Location: Poultry ResearchTitle: Effects of air velocity on laying hen production
|LUCK, B - Mississippi State University|
|DAVIS, J - Mississippi State University|
Submitted to: Proceedings of the American Society of Agricultural and Biological Engineers International (ASABE)
Publication Type: Proceedings
Publication Acceptance Date: 7/15/2013
Publication Date: 8/15/2013
Citation: Purswell, J.L., Branton, S.L., Luck, B.D., Davis, J.D. 2013. Effects of air velocity on laying hen production. Proceedings of the American Society of Agricultural and Biological Engineers International (ASABE). ASABE Paper No. 131620737.
Interpretive Summary: Ventilation is an essential management tool to control the thermal environment in poultry housing and maintain comfort. Increasing air velocity to promote cooling through convection is widely used in meat poultry production to improve performance. The effects of air differing air velocity on laying hen productivity were assessed to determine if similar improvements in performance occurred. Hens under the highest air velocity (300 ft/min) had a hen-day egg production rate of 5.2% and 3.8% greater than those exposed to still air. While feed consumption increased with air velocity, feed conversion ratio and egg weights remained the same. Increased cooling through increased air velocity holds promise for increasing egg production during hot weather by improving thermal comfort and maintaining normal feed consumption rates.
Technical Abstract: Thermal conditions play a major role in production efficiency in commercial poultry production. Mitigation of thermal stress can improve productivity, but must be achieved economically. Weather and system design can limit effectiveness of evaporative cooling and increased air movement has been shown to improve production efficiency in broilers. The objective of this study was to evaluate the effects of increased air velocity on productivity of laying hens by assessing hen-day egg production (HDEP), feed consumption (FC), feed consumption/dozen (FD), feed conversion ratio (FCR), and egg weight (EW). Three treatments were tested (still air, 0.76 m/s, and 1.52 m/s) at 27.8° C and 82% RH to mimic an evaporatively cooled poultry house in the southeastern US under summer weather conditions. Four air velocity test units (wind tunnels) were constructed, each containing cage units which held 10 individual bird cages; still air treatment groups were housed in identical cage units without the surrounding wind tunnel structure. Hens (W-36 breed) were obtained from a commercial laying operation at 23 weeks of age and housed in an adjacent facility until transfer into the wind tunnel units; 48 hens were used in each trial, with eight hens per treatment group. Feed and water were provided ad libitum and the lighting program followed primary breeder recommendations. Eggs were collected and group weighed for each treatment group for 28 days (four one-week periods) and feed consumption was assessed weekly. Three trials were conducted, with two replicate treatment groups per trial, for a total of six replicate treatment groups in the study. Results showed that HDEP for the 1.52 m/s treatment group improved by 5.2% and 3.8% over still air and 0.76 m/s, respectively. Increased FC was observed with increased air velocity, and was significantly different for all treatments. Other measures of performance including EW, FD, and FCR were not different, suggesting that the improvement in HDEP resulted from increased FC. Increased convective cooling may hold promise for increasing egg production rates during hot weather by improving thermal comfort when evaporative cooling is limited by weather or system design.