Data from: Wound healing and pain sensitivity following caustic paste disbudding in dairy calves

Caustic paste disbudding is increasing in popularity on commercial dairy
farms in the U.S., but little research has explored the pain and
welfare implications beyond the acute period of this procedure.
Researchers have reported it takes 7 to 9 wk, on average, for hot-iron
disbudding wounds to re-epithelialize in dairy calves. Our objective was
to describe wound healing and sensitivity following caustic paste
disbudding. Jersey and Holstein female calves were disbudded using Dr.
Naylor’s caustic paste at 3 d of age (n = 18) while control calves
received a sham procedure (n = 15). Before disbudding, calves received a
local block and an NSAID. Calves ≥ 34 kg and < 34 kg at birth had
0.3 or 0.25 ml of paste applied per unshaved horn bud, respectively.
Following disbudding, wounds were scored 2x/wk for the presence/absence of
8 tissue categories including the final stages: new epithelium and fully
healed. Control calves were removed from the experiment after 6 wk to be
hot-iron disbudded and avoid more invasive procedures. Mechanical
nociceptive threshold (MNT) measures were collected weekly to evaluate
wound sensitivity until calves were removed from the study or wounds were
healed. Wounds were slow to re-epithelialize (16.2 ± 5.7 wk, mean ± SD;
range: 6.2–32.5 wk) and contract to be considered fully healed (18.8 ± 6
wk, mean ± SD; range: 8.7–34.1 wk). Compared to non-disbudded controls,
paste calves exhibited lower MNT values for all 6 wk (mean ± SE,
Control:1.46 ± 0.16; Paste:1.18 ± 0.12 N). These data indicate that wounds
from caustic paste disbudding are more sensitive than undamaged tissue for
at least 6 wk and take twice as long to heal compared to cautery methods
described in the literature. In conclusion, caustic paste disbudding
wounds took 18.8 wk to fully heal and were more sensitive than intact horn
buds for 6 wk. Future work should examine if aspects of paste application
(e.g., amount, time rubbed in, age, pain mitigation), could improve
healing time and sensitivity.