A randomized field study comparing 2 cautery disbudding techniques on wound healing in dairy calves

Disbudding is a routine management practice on dairy farms, and cautery disbudding remains the most popular method in North America. Practitioners commonly employ 2 methods of cautery disbudding: retaining (BUD-IN) or removing (BUD-OUT) the cauterized horn bud. However, comparative evidence regarding healing and pain outcomes between these techniques is limited. The objective of this study was to compare pain sensitivity, wound characteristics, healing outcomes, and growth performance following cautery disbudding with BUD-IN or BUD-OUT in heifer dairy calves. We hypothesized that pain sensitivity and wound healing characteristics would differ between these 2 cautery disbudding methods. A total of 222 healthy female Holstein calves were enrolled at 16 d of age on a commercial dairy farm in New York and randomly assigned to BUD-IN (n = 111) or BUD-OUT (n = 111) treatment groups. All calves received meloxicam (1 mg/kg BW, orally) and a cornual nerve block with 5 mL of 2% lidocaine before disbudding. Wound diameter was the primary outcome variable. Other secondary outcome variables were mechanical nociceptive threshold (MNT), wound discharge, wound healing score, and calf health. All outcome variables were assessed weekly for 8 wk. Body weight was measured at disbudding (wk 0) and 8 wk after disbudding. The continuous outcomes MNT, wound diameter, and ADG were analyzed using generalized linear mixed models; the binary outcome (presence or absence of wound discharge) was analyzed using logistic regression; and time to complete healing was analyzed using Cox proportional hazards regression. Mechanical nociceptive threshold and wound diameter did not differ between groups. Wound discharge was observed during the initial 4 wk post-disbudding. Purulent wound discharge was more common in BUD-IN than BUD-OUT, with an odds ratio (95% CI) of purulent wound discharge in BUD-IN. Time to complete wound healing did not differ between treatments. Average daily gain was not different among groups. Under the conditions of this study, removal of the horn bud during cautery disbudding did not affect pain sensitivity, growth performance, or time to wound healing but was associated with reduced odds of early wound discharge. These findings suggest that both techniques produce comparable long-term outcomes when appropriate analgesia is provided, and the selection of technique may be guided by early wound management considerations.