Effects of chemical restraint on the endoscopic appearance of laryngeal and pharyngeal anatomy and sensation in adult cattle.
Effects of 2 drugs commonly used for chemical restraint of cattle were evaluated for their effect on laryngeal and pharyngeal anatomy, function, and response to stimuli. Eighteen adult Jersey cows, free of respiratory tract disease, were studied. Cows were assigned at random to 1 of 3 treatment groups. Endoscopic evaluations were performed before and at a predetermined time interval after administration of each drug. Responses to stimuli were evaluated by stimulating 7 preselected sites (epiglottis, left and right arytenoid cartilages, left and right vocal folds, and left and right dorsolateral pharyngeal walls) with a closed, transendoscopic biopsy probe. Xylazine HCl (0.05 mg/kg of body weight, i.v.) was administered to group-1 cows (n = 6), and endoscopy was repeated 5 minutes after administration of the drug. Xylazine (0.07 mg/kg, i.v.) was administered to group-2 cows (n = 6), and endoscopy was repeated 5 minutes after administration of the drug. Acepromazine maleate (0.035 mg/kg, i.v.) was administered to group-3 cows (n = 6), and endoscopy was repeated 10 minutes after administration of the drug. Responses to stimuli were scored as brisk (0), moderate (1), slow (2), and absent (3). Scores for responses to stimuli were compared, using the Wilcoxon signed-rank test for data within groups, and a general linear models procedure, using the Kruskal-Wallis test between groups. Interobserver agreement rates were generated for each group. A value of P < 0.05 was considered significant. Xylazine profoundly changed laryngeal sensitivity and function at both dosages. The corniculate processes of the arytenoid cartilages were observed to be in a markedly adducted position after sedation.(ABSTRACT TRUNCATED AT 250 WORDS)
Anderson
D E
DE
Department of Clinical Sciences, College of Veterinary Medicine, Kansas State University, Manhattan 66506-5606.
Gaughan
E M
EM
DeBowes
R M
RM
Lowry
S R
SR
Yvorchuk
K E
KE
St Jean
G
G
D000075:Acepromazine / Q000494:pharmacology*; D000818:Animals; D002417:Cattle / Q000033:anatomy & histology*; D004724:Endoscopy / Q000379:methods / Q000662:veterinary; D005260:Female; D007830:Larynx / Q000033:anatomy & histology* / Q000187:drug effects / Q000502:physiology; D010614:Pharynx / Q000033:anatomy & histology* / Q000187:drug effects / Q000502:physiology; D010812:Physical Stimulation; D012016:Reference Values; D014110:Touch; D014991:Xylazine / Q000494:pharmacology*
D014991:Xylazine; D000075:Acepromazine