Journal or Book Title
Research Focus Area(s)
Animal Production Systems Engineering
Heat and moisture production rates (HP, MP) of modern 68- to 75-week-old Hy-Line W-36 laying hens during molting were measured using large-scale indirect calorimeters that mimic commercial production settings. The measurements were performed continuously during acclimation, fasting, restricted feeding, and post-molt. Total HP (THP) was partitioned into latent and sensible HP (LHP, SHP) that incorporated influence of fecal moisture evaporation. THP during fasting (averaging 4.8 W/kg) and restricted feeding (averaging 6.0 W/kg) averaged 29% and 13% lower than that during post-molt (averaging 6.8 W/kg). Correspondingly, LHP averaged 1.9 W/kg and 1.8 W/kg and was 31% and 34%, respectively, lower than that (averaging 2.7 W/kg) during post-molt. Likewise, SHP averaged 2.9 W/kg during fasting and was 28% lower than during post-molt (averaging 4.1 W/kg). The average SHP under restricted feeding and post-molt was similar (4.2 vs. 4.1 W/kg, respectively). Respiratory quotient (RQ) averaged 0.71, 0.76, and 0.92 during fasting, restricted feeding, and post-molt, respectively. Heat production rates during the light period were significantly higher (P < 0.05) than those during the dark period. Daily mean and diurnal LHP as percentages of THP were similar during fasting and post-molt but they were 10% lower during restricted feeding. The results of this study provide a new thermal load database for design of housing ventilation systems for laying hens undergoing molting phase.
Chepete, H. Justin and Xin, Hongwei, "Heat and Moisture Production of Poultry and Their Housing Systems: Molting Hens" (2004). Agricultural and Biosystems Engineering Publications. 206.