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Summary

Tear production, evaluated every 2 hours from 8 am to 8 pm by use of the Schirmer tear test over a 3-day period, was not significantly different between left and right eyes in 12 dogs. However, a significant diurnal pattern was evident. Tear production was lowest at midday and highest in the late afternoon/early evening. After pilocarpine HCl ophthalmic solution (0.25, 1.0, or 2.0%; 1 drop) was administered topically to the left eye of each dog at 7 am on days 4, 6, and 8, respectively, tear production was determined for both eyes every 2 hours from 8 am to 8 pm on the day of treatment. Analysis of tear values between eyes and between each eye’s treatment and pretreatment values did not reveal significant change for the treated eye, but tear production was significantly less in the untreated eye, compared with its pretreatment values and with values in the treated eye. On day 10 (48 hours after the last treatment), tear production values were not significantly different between left and right eyes, and for both eyes, were not significantly different from the mean pretreatment tear production values. Topical application of 0.25, 1.0, or 2.0% pilocarpine HCl consistently caused blepharospasm, conjunctival hyperemia, and miosis of the treated eye, without significant increase in tear production. We concluded that topical application of pilocarpine, at the concentrations used, may have little value in treating disorders involving reduced tear production.

Free access
in Journal of the American Veterinary Medical Association

Summary

Cardiorespiratory effects of an iv administered bolus of ketamine (7.5 mg/kg of body weight) and midazolam (0.375 mg/kg) followed by iv infusion of ketamine (200 μg/kg/min) and midazolam (10 μg/kg/min) for 60 minutes was determined in 6 dogs. Ketamine-midazolam combination was administered to dogs on 3 occasions to determine effects of prior administration of iv administered saline solution (1 ml), butorphanol (0.2 mg/kg), or oxymorphone (0.1 mg/kg). The infusion rate of ketamine and midazolam was decreased by 25% for anesthetic maintenance after opioid administration.

There were no significant differences in cardiorespiratory variables after saline solution or butorphanol administration; however, oxymorphone caused significant (P < 0.05) increases in mean arterial blood pressure, systemic vascular resistance, and breathing rate. Bolus administration of ketamine-midazolam combination after saline solution caused significant (P < 0.05) increases in heart rate, mean arterial blood pressure, cardiac index, mean pulmonary blood pressure, venous admixture, and significant decreases in stroke index, pulmonary capillary wedge pressure, arterial and mixed venous oxygen tension, arterial oxygen content, and alveolar-arterial oxygen gradient. Opioid administration was associated with significantly (P < 0.05) lower values than was saline administration for heart rate, mean arterial blood pressure, and arterial and mixed venous pH and with higher values for stroke index, pulmonary capillary wedge pressure, and arterial and mixed venous carbon dioxide tension. Prior oxymorphone administration resulted in the highest (P < 0.05) values for mean pulmonary blood pressure, venous admixture, and arterial and mixed venous carbon dioxide tension, and the lowest values for arterial oxygen tension, and arterial and mixed venous pH. Each treatment provided otherwise uncomplicated anesthetic induction, maintenance, and recovery. Time to extubation, sternal recumbency, and walking with minimal ataxia was similar for each treatment.

Free access
in American Journal of Veterinary Research

Abstract

OBJECTIVE To test a unique electronic ear tag designed to collect movement data to determine whether physical activity of sick steers differed from that of healthy steers.

ANIMALS 206 steers.

PROCEDURES Physical activity in 2 groups of steers during November and December of 2010 (101 steers; the tag of 1 steer failed, and thus that steer was removed from the study, which resulted in data for 100 steers) and 2011 (105 steers) was monitored with an electronic ear tag device with an on-board triple-axis accelerometer. The accelerometer recorded motion in all 3 axes in the form of counts per minute. A radio-frequency transmitter on the ear tag delivered serial packets of motion data to a local server. An algorithm was developed to analyze the activity data to determine whether this technique could be used to assess health status with high accuracy.

RESULTS Steers that became sick had significantly fewer activity counts (approx 25% fewer), compared with the activity counts of steers that remained healthy the entire time.

CONCLUSIONS AND CLINICAL RELEVANCE In this study, automated detection of health status in growing cattle was feasible through remote monitoring of animal activity. Early identification of sick animals should lead to improved health outcomes, increased marketability, and improved animal well-being and help to minimize the use of antimicrobials that could contribute to resistant bacteria.

Full access
in American Journal of Veterinary Research

Abstract

Case Description—3 adult (24- to 43-year-old) Atlantic bottlenose dolphins (Tursiops truncatus) with chronic episodic malaise and inappetence associated with high serum aminotransferase (alanine aminotransferase and aspartate aminotransferase) activities, high serum iron concentration, and serum transferrin saturation > 80% were evaluated.

Clinical Findings—Results of histologic examination of liver biopsy specimens revealed hemosiderosis in all 3 dolphins. Except for chronic lymphocytosis in 1 dolphin, results of extensive diagnostic testing revealed no other abnormalities. For each dolphin, a diagnosis of iron overload of unknown origin was made.

Treatment and Outcome—Phlebotomy treatment was implemented to reduce body stores of iron. Each phlebotomy procedure removed 7% to 17% (1 to 3 L) of estimated blood volume. Treatment consisted of an induction phase of weekly phlebotomy procedures for 22 to 30 weeks, which was complete when serum iron concentration and aminotransferase activities were within reference ranges and serum transferrin saturation was ≤ 20% or Hct was ≤ 30%. Total amount of iron removed from each dolphin was 53 to 111 mg/kg (24.1 to 50.5 mg/lb) of body weight. One dolphin required maintenance procedures at 8- to 12-week intervals when high serum iron concentration was detected.

Clinical Relevance—Although the cause of the iron overload and high serum aminotransferase activities remained unknown, phlebotomy treatment successfully resolved the clinicopathologic abnormalities, supporting a role of iron overload in the hepatopathy of the 3 dolphins.

Full access
in Journal of the American Veterinary Medical Association

Abstract

Objective—To evaluate annual survival and mortality rates and the longevity of a managed population of bottlenose dolphins (Tursiops truncatus).

Design—Retrospective cohort study.

Animals—103 bottlenose dolphins at the US Navy Marine Mammal Program (MMP).

Procedures—Population age structures, annual survival and crude mortality rates, and median age at death for dolphins > 30 days old were determined from 2004 through 2013.

Results—During 2004 through 2013, the annual survival rates for MMP dolphins ranged from 0.98 to 1.0, and the annual crude mortality rates ranged from 0% to 5%, with a mean of 2.7%. The median age at death was 30.1 years from 2004 through 2008 and increased to 32 years from 2009 through 2013. The maximum age for a dolphin in the study was 52 years.

Conclusions and Clinical Relevance—Results indicated that the annual mortality rates were low and survival rates were high for dolphins in the MMP from 2004 through 2013 and that the median age at death for MMP dolphins during that time was over 10 years greater than that reported in free-ranging dolphins. These findings were likely attributable to the continually improving care and husbandry of managed dolphin populations.

Full access
in Journal of the American Veterinary Medical Association

Objective

To examine the effects of limited food intake on frequency and severity of osteoarthritis in coxofemoral joints of Labrador Retrievers.

Design

Dogs were paired according to gender and body weight, within each litter, at 8 weeks of age. One dog of each pair was fed ad libitum. The limit-fed pairmate was fed 75% of the amount eaten the previous day by the ad libitum-fed counterpart.

Animals

48 Labrador Retrievers.

Procedure

All dogs received the same diet. Radiographic evaluation of coxofemoral joints for frequency and severity of osteoarthritis were made when dogs were 4 and 6 months and 1, 2, 3, and 5 years old.

Results

Radiographic evaluation for osteoarthritis indicated greater frequency and more severity of osteoarthritis in the ad libitum-fed group of dogs.

Clinical Implications

Analysis of data suggested that limit feeding of dogs over a 5-year period minimizes development of osteoarthritis in the coxofemoral joints.

Free access
in Journal of the American Veterinary Medical Association

Summary

Cardiopulmonary consequences of iv administered glycopyrrolate (0.01 mg/kg of body weight), followed in 11 ± 2 minutes by butorphanol (0.2 mg/ kg) and xylazine (0.5 mg/kg), were evaluated in 6 dogs, with and without nasal administration of oxygen (100 ml/kg/min). Glycopyrrolate caused significant (P < 0.05) increases in heart rate and cardiac index and significant (P < 0.05) decreases in stroke index.

Subsequent administration of butorphanol and xylazine was associated with significant (P < 0.05) increases in systemic vascular resistance, mean arterial blood pressure, mean pulmonary artery pressure, central venous pressure, pulmonary capillary wedge pressure, PaCO2 , venous admixture, oxygen extraction ratio, and hemoglobin concentration. It caused significant (P < 0.05) decreases in cardiac index, stroke index, breathing rate, minute volume index, oxygen delivery, and oxygen consumption. Mean arterial blood pressure, pulmonary vascular resistance, tidal volume index, and minute volume index were significantly (P < 0.05) higher when dogs were breathing room air. The arterial and venous PO2 and PCO2 , and venous oxygen content were significantly (P < 0.05) higher, and the arterial and venous pH, and oxygen consumption were significantly (P < 0.05) lower when oxygen was administered. Pulsus alternans and S-T segment depression were observed in dogs of both groups. Ventricular premature contractions were observed in 1 dog breathing room air.

All dogs were intubated briefly 15 minutes after administration of butorphanol and xylazine. Time to first spontaneous movement was 45 minutes. All dogs remained in lateral recumbency without physical restraint for 60 minutes.

Free access
in American Journal of Veterinary Research

Abstract

Objective—To compare ground reaction forces (GRFs) measured by use of a pressure-sensitive walk-way (PSW) and a force plate (FP) and evaluate weekly variation in the GRFs and static vertical forces in dogs.

Animals—34 clinically normal dogs and 5 research dogs with lameness.

Procedure—GRF data were collected from 5 lame and 14 clinically normal dogs by use of an FP and a PSW. Peak vertical force (PVF), vertical impulse (VI), and velocity measurements (determined by use of photocells and PSW data) were compared between groups. Peak vertical force, VI, stride length, ground phase time (ie, contact time), and static body weight distribution data were collected on 2 occasions, 1 week apart, in 20 different clinically normal dogs by use of a PSW; week-to-week variation in values was evaluated.

Results—Measurements of velocity derived by use of the photocells were not different from those derived by use of the PSW. For any 1 limb, values derived by use of the PSW were significantly lower than values derived with the FP. For values obtained by use of either technique, there were no differences between left and right limbs except for values of PVF measured via PSW in forelimbs. Values of PVF, VI, contact time, stride length, and static weight distribution generated by the PSW did not vary from week to week.

Conclusions and Clinical Relevance—Values for GRFs varied between the FP and PSW. However, data derived by use of PSW were consistent and could be used to evaluate kinetic variables over time in the same dog.

Full access
in American Journal of Veterinary Research

Abstract

OBJECTIVE To evaluate the impact of oral megestrol acetate (MA) administration on adrenal function in male bottlenose dolphins (Tursiops truncatus).

DESIGN Serial cross-sectional study.

ANIMALS 8 adult male dolphins, all of which were receiving MA at various daily doses (range, 0 to 60 mg, PO) for the control of reproductive behavior.

PROCEDURES Blood samples were collected every 2 weeks for 1 year from dolphins trained to voluntarily provide them. Cortisol, ACTH, and other hormone concentrations were measured in serum or plasma via radioimmunoassay or ELISA. Fecal samples, also provided by dolphins voluntarily, were assayed for glucocorticoid metabolite concentrations. Effects of daily MA dose on hormone concentrations were evaluated.

RESULTS Daily MA doses as low as 10 mg strongly suppressed cortisol secretion in nearly all dolphins, and except for a single measurement, no dolphin had measurable serum concentrations at doses ≥ 20 mg. Variations in serum cortisol concentration were unrelated to season but were directly related to ACTH concentrations, suggesting primary effects upstream of the adrenal gland. Cessation of MA administration resulted in almost immediate restoration of measurable serum cortisol concentrations, although concentrations continued to rise in a few dolphins over the following weeks to months.

CONCLUSIONS AND CLINICAL RELEVANCE Caution should be exercised when administering MA to control reproductive behavior in male dolphins. Because the hypothalamic-pituitary-adrenal axis appeared to be sensitive to even small doses of MA in dolphins, duration of treatment may be the most critical consideration.

Full access
in Journal of the American Veterinary Medical Association