|Cheng, Heng Wei|
Submitted to: Poultry Science
Publication Type: Abstract Only
Publication Acceptance Date: 5/7/2004
Publication Date: 6/8/2004
Citation: Gustafson, L., Cheng, H., Pajor, E., Mench, J.A. 2004. Effects of bill-trimming on the welfare of muscovy ducks. Poultry Science. 22:207. Interpretive Summary:
Technical Abstract: Studies have shown that beak-trimmed chickens may show behavioral and physiological indicators of pain post-trim, but there is little information on the effects of bill-trimming on ducks. Muscovy ducks (N=96) were housed in mixed-sex pens containing 16 birds (8 per sex); with three replicate pens per treatment. One half of the birds were trimmed (TRIM) using secateurs at 20 days post-hatch, while the other half were untrimmed controls (CONT). The average length removed from the upper bill was .51cm, or 21.1% of the bill length from nares to tip. Two ducks/sex/treatment were randomly selected as focal birds for behavioral observations, which were conducted immediately post-trim and then at 3-day intervals. The frequency and duration of all behaviors was recorded using 15-min focal animal samples until age 68 days; all birds were weighed weekly. Two observation sessions/pen/week were conducted between 0900-1100 and 1200-1500. In the days immediately post-trim, CON ducks spent 33% of their time performing bill-related behaviors (preening, feeding, drinking, exploratory pecking), whereas TRIM ducks spent only 19% of their time performing such behaviors, a marginally significant difference (p=.063). This difference decreased by one week post-trim (CON 36.5%, TRIM 26.5%; p=0.14). There were no sex differences in behavior. By 4 days post-trim there were no significant (p=0.24) differences in weight between treatments; the average weights of CON and TRIM males were 900g and 640g, respectively, while those of CON and TRIM females were 760g and 720g. By 67 days, the lower bill of TRIM was on average only 11.9% longer than the top bill and there was also evidence of feather pecking, indicating substantial bill re-growth. Our behavioral data suggest that there is probably acute pain associated with trimming, but that it is not sufficiently severe to have marked effects on feed intake. The heads of the focal birds were collected during processing for morphological analysis of the bills. TRIM ducks had scar tissue near the beak stump; bills are currently being examined for evidence of neuromas, which are considered indicators of chronic pain.