Effects of Stocking Density on Steer Performance and Carcass Characteristics in Bedded Hoop and Open Front Confinement Facilities: Progress Report

摘要

Interest in feeding cattle in bedded confinement facilities has grown in part due to increased regulations regarding open feedlot runoff. Work in Iowa has documented that cattle confined in a bedded hoop barn perform similarly to cattle fed in an open feedlot with shelter. The work was done with a stocking density of 50 sq ft per steer in the bedded hoop barn. A hoop barn is a more expensive facility system compared with open lot configurations. Fixed costs (facilities) are partially determined by stocking density. The objective of this study was to determine the effects of increased stocking density on performance and carcass characteristics of steers fed in bedded hoop and bedded open front facilities.The trials were conducted in 2008 and 2009 at the ISU Armstrong Research Farm, Lewis, IA. The hoop barn was stocked with 40, 45, and 50 head per pen resulting in 50, 45, and 40 sq ft per steer, respectively. In the open front cattle feeding facility, pens were constructed to confine the cattle on concrete with bedding. Again the stocking density was 50, 45, and 40 sq ft per steer. In all trials, there was one stocking density per housing type per trial. The diet fed was 45.0% dry corn, 14.8% ground hay, 36.8% modified distillers grains, and 3.4% supplement on an as fed basis. The total diet was approximately 69% dry matter.Because the project is on going, no statistical analysis was performed. However, the cattle performance and carcass characteristics seemed to be similar across all facilities and stocking densities. There may be a trend for slightly less average daily gain for the highest stocking densities (6% less in the hoop and 3% less in the open front). Bunk space may be a factor in cattle performance as well as density. However, without more replications and statistical analysis, no conclusions can be made at this time.