title: Live performance of male broilers subjected to constant or increasing air velocities at moderate temperatures with a high dew point.
abstract: This study examined the effects of varying air velocities vs. a constant air velocity with a cyclic temperature curve of 25-30-25 degrees C and a dew point of 23 degrees C on broilers from 28 to 49 d of age. Four replicate trials were conducted. In each trial, 742 male broilers were randomly allocated to 6 floor pens or 2 air velocity tunnels, with each tunnel consisting of 4 pens. Bird density, feeder, and waterer space were similar across all pens (53 birds/ pen; 0.07 m2/bird). The treatments were control (still air), constant air velocity of 120 m/min, and increasing air velocity (90 m/min from 28 to 35 d, 120 m/min from 36 to 42 d, and 180 m/min from 43 to 49 d). Birds grown in a still air environment gained less weight, consumed less feed, and converted feed less efficiently between 28 and 49 d than birds subjected to moving air (constant or increasing). Growth responses between the air velocity treatments were similar from 28 to 35 and 36 to 42 d of age. Increasing air velocity to 180 m/min improved (P < or = 0.02) the growth rate of broilers from 43 to 49 d of age over birds receiving an air velocity of 120 m/min, but the incidence of mortality was not affected. These results provide evidence that increasing air velocity from 120 to 180 m/min is beneficial to broilers weighing 2.5 kg or greater when exposed to moderate temperatures.
authors.affiliation: USDA/ARS, Poultry Research Unit, Mississippi State, Mississippi 39762, USA. bdozier@msa-msstate.ars.usda.gov
authors.forename: W A
authors.initials: WA
authors.lastname: Dozier
authors.forename: B D
authors.initials: BD
authors.lastname: Lott
authors.forename: S L
authors.initials: SL
authors.lastname: Branton
mesh_terms: D000392:Air Movements; D000818:Animals; D001833:Body Temperature Regulation; D002645:Chickens / Q000254:growth & development*; D005247:Feeding Behavior; D006799:Housing, Animal; D006813:Humidity; D008297:Male; D013696:Temperature; D015430:Weight Gain