Location: Livestock Behavior Research2011 Annual Report
1a. Objectives (from AD-416)
The objectives are: 1) to examine the cellular and molecular mechanisms of pain in chickens following beak trimming; 2) to identify if infrared beak trimming is a less painful method than hot blade beak trimming; and 3) to develop pain biomarkers for evaluating husbandry practices used in the farm animal industry.
1b. Approach (from AD-416)
A total of 1,056, 1-day-old, chicks (Hy-line, W-36) will be randomly distributed among 4 treatment groups: infrared beak treatment at 1 day of age; hot-blade trimming at 1 day of age; hot-blade trimming at 7 days of age and; an untrimmed control treatment. The birds will be housed in 6-bird/cage (67 in 2/bird) under the standard management. Mortality will be recorded over the time. Samples (brain, blood, and beak) and behaviors will be collected at 1, 2, 5, 10, 18, 25, 35, 45 and 60 weeks post-trimming (n=12 calculated based an alpha = 0.05 and 1-ß= 0.80). Brain and blood samples will be analyzed for the changes of pain-associated neurotransmitters and neuropeptides using HPLC or RIA, respectively. Beak samples will be analyzed for traumatic-associated changes of nerve fibers and neuroma formation using histological staining, immuncytochemistry, and the microscope imaging system. Both general circadian and pain-test behavior will be recorded using a 16 channel digital video recording (DVR) system. Behavioral data will be collected from using two methods; 5-min scan samples and continuous focal sampling. In addition, physical data, body weight, feather score, feed intake, egg production, and feed efficiency, will be collected in the study. Behavior, neuroendocrine function, and production will be compared statistically among the treatments.
3. Progress Report
The behavioral data, blood, and brain samples from the birds have been collected. The samples are being analyzed in the lab. The current results showed that there were no abnormal nerve fibers within the beak stumps of the hens trimmed at 1 day of age by using infrared or hot blade, which is different from the previous findings collected from the hens trimmed at 5 weeks of age or older. The results also showed that infrared beak trimming is more effective at inhibiting beak re-growth with a less or, at least, a similar impact on hen welfare compared to hot blade beak trimming. One manuscript has been published by a peer-reviewed journal and another one has been submitted.