2 Nigerian Dwarf goats (a doe [goat 1] and a wether [goat 2]) with coughing and nasal discharge since they were purchased at an auction 6 days prior were empirically treated for suspected pneumonia and intestinal parasitism. An ivermectin dosing error (intended dose, 0.4 mg/kg, PO; administered dose, 10 mg/kg, PO) was retrospectively discovered, and the owner was urged to return the goats for hospitalization and treatment.
On admission 19 hours after iatrogenic ivermectin overdose, both goats had tachycardia, tachypnea, and absent menace responses. Goat 1 also had vomited in transit, was lethargic and febrile, had slow pupillary light reflexes, and walked into walls and obstacles. Goat 2 was quiet but responsive, not ataxic or febrile, and had pale mucous membranes and a prolonged capillary refill time.
Treatment and Outcome
Each goat received 20% IV lipid emulsion (2 mL/kg, IV bolus over 15 minutes, followed by 0.008 mL/kg/min, IV) and immediately improved. Activated charcoal was administered by orogastric tube, and 6 hours later, mineral oil was similarly administered. Goat 1 had complete resolution of signs and was discharged by 48 and 72 hours, respectively, after admission. Goat 2 improved but developed progressive respiratory distress after the second orogastric intubation and was euthanized. Necropsy findings were consistent with acute renal tubular necrosis, acute respiratory distress syndrome of unknown cause, ruminal tympany, and mesenteric caseous lymphadenitis.
Results indicated that IV lipid emulsion could be used to successfully treat ivermectin toxicosis in goats. Treatment early in the course of ivermectin toxicosis is advisable to avoid severe clinical signs and secondary complications.
Objective—To compare the effects of hetastarch and lactated Ringer's solution (LRS) on plasma colloid osmotic pressure (pCOP) and other hematologic variables in healthy llamas.
Design—Prospective crossover study.
Animals—6 healthy female llamas.
Procedures—Llamas were administered LRS (45 mL/kg [20.5 mL/lb]) and, after a 3-day washout period, hetastarch (15 mL/kg [6.8 mL/lb]) during 60-minute IV infusions. Serum total protein, serum albumin, and hemoglobin concentrations and Hct were measured before each infusion (baseline), immediately after each infusion was completed (0 hours), and at 2, 4, 8, and 12 hours. The pCOP was measured at baseline and at 0, 2, 4, 8, 12, 24, 36, and 48 hours after each infusion was completed; additional measurements of pCOP were obtained 72 and 96 hours after hetastarch infusion.
Results—Hetastarch administration significantly increased mean ± SEM pCOP from 23.5 ± 0.3 mm Hg (baseline) to a peak of 28.4 ± 0.6 mm Hg (12 hours); significant increases in pCOP persisted at 96 hours after hetastarch administration. Administration of LRS significantly decreased albumin and total protein concentrations; in addition, mean ± SEM pCOP decreased from 24.1 ± 0.4 mm Hg (baseline) to 18.0 ± 0.3 mm Hg (0 hours). Hetastarch administration caused more pronounced decreases in Hct (0 hours) and concentrations of hemoglobin (0 hours), albumin (all time points), and total protein (all time points) than did LRS administration.
Conclusions and Clinical Relevance—Hetastarch administration increased pCOP in healthy llamas for 96 hours with no clinically important complications.
OBJECTIVE To compare the effects of equivalent volumes of equine plasma and 6% hydroxyethyl starch (600/0.75) solution (hetastarch) administered IV on plasma colloid osmotic pressure (pCOP) and commonly monitored clinicopathologic variables in horses.
ANIMALS 6 healthy mares.
PROCEDURES In a randomized, crossover study, horses were administered hetastarch or plasma (both 10 mL/kg, IV) 18 months apart. The pCOP and variables of interest were measured before (baseline), immediately after, and at intervals up to 96 or 120 hours after infusion. Prothrombin and activated partial thromboplastin times were measured before and at 2 and 8 hours after each infusion.
RESULTS Prior to hetastarch and plasma infusions, mean ± SEM pCOP was 19.4 ± 0.5 mm Hg and 19.4 ± 0.8 mm Hg, respectively. In general, hetastarch and plasma infusions comparably increased pCOP from baseline for 48 hours, with maximum increases of 2.0 and 2.3 mm Hg, respectively. Mean Hct and hemoglobin, total protein, and albumin concentrations were decreased for a period of 72, 96, or 120 hours after hetastarch infusion with maximum decrements of 8.8%, 3.2 g/dL, 1.2 g/dL, and 0.6 g/dL, respectively. Plasma infusion decreased (albeit not always significantly) hemoglobin concentration and Hct for 20 and 24 hours (maximum changes of 1.5 g/dL and 6.6%, respectively) and increased total solids concentration (maximum change of 0.6 g/dL) for 48 hours. Platelet count and coagulation times were minimally affected.
CONCLUSIONS AND CLINICAL RELEVANCE Overall, the hetastarch and plasma infusions comparably increased pCOP in healthy horses for up to 48 hours. Hetastarch induced greater, more persistent perturbations in clinicopathologic variables.
Objective—To determine serum antibody titers against canine distemper virus (CDV), canine adenovirus type II (CAV-2), and canine parvovirus (CPV) in trained sled dogs prior to and after completion of a long-distance race.
Design—Prospective cohort study.
Animals—195 Alaskan sled dogs (from 18 kennels) that participated in the 2006 Iditarod Trail Race.
Procedures—All 1,323 dogs participating in the race had been vaccinated against the 3 viruses at 19 to 286 days prior to initial blood sample collection (obtained within the month preceding the race). Within 12 hours of race completion, blood samples were collected from 195 dogs (convenience sample) and matched with each dog's prerace sample. Serum antibody titers (90% confidence intervals [CIs]) were determined via serum neutralization assays.
Results—After racing, geometric mean titers against CDV and CPV were significantly higher (2,495 [90% CI, 321 to 16,384] and 6,323 [90% CI, 512 to 32,768], respectively) than prerace values (82 [90% CI, 11 to 362] and 166 [90% CI, 32 to 1,024], respectively). Sixty-one of 194 (31.4%) dogs had t 4-fold increases in anti-CPV antibody titers after racing. Prerace serum antibody titers against CDV, CPV, and CAV-2 varied significantly by sled team but were not associated with time since vaccination.
Conclusions and Clinical Relevance—Postrace increases in serum anti-CDV and anti-CPV antibody titer might reflect exposure of dogs to these agents immediately before or during racing. Dogs had no clinical signs of CDV-, CAV-2-, or CPV-associated disease; therefore, the clinical importance of these titer changes is uncertain.
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.
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.
Objective—To determine the effect of oral administration
of dantrolene sodium on serum creatine
kinase (CK) activity after exercise in horses with
recurrent exertional rhabdomyolysis (RER).
Animals—2 healthy horses and 5 Thoroughbreds
Procedure—3 horses received 2 doses of dantrolene
(4, 6, or 8 mg/kg, PO, with and without withdrawal of
food) 2 days apart; 90 minutes after dosing, plasma
dantrolene concentration was measured spectrofluorometrically.
On the basis of these results, 5
Thoroughbreds with RER from which food was withheld
received dantrolene (4 mg/kg) or an inert treatment
(water [20 mL]) orally 90 minutes before treadmill
exercise (30 minutes, 5 d/wk) during two 3-week
periods. Serum CK activity was determined 4 hours
after exercise. Plasma dantrolene concentration was
measured before and 90 minutes after dosing on the
first and last days of dantrolene treatment and before
dosing on the first day of the inert treatment period.
Results—90 minutes after dosing, mean ± SEM plasma
dantrolene concentration was 0.62 ± 0.13 and 0
µg/mL in the dantrolene and inert treatment groups,
respectively. Serum CK activity was lower in dantrolene-
treated horses (264 ± 13 U/L), compared with
activity in water-treated horses (1,088 ± 264 U/L). Two
horses displayed marked muscle stiffness on the inert
Conclusions and Clinical Relevance—In 5 horses
with RER from which food had been withheld, 4 mg
of dantrolene/kg administered orally provided measurable,
though variable, plasma concentrations and
significantly decreased serum CK activity after exercise
in 4 of those horses. ( Am J Vet Res 2004;
Objective—To determine the effects of SC administration of filgrastim on cell counts in venous blood and bone marrow of healthy adult alpacas.
Animals—10 healthy alpacas.
Procedures—Alpacas were randomly assigned to receive treatment with filgrastim (5 μg/ kg, SC; n = 5) or an equivalent volume of physiologic saline (0.9% NaCl) solution (5) once a day for 3 days. Blood samples were obtained via jugular venipuncture 1 day prior to treatment and once a day for 5 days commencing 24 hours after the first dose was administered. Complete blood counts were performed for each blood sample. Bone marrow aspirates were obtained from the sternum of each alpaca 48 hours before the first treatment was administered and 72 hours after the third treatment was administered. Myeloid-to-erythroid cell (M:E) ratio was determined via cytologic evaluation of bone marrow aspirates.
Results—In filgrastim-treated alpacas, substantial increases in counts of WBCs and neutrophils were detected within 24 hours after the first dose was administered. Band cell count and percentage significantly increased 24 hours after the second dose. Counts of WBCs, neutrophils, and band cells remained high 48 hours after the third dose. Red blood cell counts and PCV were unaffected. The M:E ratio also increased significantly after treatment with filgrastim.
Conclusions and Clinical Relevance—Filgrastim induced rapid and substantial increases in numbers of circulating neutrophils and M:E ratios of bone marrow in healthy alpacas. Therefore, filgrastim may be useful in the treatment of camelids with impaired bone marrow function.
Objective—To determine effects of exercise performed while breathing cold air on expression of cytokines and influx of neutrophils in airways of horses.
Animals—9 adult horses.
Procedures—In a crossover study, bronchoalveolar lavage fluid (BALF) was obtained 24 and 48 hours after each of 2 submaximal exercise sessions performed by horses while breathing warm (25°C) or cold (−5°C) air. Total and differential nucleated cell counts were determined for each BALF sample. Relative mRNA expression of cytokines in BALF cells was quantified by use of a reverse transcription–PCR assay.
Results—Horses had a modest but significant influx of neutrophils into the airways 24 hours after a single exercise session while breathing cold air. No other cell types were increased at 24 or 48 hours after exercising while breathing cold air. Continued increases in expression of cytokines interleukin (IL)-5 and-10 as well as proinflammatory cytokines IL-1, -6, and -8 were detected 24 hours after exercising while breathing cold air. Forty-eight hours after exercising while breathing cold air, expression of IL-10 was still higher than that for IL-10 after horses exercised while breathing warm air. Expression of tumor necrosis factor-α was significantly increased at 48 hours after exercising while breathing cold air.
Conclusions and Clinical Relevance—Exposure of intrapulmonary airways to cold air alters immunologic responses of horses for at least 48 hours. The increased expression of cytokines that suppress cell-mediated immunity may predispose athletes to viral infections of the respiratory tract following exercise in cold weather.
Objective—To determine whether prolonged exercise by conditioned sled dogs affects urine concentrations of homovanillic acid (a metabolite of dopamine), vanillylmandelic acid (a metabolite of norepinephrine and epinephrine), and cortisol.
Animals—24 conditioned Alaskan sled dogs (2 to 8.5 years old) that were in training for a multiday endurance race.
Procedures—Voided urine samples were collected from 4 groups of dogs (randomly selected from 54 dogs) after no exercise (control group; n = 6 dogs), completion of a 160km run (group A; 3), completion of a 420-km run (group B; 7), and completion of a 560-km run (group C; 6). Urine cortisol concentrations were determined by use of an immunoassay technique; urine vanillylmandelic acid and homovanillic acid concentrations were measured via high-performance liquid chromatography.
Results—Compared with the control group, urine cortisol concentration in groups A, B, and C was significantly different (5.33 × 10−4 ± 2.62 × 10−4 μg/dL vs 1.04 × 10−4 ± 2.31 × 10−5 μg/dL, 8.88 × 10−4 ± 5.49 × 10−4 μg/dL, and 6.31 × 10−4 ± 5.09 × 10−4 μg/dL, respectively). Urine homovanillic acid concentration did not differ among the 4 groups. Vanillylmandelic acid was not detected in any urine samples.
Conclusions and Clinical Relevance—Results indicated that prolonged exercise by sled dogs did not affect urine homovanillic acid concentration but did increase urinary cortisol secretion, which is indicative of adrenocortical stimulation. The apparent lack of vanillylmandelic acid in voided urine samples requires further investigation.