Energy costs of feeding excess protein from corn-based by-products to finishing cattle.

The increased use of by-products in finishing diets for cattle leads to diets that contain greater concentrations of crude protein (CP) and metabolizable protein (MP) than required. The hypothesis was that excess dietary CP and MP would increase maintenance energy requirements because of the energy costs of removing excess N as urea in urine. To evaluate the potential efficiency lost, two experiments were performed to determine the effects of feeding excess CP and MP to calves fed a finishing diet at 1 × maintenance energy intake (Exp.

The effects of implant strategy on finished body weight of beef cattle.

We summarized experimental data to quantify the change in final BW due to a particular implant strategy when cattle are adjusted to the same final body composition. The database developed for this study included 13 implant trials involving a total of 13,640 animals (9,052 steers and 4,588 heifers). Fifteen different implant strategies were used among these trials, including no implant (control), single implants, and combinations of implants.

Predicting individual feed requirements of cattle fed in groups.

A published model designed to predict individual feed required for the observed shrunk BW and ADG of growing cattle when fed in groups was modified and evaluated to improve its accuracy. This model is needed to accurately bill feed and compute cost of gain in marketing programs based on individual animal management. Because of its importance in predicting energy required for growth, a database of 401 steers was used to develop an equation to predict percentage of empty-body fat (EBF) from carcass measurements (12th rib fat thickness, hot carcass weight, USDA quality grade, and longissimus muscle area), which accounted for 61% of the variation in EBF with no bias (P > 0.

Optimization of rate and efficiency of dietary nitrogen utilization through the use of animal by-products and(or) urea and their effects on nutrient digestion in Holstein steers.

The objective of this N balance study was to determine the potential for improving the efficiency and rate of dietary N utilization in Holstein steers by feeding an amino acid-balanced mixture of animal by-product protein sources in combination with urea. The Beef NRC 1996 Model Level 2 was used to formulate a corn-based (86:14 concentrate-hay) control diet with soybean meal as the primary N supplement that would provide ME and metabolizable protein (MP) allowable ADG of 1.4 kg in 250-kg steers with an estrogenic implant and fed an ionophore.

Performance and meat quality of beef steers fed corn-based or bread by-product-based diets.

A feeding trial was conducted with beef breed steers (120) to determine the effects of substituting bread by-product (BBy) for whole shelled corn on performance and meat quality. Chemical analysis of each diet ingredient and in vitro rates of digestion from gas production of BBy and corn were determined to provide accurate information for diet evaluations using the 1996 Beef NRC Model Level 2. Bread by-product contained 16% CP (75.