EFFECT OF FEEDING SOYBEAN MEAL PROTECTED WITH SODIUM HYDROXIDE, FRESH BLOOD, OR FISH HYDROLYSATE TO GROWING CALVES AND LACTATING DAIRY COWS
Soybean meal (SBM) protected from degradation in the rumen by NaOH, fresh blood (BL) or fish hydrolysate (FH) was evaluated in a digestibility and nitrogen (N) balance trial using weaned male Holstein calves and in a lactation trial (FH was not included) with multiparous high-yielding Holstein cows. N digestibility increased (P < 0.05) by inclusion of NaOH-treated SBM in the diet. N retention by calves increased (P < 0.05) with NaOH or BL treatment. DM intakes and milk composition in the lactation trial were not different across treatments. Milk yield, fat-corrected milk and solids-corrected milk yields and efficiency of protein utilization by cows fed NaOH-treated SBM diet were higher (P < 0.05) than by cows fed untreated SBM diet. These observations suggest that inclusion of NaOH- or BL-treated SBM results in improved protein utilization by young growing calves. NaOH treatment of SBM also results in production of more milk in high-yielding cows during early lactation. Key words: Soybean meal, sodium hydroxide, blood, fish hydrolysate, protected protein, calves, dairy cows