Location: Livestock Behavior ResearchTitle: Effect of cooled perches on performance, plumage condition, and foot health of caged White Leghorn hens exposed to cyclic heat
|HU, JIAYING - Purdue University|
|HESTOR, PATRICIA - Purdue University|
|MAKAGON, MAJA - University Of California, Davis|
|XIONG, YIJIE - University Of Illinois|
|GATES, RICHARD - University Of Illinois|
|Cheng, Heng Wei|
Submitted to: Poultry Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/23/2019
Publication Date: 12/11/2019
Citation: Hu, J., Hestor, P.Y., Makagon, M.M., Xiong, Y., Gates, R., Cheng, H. 2019. Effect of cooled perches on performance, plumage condition, and foot health of caged White Leghorn hens exposed to cyclic heat. Poultry Science. https://doi.org/10.3382/ps/pez039.
Interpretive Summary: High environmental temperature is one of the most detrimental problems facing the commercial egg industry, especially during hot summers. In order to alleviate the negative effects of heat stress on laying hens, evaporative cooling methods have been used by some egg companies. However, these methods may increase ambient humidity, which leads to wet manure and litter, overgrowth of bacteria and bad air quality. The objective of this study was to determine if perches in enriched cages could be modified as cooled devices to improve hen performance and physical conditions during cyclic heating episodes. Results showed that the presence of cooled perches improved egg production, egg weight, shell traits, and livability of laying hens without compromising overall plumage conditions and foot health. The results indicate that the cooled perch system could be an effective alternative cooling method for caged laying hen. These results can be used by egg producers to develop management guidelines for improving hen welfare.
Technical Abstract: We examined the effects of water-chilled perches as a cooling device on hen performance during 2 summers using daily cyclic heat. White Leghorns, 17 wk of age, were assigned to 36 cages arranged into 6 banks. The banks were assigned to cooled perches (CP), air perches (AP), and no perches (CTRL) resulting in 2 replicate banks and 12 cages per treatment. Chilled water (10 oC) was circulated through the CP during heat episodes. Daily cyclic heat of 35 oC was applied from 0600 to1800 h with a lowering of temperature to 28 oC from 1800 to 0600 h during the 2014 and 2015 summers when hens were 21 to 35 and 73 to 80 wk of age, respectively. Mortality and egg production were recorded daily. Feed intake, egg weight, and shell quality traits were measured at 4-wk intervals during the heat episodes and at 8-wk intervals during thermoneutrality. Body weight was determined at 17, 35, 72, and 80 wk of age and physical condition; at 80 wk of age. At several age periods during the heat episodes, CP hens had increased egg production (P < 0.0001) and feed usage (P < 0.04) as compared to both AP and CTRL hens. The CP hens had higher BW at 35 and 72 wk of age (P treatment*age = 0.03) and lower cumulative mortality (P = 0.02) than CTRL hens but not AP hens. Eggs from CP hens had overall heavier weights (P < 0.0001) and higher breaking force (P < 0.0001) than eggs from AP and CTRL. Greater eggshell percentage (P treatment*age = 0.03) and eggshell thickness (P treatment*age = 0.01) occurred at some ages during the 2 heat episodes as compared to the other 2 treatments. Nail length, feet hyperkeratosis, and overall feather score were similar among treatments. These results indicate that CP ameliorate the negative effects of heat stress on egg traits and performance without influencing the physical condition of hens.