ARF15 - The effects of feeding sorghum co-product from dry mill ethanol production to growing and finishing feedlot cattle

Researcher:

Phil McEwen, University of Guelph, Ridgetown Campus

Objectives:

1. The project will evaluate the effects of feeding corn and sorghum dried distillers grains with solubles (DDGS) on steer growth performance, feed intake, carcass measurements and economic return. The following objectives will be specifically addressed:
   • To determine the effects of feeding corn and sorghum DDGS (20% of DM intake) during a “high forage” growing phase on steer growth, feed intake and economic returns.
   • To determine the effects of feeding corn and sorghum DDGS on lean and fat deposition as assessed by ultrasound (external fat cover, ribeye area, intramuscular fat, etc.) and blood concentrations.
   • To determine the effects of feeding corn and sorghum DDGS on subsequent performance and carcass measurements during the finishing phase.

 

2. The following objectives will be specifically addressed during the “high grain” finishing phase:
   

• To determine the effects of feeding corn and sorghum DDGS  (0 and 20 of ration DM) during the finishing period on steer grow rate, feed intake and efficiency, carcass measurements and economic returns and
  
• To determine the effects of feeding corn and sorghum DDGS on lean and fat deposition, blood (urea N and glucose) and rumen fluid profile (pH and VFA concentration).

Expected Benefits:

Understanding the feeding value of these alternative energy and protein sources will assist both ethanol companies in marketing their products and livestock producers in making decisions on the utilization of alternative feeds.

The project also has the potential of identifying ways to reduce feedlot production costs while increasing the use of sorghum co-product as a feed ingredient.

Summary of Research Results:

Alternate crops will be needed that do not directly compete with corn for acreage to ensure that sufficient grain is available for ethanol production. Sorghum has been successfully grown in the southern United States. The sorghum plant is very adaptable to periods of low moisture and can be grown on a wide range of soil types (heavy clay to light sand). The crop has been successfully grown in Ontario (AERC Inc.) with yields of 85 to 100 bushels per acre recorded. Unfortunately very little research has focused on the feeding value of sorghum co-products for feedlot cattle in Ontario. However in a concurrent project, GreenField Ethanol Inc. was able to contract five hundred acres of sorghum (milo) for distillation during the fall 2007 harvest season. A detailed cost of production summary was completed by four participating farms indicating that the crop was a viable alternative if yields were above 70 bushels per acre.

Adequate levels of corn and sorghum DGSS were supplied by GreenField Ethanol Inc. (in-kind contribution) to complete our feedlot project at the Elora Beef Research Station. The objectives for the project were to determine the effects of feeding corn and sorghum DDGS at 20% of ration DM during "high forage" growing and "high grain" finishing periods on steer growth rate, feed intake and efficiency. The effects of corn and sorghum DDGS feeding on lean and fat deposition was also assessed by ultrasound (external fat cover, ribeye area, intramuscular fat, etc.). Blood urea N and glucose measurements were also taken during both periods to determine if dietary treatment differences were present. After reaching a 10 mm backfat endpoint, steers were slaughtered in the Meat Science Abattoir -University of Guelph with carcass data collected (hot carcass weight, dressing percentage, grade fat, rib eye area and marbling). Carcass rib dissections were also completed to determine dietary differences in lean, bone and fat weight and their rib percentages.