED-TALLOW OR SOYBEAN-MEAL-PROTECTED-TALLOW IN THE LOW-ROUGHAGE DIET OF DAIRY COWS IN EARLY LACTATION

Abstract

Fifteen Holsteins and 12 Ayrshires were randomly assigned within breed and lactation category to one of three isonitrogenous concentrates containing 0% protected tallow (C), 8% soybean-meal-protected-tallow (SPT), or 8% canola-meal-protected-tallow (CPT) which they received during the first 15 wk of lactation. Concentrates and alfalfa hay cubes were offered ad libitum in the ratio 70:30. Statistical analyses compared the effects of diets containing protected tallow (PT) versus the control and secondly the effects of the SPT diet versus the CPT diet. When compared to the control, protected tallow diets significantly increased (P < 0.05) the yields of milk and milk fat and the gross efficiencies of conversion of energy and protein. Plasma NEFA concentration also was significantly higher with PT diets (P < 0.05) than in the control. PT diets significantly reduced milk protein percentage (P < 0.05). There were no significant differences between the SPT and CPT diets for any parameters measured except apparent digestibility of ether extract which was significantly higher for the canola-meal-protected-tallow diet (P < 0.01). Key words: Dairy, cow, milk, composition, protected, lipid, canola