A three-year study of finishing pig performance in hoop structures and confinement buildings was conducted at Iowa State University.

It involved 3,517 pigs for the six trials (three summer and three winter) to compare pig performance. For each trial, three groups of pigs were placed in three (9.1m x 18.3m) hoop structures bedded with cornstalks. The total group equaled 150 pigs. A fourth group (22 pigs per pen) was housed in a mechanically ventilated, confinement building with slatted floors. The pigs began the study weighing 16 kg each and were phase-fed corn/soybean meal diets until they reached 118 kg.

Overall, pigs in the hoop structures had 4.4 percent more backfat, 4.7 percent smaller loineyes and a lower yield than pigs reared in the confinement building. Researchers used 92 kg per pig of bedding in the summer and 112 kg per pig in the winter.

During the summer, pigs in hoop structures ate 3.1 percent more feed, grew 4 percent faster and had 7.4 percent more backfat than the confinement pigs. But pigs in the facilities had similar feed efficiency and loineye size.

During both seasons, pigs in the hoop structures ate more feed. During the winter they used more of the feed energy to maintain body temperature than for growth.

Hoop structure pigs did have a lower mortality rate in the summer (1.8 percent vs. 2.7 percent), but it was higher in the winter (3.8 percent vs. 2.3 percent) compared to confinement-reared pigs.

Cull and lightweight pig losses were similar in the summer (2.5 percent vs. 2.7 percent), but it jumped in the hoop structures during the winter (5.5 percent vs. 2.3 percent). This may be due to larger pig group sizes in hoops, along with a colder environment.

Researchers point out that more information is needed on ways to improve feed efficiency and leanness of pigs raised in hoop structures.