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  • Author or Editor: Neil H. Willits x
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Abstract

Objective—To develop an objective, accurate method for quantifying forelimb ground reaction forces in horses by adapting a human in-shoe pressure measurement system and determine the reliability of the system for shod and unshod horses.

Animals—6 adult Thoroughbreds.

Procedure—Horses were instrumented with a human in-shoe pressure measurement system and evaluated at a trot (3 m/s) on a motorized treadmill. Maximum force, stance time, and peak contact area were evaluated for shod and unshod horses. Three trials were performed for shod and unshod horses, and differences in the measured values were examined with a mixed model ANOVA for repeated measures. Sensor accuracy was evaluated by correlating measured variables to clinically observed lameness and by a variance component analysis.

Results—4 of 6 horses were determined to be lame in a forelimb on the basis of clinical examination and measured values from the system. No significant differences were observed between shod and unshod horses for maximum force and stance time. A significant decrease in peak contact area was observed for shod and unshod horses at each successive trial. Maximum force measurements provided the highest correlation for detecting lameness ( r = 0.91, shod horses; r = 1.0, unshod horses). A variance component analysis revealed that 3 trials provided a variance of 35.35 kg for maximum force (± 5.78% accuracy), 0.007 seconds for stance time (± 2.5% accuracy), and 8.58 cm2 for peak contact area (± 11.95% accuracy).

Conclusions and Clinical Relevance—The in-shoe pressure measurement system provides an accurate, objective, and effective method to evaluate lameness in horses. ( Am J Vet Res 2001;62:23–28)

Full access
in American Journal of Veterinary Research

Abstract

Objective—To evaluate the thermal antinociceptive and sedative effects and duration of action of tramadol hydrochloride after oral administration to American kestrels (Falco sparverius).

Animals—12 healthy 3-year-old American kestrels.

Procedures—Tramadol (5, 15, and 30 mg/kg) and a control suspension were administered orally in a masked randomized crossover experimental design. Foot withdrawal response to a thermal stimulus was determined 1 hour before (baseline) and 0.5, 1.5, 3, 6, and 9 hours after treatment. Agitation-sedation scores were determined 3 to 5 minutes before each thermal stimulus test.

Results—The lowest dose of tramadol evaluated (5 mg/kg) significantly increased the thermal foot withdrawal thresholds for up to 1.5 hours after administration, compared with control treatment values, and for up to 9 hours after administration, compared with baseline values. Tramadol at doses of 15 and 30 mg/kg significantly increased thermal thresholds at 0.5 hours after administration, compared with control treatment values, and up to 3 hours after administration, compared with baseline values. No significant differences in agitation-sedation scores were detected between tramadol and control treatments.

Conclusions and Clinical Relevance—Results indicated oral administration of 5 mg of tramadol/kg significantly increased thermal nociception thresholds for kestrels for 1.5 hours, compared with a control treatment, and 9 hours, compared with baseline values; higher doses resulted in less pronounced antinociceptive effects. Additional studies with other types of stimulation, formulations, dosages, routes of administration, and testing times would be needed to fully evaluate the analgesic and adverse effects of tramadol in kestrels and other avian species.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To evaluate the antinociceptive and sedative effects and duration of action of hydromorphone hydrochloride after IM administration to American kestrels (Falco sparverius).

Animals—11 healthy 2-year-old American kestrels.

Procedures—Hydromorphone (0.1, 0.3, and 0.6 mg/kg) and an equivalent volume of saline (0.9% NaCl) solution (control treatment) were administered IM to kestrels in a masked randomized complete crossover study design. Foot withdrawal response to a thermal stimulus was determined 30 to 60 minutes before (baseline) and 0.5, 1.5, 3, and 6 hours after treatment administration. Agitation-sedation scores were determined 3 to 5 minutes before each thermal test.

Results—Hydromorphone at 0.6 mg/kg, IM, significantly increased the thermal foot withdrawal threshold, compared with the response after administration of saline solution, for up to 3 hours, and hydromorphone at 0.1, 0.3, and 0.6 mg/kg, IM, significantly increased withdrawal responses for up to 6 hours, compared with baseline values. No significant differences in mean sedation-agitation scores were detected between hydromorphone and saline solution treatments; however, appreciable sedation was detected in 4 birds when administered 0.6 mg of hydromorphone/kg.

Conclusions and Clinical Relevance—Hydromorphone at the doses evaluated significantly increased the thermal nociception threshold for American kestrels for 3 to 6 hours. Additional studies with other types of stimulation, formulations, dosages, routes of administration, and testing times are needed to fully evaluate the analgesic and adverse effects of hydromorphone in kestrels and other avian species and the use of hydromorphone in clinical settings.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To evaluate antinociceptive effects and pharmacokinetics of butorphanol tartrate after IM administration to American kestrels (Falco sparverius).

Animals—Fifteen 2- to 3-year-old American kestrels (6 males and 9 females).

Procedures—Butorphanol (1, 3, and 6 mg/kg) and saline (0.9% NaCl) solution were administered IM to birds in a crossover experimental design. Agitation-sedation scores and foot withdrawal response to a thermal stimulus were determined 30 to 60 minutes before (baseline) and 0.5, 1.5, 3, and 6 hours after treatment. For the pharmacokinetic analysis, butorphanol (6 mg/kg, IM) was administered in the pectoral muscles of each of 12 birds.

Results—In male kestrels, butorphanol did not significantly increase thermal thresholds for foot withdrawal, compared with results for saline solution administration. However, at 1.5 hours after administration of 6 mg of butorphanol/kg, the thermal threshold was significantly decreased, compared with the baseline value. Foot withdrawal threshold for female kestrels after butorphanol administration did not differ significantly from that after saline solution administration. However, compared with the baseline value, withdrawal threshold was significantly increased for 1 mg/kg at 0.5 and 6 hours, 3 mg/kg at 6 hours, and 6 mg/kg at 3 hours. There were no significant differences in mean sedation-agitation scores, except for males at 1.5 hours after administration of 6 mg/kg.

Conclusion and Clinical Relevance—Butorphanol did not cause thermal antinociception suggestive of analgesia in American kestrels. Sex-dependent responses were identified. Further studies are needed to evaluate the analgesic effects of butorphanol in raptors.

Full access
in American Journal of Veterinary Research