Objective—To evaluate the musculoskeletal analgesic effect of etodolac administered PO every 12 or 24 hours in chronically lame horses by use of force plate analysis.
Animals—22 horses with navicular syndrome.
Procedure—Horses received etodolac (23 mg/kg, PO, q 12 h; n = 7), etodolac (23 mg/kg, PO, q 24 h; 8), or corn syrup (20 mL, PO, q 24 h; control treatment; 7) for 3 days. Combined forelimb peak vertical ground reaction force (PVF) was measured via force plate analysis before the first treatment (baseline) and at 6, 12, 24, and 36 hours after the last treatment. Differences in mean PVF (mPVF) between baseline and subsequent measurements were analyzed (repeated-measures ANOVA) and evaluated for treatment and time effects and treatment-time interaction.
Results—Once- or twice-daily administration of etodolac resulted in significant increases in mPVF from baseline at 6, 12, and 24 hours after the last treatment, compared with the control treatment. There were no significant differences in mPVF between the etodolac treatment groups at any time point. In both etodolac treatment groups, there was a significant increase in mPVF from baseline at 6, 12, and 24 hours, compared with that at 36 hours. Etodolac-associated adverse effects were not detected.
Conclusions and Clinical Relevance—In horses with navicular syndrome, once-daily oral administration of 23 mg of etodolac/kg appears to provide effective analgesia for as long as 24 hours. Twice-daily administration of etodolac at this same dose does not appear to provide any additional analgesic efficacy or duration of effect.
Objective—To use force plate analysis to evaluate the
analgesic efficacies of flunixin meglumine and
phenylbutazone administered IV at typical clinical
doses in horses with navicular syndrome.
Animals—12 horses with navicular syndrome that
were otherwise clinically normal.
Procedure—Horses received flunixin (1.1 mg/kg),
phenylbutazone (4.4 mg/kg), or physiologic saline
(0.9% NaCl; 1 mL/45 kg) solution administered IV
once daily for 4 days with a 14-day washout period
between treatments (3 treatments/horse). Before
beginning treatment (baseline) and 6, 12, 24, and 30
hours after the fourth dose of each treatment, horses
were evaluated by use of the American Association of
Equine Practitioners lameness scoring system (half
scores permitted) and peak vertical force of the forelimbs
was measured via a force plate.
Results—At 6, 12, and 24 hours after the fourth treatment,
subjective lameness evaluations and force
plate data indicated significant improvement in lameness
from baseline values in horses treated with flunixin
or phenylbutazone, compared with control horses;
at those time points, the assessed variables in flunixin-
or phenylbutazone-treated horses were not significantly
Conclusions and Clinical Relevance—In horses
with navicular syndrome treated once daily for 4 days,
typical clinical doses of flunixin and phenylbutazone
resulted in similar significant improvement in lameness
at 6, 12, and 24 hours after the final dose, compared
with findings in horses treated with saline solution.
The effect of flunixin or phenylbutazone was
maintained for at least 24 hours. Flunixin meglumine
and phenylbutazone appear to have similar analgesic
effects in horses with navicular syndrome. (Am J Vet
Objective—To compare anesthetic, analgesic, and cardiorespiratory effects in dogs after IM administration of dexmedetomidine (7.5 μg/kg)–butorphanol (0.15 mg/kg)–tiletamine-zolazepam (3.0 mg/kg; DBTZ) or dexmedetomidine (15.0 μg/kg)-tramadol (3.0 mg/kg)-ketamine (3.0 mg/kg; DTrK) combinations.
Animals—6 healthy adult mixed-breed dogs.
Procedures—Each dog received DBTZ and DTrK in a randomized, crossover-design study with a 5-day interval between treatments. Cardiorespiratory variables and duration and quality of sedation-anesthesia (assessed via auditory stimulation and sedation-anesthesia scoring) and analgesia (assessed via algometry and electrical nerve stimulation) were evaluated at predetermined intervals.
Results—DBTZ or DTrK induced general anesthesia sufficient for endotracheal intubation ≤ 7 minutes after injection. Anesthetic quality and time from drug administration to standing recovery (131.5 vs 109.5 minutes after injection of DBTZ and DTrK, respectively) were similar between treatments. Duration of analgesia was significantly longer with DBTZ treatment, compared with DTrK treatment. Analgesic effects were significantly greater with DBTZ treatment than with DTrK treatment at several time points. Transient hypertension (mean arterial blood pressure > 135 mm Hg), bradycardia (heart rate < 60 beats/min), and hypoxemia (oxygen saturation < 90% via pulse oximetry) were detected during both treatments. Tidal volume decreased significantly from baseline with both treatments and was significantly lower after DBTZ administration, compared with DTrK, at several time points.
Conclusions and Clinical Relevance—DBTZ or DTrK rapidly induced short-term anesthesia and analgesia in healthy dogs. Further research is needed to assess efficacy of these drug combinations for surgical anesthesia. Supplemental 100% oxygen should be provided when DBTZ or DTrK are used.
Objective—To compare analgesic effects of phenylbutazone
administered at a dosage of 4.4 mg/kg/d
(2 mg/lb/d) or 8.8 mg/kg/d (4 mg/lb/d) in horses with
Design—Controlled crossover study.
Animals—9 horses with chronic forelimb lameness.
Procedure—Horses were treated IV with phenylbutazone
(4.4 mg/kg/d or 8.8 mg/kg/d) or saline (0.9%
NaCl) solution once daily for 4 days. All horses
received all 3 treatments with a minimum of 14 days
between treatments. Mean peak vertical force (mPVF)
was measured and clinical lameness scores were
assigned before initiation of each treatment and 6, 12,
and 24 hours after the final dose for each treatment.
Results—Compared with values obtained after
administration of saline solution, mPVF was significantly
increased at all posttreatment evaluation times
when phenylbutazone was administered. Clinical
lameness scores were significantly decreased 6 and
12 hours after administration of the final dose when
phenylbutazone was administered at the low or high
dosage but were significantly decreased 24 hours
after treatment only when phenylbutazone was
administered at the high dosage. No significant differences
in mPVF and clinical lameness scores were
found at any time when phenylbutazone was administered
at the low versus high dosage.
Conclusions and Clinical Relevance—Results suggest
that the high dosage of phenylbutazone was not
associated with greater analgesic effects, in terms of
mPVF or lameness score, than was the low dosage.
Considering that toxicity of phenylbutazone is related
to dosage, the higher dosage may not be beneficial in
chronically lame horses. (J Am Vet Med Assoc 2005;226:414–417)
Objective—To define the pharmacokinetics of florfenicol in synovial fluid (SYNF) and serum from central venous (CV) and digital venous (DV) blood samples following regional IV perfusion (RIVP) of the distal portion of the hind limb in cows.
Animals—6 healthy adult cows.
Procedures—In each cow, IV catheters were placed in the dorsal common digital vein (DCDV) and the plantar vein of the lateral digit, and an indwelling catheter was placed in the metatarsophalangeal joint of the left hind limb. A pneumatic tourniquet was applied to the midmetatarsal region. Florfenicol (2.2 mg/kg) was administered into the DCDV. Samples of DV blood, SYNF, and CV (jugular) blood were collected after 0.25, 0.50, and 0.75 hours, and the tourniquet was removed; additional samples were collected at intervals for 24 hours after infusion. Florfenicol analysis was performed via high-performance liquid chromatography.
Results—In DV blood, CV blood, and SYNF, mean ± SD maximum florfenicol concentration was 714.79 ± 301.93 μg/mL, 5.90 ± 1.37 μg/mL, and 39.19 ± 29.42 μg/mL, respectively; area under the concentration versus time curve was 488.14 ± 272.53 h•μg•mL−1, 23.10 ± 6.91 h•μg•mL−1, and 113.82 ± 54.71 h•μg•mL−1, respectively; and half-life was 4.09 ± 1.93 hours, 4.77 ± 0.67 hours, and 3.81 ± 0.81 hours, respectively.
Conclusions and Clinical Relevance—Following RIVP, high florfenicol concentrations were achieved in DV blood and SYNF, whereas the CV blood concentration remained low. In cattle, RIVP of florfenicol may be useful in the treatment of infectious processes involving the distal portion of limbs.
Objective—To evaluate economic effects and health and performance of the general cattle population after exposure to cattle persistently infected (PI) with bovine viral diarrhea virus (BVDV) in a feedlot.
Animals—21,743 high-risk calves from the southeastern United States.
Procedures—PI status was determined by use of an antigen-capture ELISA (ACE) and confirmed by use of a second ACE, reverse transcriptase–PCR assay of sera, immunohistochemical analysis, and virus isolation from sera. Groups with various amounts of exposure to BVDV PI cattle were used. After being placed in the feedlot, identified PI cattle were removed from 1 section, but PI cattle remained in another section of the feedlot. Exposure groups for cattle lots arriving without PI animals were determined by spatial association to cattle lots, with PI animals remaining or removed from the lot.
Results—15,348 cattle maintained their exposure group. Performance outcomes improved slightly among the 5 exposure groups as the risk for exposure to BVDV PI cattle decreased. Health outcomes had an association with exposure risk that depended on the exposure group. Comparing cattle lots with direct exposure with those without direct exposure revealed significant improvements in all performance outcomes and in first relapse percentage and mortality percentage in the health outcomes. Economic analysis revealed that fatalities accounted for losses of $5.26/animal and performance losses were $88.26/animal.
Conclusions and Clinical Relevance—This study provided evidence that exposure of the general population of feedlot cattle to BVDV PI animals resulted in substantial costs attributable to negative effects on performance and increased fatalities.
OBJECTIVE To determine the effect of dantrolene premedication on various cardiovascular and biochemical variables and recovery in isoflurane-anesthetized horses.
ANIMALS 6 healthy horses.
PROCEDURES Each horse was anesthetized twice with a 21- to 28-day washout period between anesthetic sessions. Food was not withheld from horses before either session. During each session, dantrolene (6 mg/kg in 2 L of water) or water (2 L) was administered via a nasogastric tube 1 hour before anesthesia was induced. Anesthesia was maintained with isoflurane for 90 minutes, during which blood gas analyses and lithium-dilution cardiac output (CO) measurements were obtained every 10 minutes. Serum creatine kinase activity was measured before and at 4, 8, and 12 hours after anesthesia.
RESULTS When horses were premedicated with dantrolene, CO at 25, 35, and 45 minutes after induction of anesthesia was significantly lower than that when horses were premedicated with water after which time difficulty in obtaining valid measurements suggested a continued decrease in CO; plasma potassium concentration progressively increased during anesthesia, whereas serum creatine kinase activity remained fairly stable and within reference limits through 12 hours after anesthesia; and 2 of 6 horses developed cardiac arrhythmias that required medical intervention. The quality of anesthetic recovery was slightly better when horses were premedicated with dantrolene versus water, although the time required for recovery did not differ significantly between treatments.
CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that dantrolene premedication prevented muscle damage without affecting anesthetic recovery but impaired CO and precipitated hyperkalemia and cardiac arrhythmias in healthy isoflurane-anesthetized horses.
Procedure—Calves purchased from an order buyer
were delivered to a feedlot to study the effects of
dietary supplementation with 2,000 IU of vitamin E
for 0, 7, 14, or 28 days after arrival. Serum or plasma
Fib, Hap, SAA, and AGP concentrations were
measured on days 0, 7, and 28 after arrival as well
as at the time of treatment for respiratory tract disease
with antimicrobial drugs and after completion
Results—Vitamin E supplementation was associated
with decreased treatment costs. In cattle that were
not recognized as sick or responded positively to 1
antimicrobial treatment, serum Hap concentrations
were significantly lower on days 0 and 7 than concentrations
for cattle that required > 1 treatment. Serum
Hap concentrations and ratios of Hap to SAA on day 0
significantly correlated with the number of antimicrobial
treatments required. Serum Hap concentrations at
the time of initial treatment were significantly lower
for cattle that required only 1 treatment, compared
with those that required > 1 treatment.
Conclusions and Clinical Relevance—Serum Hap
concentrations are of potential value for use in
assessing feedlot cattle that may become ill as a
result of respiratory tract disease and for use in monitoring
treatment efficacy. (Am J Vet Res 2002;
Objective—To assess changes in muscle glycogen (MG) and triglyceride (MT) concentrations in aerobically conditioned sled dogs during prolonged exercise.
Animals—54 Alaskan sled dogs fed a high-fat diet.
Procedures—48 dogs ran 140-km distances on 4 consecutive days (cumulative distance, up to 560 km); 6 dogs remained as nonexercising control animals. Muscle biopsies were performed immediately after running 140, 420, or 560 km (6 dogs each) and subsequently after feeding and 7 hours of rest. Single muscle biopsies were performed during recovery at 28 hours in 7 dogs that completed 560 km and at 50 and 98 hours in 7 and 6 dogs that completed 510 km, respectively. Tissue samples were analyzed for MG and MT concentrations.
Results—In control dogs, mean ± SD MG and MT concentrations were 375 ± 37 mmol/kg of dry weight (kgDW) and 25.9 ± 10.3 mmol/kgDW, respectively. Compared with control values, MG concentration was lower after dogs completed 140 and 420 km (137 ± 36 mmol/kgDW and 203 ± 30 mmol/kgDW, respectively); MT concentration was lower after dogs completed 140, 420, and 560 km (7.4 ± 5.4 mmol/kgDW; 9.6 ± 6.9 mmol/kgDW, and 6.3 ± 4.9 mmol/kgDW, respectively). Depletion rates during the first run exceeded rates during the final run. Replenishment rates during recovery periods were not different, regardless of distance; only MG concentration at 50 hours was significantly greater than the control value.
Conclusions and Clinical Relevance—Concentration of MG progressively increased in sled dogs undergoing prolonged exercise as a result of attenuated depletion.
To evaluate the effect of 6% hydroxyethyl starch (HES) 670/0.75 and 6% HES 130/0.4 dilution of canine whole blood on coagulation using dynamic viscoelastic coagulometry (DVC).
56 healthy adult dogs.
2 blood samples were obtained from each dog and randomized to 1 of 7 groups—undiluted or 2 dilutions (1:3 or 1:10) of 3 different fluids: saline (0.9% NaCl) solution, 6% HES 670/0.75, or 6% HES 130/0.4. Dilutions were calculated to simulate approximately a 10- or 30-mL/kg body weight IV bolus of each fluid. DVC was performed on each sample. Coagulation parameters compared between groups included clot rate (CR), platelet function (PF), and activated clotting time.
Dilution with saline solution did not significantly affect coagulation, while dilution with HES 670/0.75 and HES 130/0.4 caused a dose-dependent significant decrease in CR (1:3 HES 670/0.75, P = 0.007; 1:10 HES 670/0.75, P = 0.002; 1:3 HES130/0.4, P < 0.0001; and 1:10 HES 130/0.4, P = 0.0003) and PF (1:3 HES 670/0.75, P < 0.0001; 1:10 HES 670/0.75, P < 0.0001; 1:3 HES130/0.4, P < 0.0001; and 1:10 HES 130/0.4, P = 0.0015).
Dilution of canine blood with HES 670/0.75 and HES 130/0.4, at clinically relevant doses (10 and 30 mL/kg), led to significant hypocoagulability beyond dilutional effect. This was, in part, due to impaired PF, which was significantly greater with HES 670/0.75. Further research using DVC to assess the effects of HES on coagulation in dogs, ideally with clinical conditions warranting HES administration, is needed.