Clove oil delays rather than prevents scur/horn growth in dairy cattle

The objective of this study was to evaluate if administration of clove oil prevents horn growth in dairy cattle long term. At approximately 4 d of age, calves had one of four treatments assigned to each horn bud: 1) cautery disbudded and the horn bud removed (BUDOFF, n=126); 2) cautery disbudded and the horn bud tissue left intact (BUDON, n=129); 3) a liquid nitrogen filled probe applied to the horn bud area (CRYO, n=131) buds; 4) clove oil administered subcutaneously under the horn bud (CLOV, n=132 buds). At approximately 16 months of age, all cattle were checked for scur or horn development. A sub-set of scurs/horns from the CLOV cattle were removed to evaluate tissue and structural development. Cautery disbudding prevented horn development in all cattle, but scurs were observed in 2% of BUDON cattle. CRYO resulted in 76% and 24% of buds developing into horns or scurs respectively. 5% of CLOV buds developed into horns and 63% into scurs; 9% of the scurs looked like normally developed horns but they were not attached to the skull. Injecting clove oil under the horn bud appeared to delay horn development not prevent it.