Effect of blood meal processing method on performance and nitrogen utilization by growing cattle

Abstract

Sixty growing calves averaging 260 kg were used in an 84-day study to evaluate vat-dried and ring-dried blood meal as protein sources for maize-silage-based diets. Protein treatments consisted of: (1) soya bean meal; (2) ring-dried blood meal-urea; (3) vat-dried blood meal-urea. Urea supplied 33% and blood meal 67% of the supplemental crude protein in the blood-meal treatments. Each protein source was fed to provide ration crude protein (CP) levels of either 10.0 or 12.5%. Animals receiving vat-dried blood meal gained less and required more feed per unit of gain, at both protein levels, than calves fed ring-dried blood meal or soya bean meal. Serum urea nitrogen and ruminal ammonia nitrogen concentrations were lower in calves fed vat-dried blood meal compared with those receiving ring-dried blood meal on Day 78 of the study. Average daily gain and feed efficiency were similar for calves fed ring-dried blood meal and soya bean meal. Animals receiving 12.5% CP had higher average daily gains, feed efficiencies, ruminal ammonia and serum urea concentrations than those fed 10.0% CP. Results suggest that vat-dried blood meal was more resistant to microbial degradation in the rumen and also to proteolysis in the small intestine than ring-dried blood meal.