Evaluation of the efficacy of novel disbudding methods for dairy calves

The objectives of this study were to: 1) evaluate if cryoablation or the administration of clove oil was as efficacious as cautery disbudding at preventing horn growth and 2) evaluate if the efficacy of cautery disbudding is effected by removing or leaving the horn bud intact after disbudding of dairy calves. At approximately 4 d of age (4.1 ± 0.94 d of age, mean ± SD), 271 dairy heifer calves were enrolled on three dairy farms (farm 1: n = 131 calves; farm 2: n = 113 calves; farm 3: n = 27 calves). Each calf had one of four treatments randomly assigned to each horn bud: 1) clove oil (0.5 mL) administered subcutaneously under the horn bud (CLOV, n = 138 buds); 2) a liquid nitrogen cooled probe applied to the horn bud area for 30 s (CRYO, n = 135 buds; 3) cautery disbudded using an electric hot-iron and the horn bud removed (BUDOFF, n = 134); 4) cautery disbudded and the horn bud tissue left intact (BUDON, n = 135). At approximately 3 and 6 mo of age (first and second check, 3 ± 1.0 mo and 6 ± 2.2 mo respectively, mean ± SD), calves were checked for signs of infection, scur or horn growth. The disbudding procedures were considered successful if no scur or horn development was observed. At the first check, 12% of disbudding wounds showed some indication of infection such as pus, exudate or swelling; of the infected buds, 52% were associated with the BUDON treatment, 27% for CLOV, 25% for BUDOFF and 2% for CRYO treatments. At the second check, BUDOFF was the most effective method of preventing horn growth and CRYO was the least efficacious (mean percentage of successful: BUDOFF: 100% [95% CI; 98.0 – 100.0]; CRYO: 1% [95% CI -0.6 – 3.6]). Injecting clove oil under the horn bud was 87% (95% CI 81.7 – 93.1) successful. Not removing the horn bud tissue after cautery disbudding reduced the efficacy of this method by almost 10% (91% success [95% CI 85.8 – 95.8]), moreover this method was associated with more infection at the site of disbudding. It appears as though the CLOV treatment could be used as an alternative to cautery disbudding of dairy calves, however further research is needed to evaluate the tissue damage caused by clove oil and to refine this technique.