Submitted to: Poultry Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 21, 1997
Publication Date: N/A
Interpretive Summary: High temperatures cause broiler deaths. Growth rate and feed conversion are also poorer during high temperatures. Increasing the velocity of ventilation air increases the dissipation of body heat by convection and reduces the need for evaporative heat loss by panting. This research demonstrated that increasing air velocity around the broiler improved growth rate and feed conversion. Reducing the amount of panting increased water consumption from nipple type waterers which also contributed to improved growth and feed conversion. This is the first experimental data to quantify the value of tunnel ventilation of broiler houses.
Technical Abstract: Three trials, using a total of 1320 male broilers, were conducted to study the effect of air velocity at 125 m/min on body weight gain and feed:gain. The broilers were placed on litter in pens in a wind tunnel or on litter in floor pens with conventional cross ventilation when 4 wk old. Except for air velocity, the conditions in both the floor pens and the tunnel were the same. In Trials 1 and 2, only nipple waterers were used. In Trial 3, one half of the pens on the floor and one half of the pens in the tunnel were equipped with open waterers; the remaining pens were equipped with nipple waterers. When compared with conventional ventilation, tunnel rearing improved body weight gain and feed:gain in all three trials. In Trial 3, waterer type did not significantly affect body weight gain or feed:gain in the tunnel. However, body weight gain and feed:gain were reduced in floor reared birds using nipple waterers as compared with birds using open waterers. The increased panting of the conventional ventilated birds, as compared with the tunnel ventilated birds, may have contributed to their decreased body weight gain and improved feed:gain. The improved performance may occur because of the difficulty the birds experience when drinking from nipples while panting.