Influence of wet and dry feed on laying hens under heat stress.

Two experiments were carried out with a split-plot design over time using White Leghorn hens, 161 days of age. The experiments were conducted to determine the effect of two ambient temperatures (21.1 versus 29.4 C in Experiment 1 and 21.1 versus 33.3 C in Experiment 2) on feed and water consumption using four dietary regimens. The day was divided into two feeding periods: a.m. (0600 to 1300 h) and p.m. (1300 to 0600 h the next morning). The four regimens were as follows: dry feed during both a.m. and p.m. periods; dry feed during a.m. period and wet feed (50% moisture) during the p.m. period; wet feed in the a.m. and dry feed in the p.m.; and wet feet during both a.m. and p.m. periods. The hens were maintained on a 14 h light: 10 h dark lighting program. The hens consumed the greatest quantity of DM and water during the p.m. period, regardless of the environmental temperature to which the hens were exposed. Constant heat stress at 29.4 and 33.3 increased (P less than or equal to .05) drinking water intake during the a.m. but not during the p.m. period. The use of wet feed and dry-wet feed provided a 38 and 48% increase (P less than or equal to .05), respectively, in DM intake when compared with the use of dry feed at 33.3 C. Exposure of laying hens to high environmental temperatures (29.4 and 33.3 C) decreased (P less than or equal to .05) albumen and shell weight; yolk weight was depressed only at 33.3 C. The use of wet feed (50% moisture), ad libitum, or in the p.m. stimulated DM intake at 33.3 C.