Abstract #T7

# T7
Effects of disbudding on feeding behavior, lying time, and use of a shelter in group-housed calves.
K. Gingerich*1, L. M. Coll-Roman1, E. K. Miller-Cushon1, 1University of Florida, Gainesville, FL.

Disbudding results in behavioral changes indicating a response to pain. We examined the activity, feeding behavior, and shelter use of calves in the 12 h following hot-iron disbudding. Holstein bull and heifer calves (n = 32; 4 calves/pen) were group-housed (7.4 m2/calf) at 16 ± 2 d of age (age range <7 d). Calves were provided milk replacer ad libitum via an automated milk feeder for 6 weeks and gradually weaned over 9 d. All pens had a 3-sided, open top shelter (1.2 × 1.2 m) made out of corrugated plastic. Calves were randomly assigned within pen to be disbudded on different days; half of the calves in each pen were disbudded during wk 5 and the rest were disbudded during wk 6. All calves in the pen were handled in both weeks. Calves received local anesthetic and analgesic before disbudding. Behavior of all calves was recorded continuously from video for 12 h in both weeks, following either disbudding or handling only (control), to characterize lying time and time spent using the shelter (>50% of body inside shelter). Milk intake and feeder visit frequency and duration were summarized for the same 12 h observation period. Data were summarized by week, and analyzed in a general liner model to test effects of treatment (disbudding or control), week, and order of exposure to treatment. Milk intake (8.85 L; SE = 0.45; P = 0.26), visit duration (27.13 min; SE = 2.43; P = 0.62), and visit frequency (4.49 visits/12 h; SE = 0.25; P = 0.23) were not affected by disbudding. Similarly, the frequency (12.4 bouts/12 h; SE = 0.68; P = 0.35) and duration of lying time (483.4 min/12 h; SE = 918.45; P = 0.97) did not differ. Following disbudding, calves entered the shelter more frequently (9.1 vs. 6.4 visits/12 h; SE = 0.81; P = 0.022) but the total duration of time in the shelter was similar (162.9 vs. 87.5 min/12 h; disbudded vs. control; SE = 0.27; P = 0.44). Use of the shelter also changed between weeks, with calves spending more time overall in the shelter during the second observation week (303.3 vs. 48.0 min; SE = 0.27; P = 0.03). These results suggest that the use of a shelter changes around disbudding, and further research is needed to evaluate how added environmental complexity may influence or predict animal welfare.

Key Words: dairy calf, disbudding, behavior