Behavioural and physiological responses to clove oil injected under the horn bud of calves

{The aim of this study was to evaluate the acute and longer-term behavioural and physiological responses caused by administering clove oil under the horn bud of calves and compare these with the responses caused by cautery disbudding. Forty female Friesian-cross calves (mean +/- SD: 3.5 +/- 2.72 d of age) were allocated to one of four treatments (n = 10 calves/treatment): 1) control handling (CON), 2) administration of 0.5 mL of clove oil under each horn bud (CLOV), 3) cautery disbudding (CAUT) or 4) local anaesthetic plus cautery disbudding (LA + CAUT). Lying behaviour was recorded continuously using accelerometers, while other behaviours were recorded from video for the same 2 h periods on 3 days relative to treatment: baseline (day before), D0 (0-24 h after) and D1 (24-48 h after). Pain sensitivity adjacent to the horn bud was measured using pressure algometry, and blood samples were collected to measure complete blood cell counts and serum amyloid A concentrations, before and 48 h after administration of treatments. CAUT calves tended to perform more head shakes than CON and CLOV calves during the first 2 h after treatment (change from baseline, no./2 h: CON: - 0.3, CAUT: 4.7, LA + CAUT: 3.0, CLOV: - 0.4