Evaluation of techniques for lignocaine hydrochloride analgesia of the velvet antler of adult stags |
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| Authors: | PR Wilson KJ Stafford DG Thomas DJ Mellor |
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| Institution: | 1. Institute of Veterinary, Animal and Biomedical Sciences , Massey University , Palmerston North, New Zealand E-mail: P.R. Wilson@massey.ac.nz;2. Hort Research , PO Box 3123, Hamilton, New Zealand;3. Institute of Food, Nutrition and Human Health , Massey University , Palmerston North, New Zealand |
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| Abstract: | Aim: To evaluate the effectiveness of various routes of administration and doses of local anaesthetic (LA) to provide analgesia of the velvet antler of adult stags. Methods: In Experiment 1, antlers from 50 red deer stags, ≥2-years-old were allocated to 1 of 4 treatment groups (n = 25 antlers/group) to receive injections with 2% lignocaine hydrochloride as follows: High-dose (1 ml/cm pedicle circumference) or Low-dose ring-block (0.4 ml/cm pedicle circumference) or; High-site or Low-site regional nerve block (5 ml per site, both of which included the auriculopalpebral nerve). An electrical stimulus was applied before application of LA and then each min for up to 4 min after LA injection. If no response was observed, analgesia was tested with a saw cut. If no response occurred, the antler was cut at that time. If the animal responded, a further wait time was applied until 4 min had elapsed, at which time observations ceased. In Experiment 2, 10 primary and 50 re-growth antlers were given a High-dose ring-block and tested with a saw cut after 1 min (n = 30) or 2 min (n = 30). If no response occurred, the antler was removed. If a response occurred, further 1-min wait periods were applied. Results: In the High-dose ring-block and High-site nerve-block groups, 24/25 and 21/25 antlers were removed without response by 2 min, compared with 20/25 and 15/25 antlers in the Low-dose ring-block and Low-site nerve-block groups, respectively. The High-dose ring-block provided more effective analgesia after 3 min than the Low-dose ringblock, as assessed by the number of stags that did not respond to the electrical stimulus (p = 0.008), or subsequent antler removal (p = 0.050). The numbers of antlers removed without response after 1 or 2 min were greater using the High-site nerve-block than the Low-site nerve-block (p = 0.002 and p = 0.037, respectively). In all but the High-dose ring-block group, at least 1 stag required further LA after 4 min, before antler could be humanely removed. In Experiment 2, stags reacted to a saw-cut test on 6/30 antlers, 1 min after a High-dose ring-block, compared with 1/30 antlers after 2 min (p = 0.051). Conclusion: The High-dose ring-block produced the most effective and rapid analgesia. Clinical relevance: A High-dose ring-block with a 2-min wait period should be the preferred method for achieving local analgesia for velvet antler removal. |
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| Keywords: | Deer velvet antler antler removal local anaesthetic ring block regional nerve block |
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