Efficacy of caudal epidural injection of lidocaine,xylazine and xylazine
plus hyaluronidase in reducing discomfort produced by electroejaculation in
bulls |
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Authors: | Ronaldo C PAGLIOSA Rafael DEROSSI Deiler S COSTA Fabio JC FARIA |
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Institution: | 1)Department of Animal Reproduction, Faculty of Veterinary Medicine and Animal Science, Federal University of Mato Grosso do Sul, Brazil;2)Department of Veterinary Medicine, Surgery and Anesthesiology, Faculty of Veterinary Medicine and Animal Science, Federal University of Mato Grosso do Sul, Caixa Postal 549, Campo Grande, CEP 79070–900, MS, Brazil |
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Abstract: | To test the hypothesis that epidural administration of lidocaine, xylazine or
xylazine plus hyaluronidase provides reduced pain and stress during electroejaculation in
bulls, eight 30-month-old Nellore bulls received saline solution (control), 2% lidocaine,
2% xylazine or 2% xylazine plus hyaluronidase injected into the first intercoccygeal
(Co1–Co2) epidural space in randomized order. Heart rate, respiratory rate, mean arterial
pressure, analgesia, animal behavior and motor blockade were evaluated before treatment
and at predetermined intervals during and after treatment. Pain and stress were scored
subjectively, and semen quality was evaluated. The onset of anesthetic action was
significantly faster with lidocaine (3.0 ± 1.2 min) than with xylazine or xylazine plus
hyaluronidase (8.9 ± 1.5 and 5.5 ± 2.6 min, P=0.021 and
P=0.012, respectively), and the onset of anesthesia with xylazine plus
hyaluronidase was significantly faster than that with xylazine alone
(P=0.032). Treatment with xylazine or xylazine plus hyaluronidase
resulted in less discomfort than treatment with lidocaine, as indicated by animal
behavior. Changes in heart rate, respiratory rate and arterial pressure were within
acceptable limits. Penile protrusion and semen emission occurred in all animals during all
four treatments. Our results suggest that xylazine plus hyaluronidase reduced discomfort
during electroejaculation more effectively than xylazine or lidocaine alone. Further
experiments are necessary to determine whether electroejaculation with xylazine plus
hyaluronidase is feasible for obtaining semen from Nellore bulls unaccustomed to being
handled or restrained. |
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Keywords: | bull electroejaculation epidural analgesia hyaluronidase xylazine |
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