Submitted to: Poultry Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/19/2002
Publication Date: 10/20/2003
Citation: Simmons, J.D., Miles, D.M., Lott, B.D. 2003. The effects of high air velocity on broiler performance. Poultry Science. 82:232-234. Interpretive Summary: Very few broiler houses are built today without tunnel ventilation. The most desired feature of this ventilation scheme is the benefit of higher air velocity over the broilers, but the actual benefit from a production standpoint remains ambiguous. This is due in part because an optimal air speed (for increased production) exists for each ambient condition and each size (and thus age) broiler. To continually employ the proper air velocity during the final weeks of rearing, the relationship between production and the actual air velocity is imperative. The purpose of this research was to determine the effects of high air velocity on growth and feed conversion of broilers at normal tunnel-ventilation temperatures. Results demonstrated that air velocities of 180 and 120 (mpm) had no significant effect on body weight gain or feed conversion during the first week of rearing (week 3-4) as compared with still air. However, during the mid weeks of rearing (weeks 4-5 and 5-6), significant improvements were noted in body weight gains and feed conversion for these increased velocities. Further, during the last week of rearing (week 6-7), an air velocity of 180 mpm significantly improved body weight gains and feed conversion as compared with 120 mpm or still air. Growers will immediately use this information to adjust the tunnel ventilation air velocity to their best advantage during the final weeks of rearing.
Technical Abstract: Two trials, using a total of 1,484 male broilers, were conducted to study the effect of air velocities of 180 and 120 m/min (mpm) versus still air (<15 mpm) on body weight gain and feed:gain. Broilers were raised in a common environment to 3 wk of age. At 3 wk of age, 53 birds were placed in pens on litter in each of two wind tunnels (4 pens/tunnel) or on litter in floor pens (6 pens) in an environmentally controlled facility. The temperature regimen was a diurnal cycle of 25-30-25 C with 23 C dewpoint. Air velocities of 180 and 120 mpm had no significant effect on body weight gain or feed:gain during the first week (3-4 wk) in the tunnels as compared with the still air. However, during the 4-5 and 5-6 week periods, significant improvements were noted in body weight gains and feed:gains for increased air velocities. During the last week (6-7), an air velocity of 180 mpm significantly improved body weight gain and feed:gain as compared with the 120 mpm or the still air.