Dose-dependent antinociceptive and sedative effects of epidural romifidine in cattle.

The objective of this study was to evaluate the antinociceptive and sedative effects of epidural administration of romifidine in dairy cattle. Twenty-four dairy cows, divided randomly into four groups (three experimental and one control; n=6) received one of three doses of romifidine (30, 40 or 50 μg/kg) diluted in sterile saline (0.9 per cent) to a final volume of 25 ml or an equivalent volume of sterile saline. Antinociception and its anatomical extent was assessed by applying a standard stimulus (needle pin pricks) in different areas and by applying an electrical stimulus to the flank. The antinociceptive effect of romifidine was produced not only in the tail, anus, perineum, vulva and inguinal area but extended up to the coronary band of the hindlimbs and chest areas. Epidural romifidine induced mild-to-moderate sedation at 30 and 40 μg/kg doses and deep sedation at the 50 μg/kg dose. The antinociceptive and sedative effect was dose-dependent in terms of intensity and duration. Thus, epidural administration of romifidine was effective in providing antinociception and sedation in cattle, and can be used in standing flank and udder surgery in cattle.