Submitted to: Iowa Cooperative Extension Publication
Publication Type: Proceedings
Publication Acceptance Date: 11/20/2009
Publication Date: 2/11/2010
Citation: Doran, B., Euken, R., Spiehs, M.J. 2010. Hoops and Mono-Slopes: What We Have Learned About Management and Performance. In: Feedlot Forum 2010, Iowa Beef Center at Iowa State University, Dec. 8, 2009 and Feb. 11, 2010, Ames, IA. pp. 8-16. Interpretive Summary:
Technical Abstract: In the past ten years, Iowa beef feedlots have striven to improve environmental management. To reduce the potential for feedlot run-off, there has been increased interest in feeding animals in deep-bedded enclosed facilities. Two types of deep-bedded facilities – hoop barns and mono-slope barns – are now prevalent. A three-year comparison of a bedded hoop barn and an open-front feedlot building was conducted in southwest Iowa. Two groups of yearling steers were fed each year. Summer/fall groups were put on feed in August and marketed in November. Winter/spring groups were put on test feed in December and marketed in April/May. There were no differences for average daily gain, average daily feed intake or feed: gain ratio (P > .05). However, final mud scores (1 = clean; 5 = dirty) were greater (P < .02) for the feedlot cattle compared with the hoop cattle and may have increased the final weight of the feedlot cattle. Yield was lower in the feedlot cattle and may be partly due to differences in the amount of mud on the hide. There were no differences in fat cover, ribeye area, marbling, quality grades, or yield grades by housing type (P > .05). Data were collected from two pens in each of two wide (100 ft) mono-slope barns every 5 to 7 weeks from March 2008 through October 2009. Data were obtained by sampling 56 points in each pen. Volatile solids at 80% were very high compared with levels of 20% for open feedlot manure. Ammonia was collected in acid traps to measure relative differences in ammonia emissions from various areas of the barn and to attempt to understand the factors that influence ammonia emissions. There was no consistent spatial pattern of ammonia emissions. Areas of high ammonia emissions appeared to result from recent urination of cattle. Ammonia emissions decreased rapidly after cattle were removed from pens, reaching an apparent baseline after 4 hours. Ammonia concentration of the manure pack increased as pack and air temperature increased (P < .01). Ammonia emissions were consistently lower in the winter compared to spring /fall and summer (P < .01). Average pack temperature was affected by seasonal change and increased with increasing pack height. Pack height increased as the seasonal temperatures increased. Although the pen averages are less than a foot, there was considerable variation within the pen. Pack height within pens varied from 0 inches to 2.5 feet for the cold and moderate seasons. During the hot season, pack height ranged from 0 inches to 3.63 feet. An informal survey was conducted by Iowa State University Extension beef field specialists; twenty-nine producers across Iowa who fed cattle in either a hoop or mono-slope barn were interviewed to determine their management practices and perceptions about cattle performance. Fifteen of the surveyed producers fed cattle in mono-slope barns; fourteen fed cattle in hoops. About 64% of the mono-slope producers indicated they used more bedding in the winter. Fifty percent of the mono-slope producers noted no change in feed intake. The majority of health problems were respiratory and lameness. However, some pulls for injury were noted. Some deep-bedded producers noted that it was harder to find sick cattle in a deep-bedded facility. In summary, deep-bedded barns can affect cattle performance, cattle comfort, and the environment. However, site-specific management of the barns can enhance or mitigate the magnitude of these effects.