Evaluation of a carbon dioxide laser scalpel for disbudding Holstein calves: A pilot study

Cautery hot-iron disbudding is a painful routine husbandry practice performed on many dairy farms and calf rearing facilities. Refinements to eliminate or reduce the pain associated with disbudding are desired. Carbon dioxide (CO₂) laser scalpels cut and ablate tissue using high-power light energy. The objective of this study was to test the utility of a CO₂ laser scalpel in bovine disbudding and to compare healing and pain measures with those of cautery hot-iron disbudding. Twelve Holstein bull calves (6-39 d of age) were enrolled in the study. Calves were randomly assigned into groups that were disbudded with a CO₂ laser scalpel (n = 6) or cautery hot iron (n = 6). Calves were sedated with xylazine for the procedure and were given oral meloxicam and a local anesthetic block for analgesia. Outcome measures were maximum surface temperature by infrared thermography, mechanical nociception threshold (MNT) tests, and digital images for wound healing. The infrared thermography and MNT measures were collected before disbudding and out to 72 h postprocedure. Images for wound healing were collected before disbudding and at 6, 24, and 72 h and 7, 14, 28, and 42 d postdisbudding. Overall maximum surface temperatures were not different between groups (35.3 ± 0.3°C vs. 36.0 ± 0.3°C for laser and hot iron, respectively). No differences in overall MNT measures were noted between the laser calves (2.28 ± 0.19) and the hot-iron calves (2.42 ± 0.19 kg of force). All 6 calves in the laser group were completely healed by d 42, whereas only 4 out of 6 hot-iron calves were fully healed. These results suggest that disbudding calves using a CO₂ laser scalpel may be painful based on the outcomes measured. Further research that focuses on pain associated with time points beyond those used in this study and that performs the procedure in unsedated calves is needed to fully evaluate its utility.