|Cheng, Heng Wei|
Submitted to: Poultry Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/2/2007
Publication Date: N/A
Citation: Interpretive Summary: Cannibalism and feather pecking are serious behavioral problems affecting the welfare of commercial poultry. Many factors can contribute to outbreaks of feather pecking and cannibalism in flocks, including light intensity, genetics, group size, lack of foraging opportunities, and nutritional imbalances. Both trimming with cautery and tip-searing were effective in minimizing damage due to feather pecking. However, tip-searing may be a better trimming method than cutting with cautery from the perspective of Pekin duck welfare. Tip-searing did cause behavioral changes indicative of pain for two weeks post-trim, but the decrease in bill-related behaviors was not severe enough to be associated with reduced weight gain during this time, as was seen in the hot blade trimming with cautery ducks. Although neither trimming method led to neuroma formation, tip-searing caused fewer morphological changes in the bills than hot blade trimming with cautery, including less scarring and loss of nerve fibers. Whether this trimming method can be used successfully on duck species such as Muscovy, where there is a longer rearing period and hence the potential for greater bill re-growth, should be investigated. The finding could be adapted by producers and other scientists to develop animal well-being standards and guidelines for management practices.
Technical Abstract: Pekin ducks are often bill-trimmed to prevent feather pecking and cannibalism, but this practice has been criticized because of the resulting potential for acute and chronic pain. The goal of this experiment was to compare two different bill-trimming methods, hot blade trimming with cautery (TRIM) and cautery only (tip-searing; SEAR), on the behavior, bill morphology, and weight gain of Pekin ducks. Ducklings (N = 192, 96 per sex) were trimmed at the hatchery and assigned into 12 floor pens (3.66 m X 0.91 m) by treatment. Behavior was evaluated by scan sampling, and plumage condition scored using a 0 to 3 scoring system. Six ducks were randomly euthanized and the bills collected at 3 and 6 wk of age. Following fixation and decalcification, the bills were embedded in paraffin wax and sectioned longitudinally. Alternate sections were stained with haematoxylin and eosin and Masson’s trichrome for the connective tissues; and Bielschowsky’s silver impregnation, Bodian’s, and Holmes’ staining for the nerve fibers. Trimmed ducks performed fewer bill-related behaviors and rested more than untrimmed ducks (NOTRIM) during the first 2 weeks post-trim. SEAR and NOTRIM showed similar patterns of weight gain, but TRIM had a lower rate of gain than SEAR during the first week post-trim, and than NOTRIM for 2 weeks post-trim. Feather scores of NOTRIM were significantly worse than those of TRIM or SEAR by 18 d, and continued to deteriorate at a greater rate than in trimmed ducks throughout the study. Both trimming methods caused connective tissue proliferation in the bill stumps, but TRIM caused thicker scar tissue than SEAR. No neuromas were found using either trimming method, but there were nerve fibers in the SEAR, but not the TRIM, bill stumps. These results suggest that there is acute pain associated with both trimming methods but that SEAR may be a preferable method, causing less check in weight gain and fewer bill morphological changes while still being effective in minimizing feather pecking damage.