Agricultural and Biosystems Engineering Publications

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Agricultural and Biosystems Engineering

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Applied Engineering in Agriculture





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A series of six trials involving a total of 1,440 crossbred nursery pigs (6.7–kg initial wt) was conducted at two Iowa State University research farms from December 1999 to August 2000. Three small–scale hoop structures (6.0 . 10.8 m) were divided lengthwise to form two pens (3.0 . 4.5 m) per building for a total of six pens. Six pens (1.7 . 4.0 m) in a mechanically ventilated confinement nursery with slatted floors were used for comparison with the hoop structure pens for each 5–week trial. The hoop pens were equipped with hovers and heat lamps for the winter and spring trials. In each trial, 240 crossbred nursery pigs were weaned at 18 to 22 days old and allotted by weight and litter to one of the six pens found in either the hoop (n = 120) or confinement (n = 120) nursery facility. Four commercial diets were fed in both housing systems in phase for the duration of each trial. During the first 2–week postweaning, the pigs in hoop structures grew 23% slower (P < 0.001) and consumed 23% less feed (P < 0.001) than the pigs in confinement. Both housing systems had similar Average Daily Gain (ADG), Average Daily Feed Intake (ADFI), and Gain:Feed (G:F) for the last 2 weeks of the trial (p > 0.10). As expected, the performance parameters (ADG, ADFI, G:F) were affected by the building and season interaction during each 35–day trial. In all seasons, the hoop pigs’ ADG and ADFI were less than the confinement pigs for the first 2–week postweaning (P < 0.05). During the winter, overall (5 weeks), the pigs in hoop structures grew 5% slower and consumed 9% less feed, but were 5% more efficient converting feed to live weight gain than the pigs in confinement (P < 0.05). In the spring, the pigs in hoop structures grew 7% slower (P < 0.05), consumed 6% less feed (P < 0.05), and had similar feed efficiencies (P > 0.05) as the pigs in confinement during the 5–week trial. During the summer, the pigs in hoop structures grew similarly (P > 0.05), consumed 6% less feed (P < 0.05), and were 8% more efficient (P < 0.05) than the pigs in confinement for the 5–week trial. Bedded hoop structures have not been widely studied as a cold nursery facility during the colder months. The results suggest that older, heavier pigs may perform better when placed directly into a cold facility such as a hoop structure. Further trials with adjustments made to the bedding, heat source, hovers, feeders, and management may improve the growth performance.


Journal Paper No. J-19502 of the Iowa Agriculture and Home Economics Experiment Station, Ames, Iowa, Project No. 3265 and supported by Hatch Act, State of Iowa, and the Leopold Center for Sustainable Agriculture funds. Mention of company or product names is for presentation clarity and does not imply endorsement by the authors or Iowa State University, nor exclusion of any other products that may also be suitable for application.

This article is from Applied Engineering in Agriculture 19, no. 5 (2003): 591–599.



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American Society of Agricultural Engineers



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