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Objective

To determine prevalence of clostridial enterotoxins in feces of horses with diarrhea and colic, and to determine whether an association exists between detection of clostridial enterotoxins in feces and development of diarrhea as a complication of colic.

Design

Prospective case series and case-control study.

Animals

174 horses with diarrhea, colic, or problems not related to the gastrointestinal tract.

Procedure

Horses were assigned to 1 of 4 groups: colic with diarrhea (group 1; n = 30); colic without diarrhea (group 2; 30); diarrhea without colic (group 3; 57); and control (group 4; 57). Feces were evaluated by use of ELISA to detect Clostridium perfringens enterotoxin (CPE) and C difficile toxin A (TOXA). Frequency of detection of CPE or TOXA in groups 1 and 3 was compared with that in groups 2 and 4, respectively.

Results

Prevalence of enteric clostridiosis in horses in group 3 was 25%. Clostridium perfringens enterotoxin was detected in 9 of 57 (16%), TOXA in 8 of 57 (14%), and both toxins in 3 of 57 (5%) fecal samples collected from these horses. Neither toxin was detected in feces of the age-matched horses in group 4. Clostridial enterotoxins were detected in feces of 7 of 60 (12%) horses with colic (groups 1 and 2); however, a significant association was not found between detection of enterotoxins in feces and development of diarrhea as a complication of colic.

Conclusions and Clinical Relevance

Clostridia are important etiologic agents of diarrhea in horses. Additionally, changes in intestinal flora of horses with colic may allow for proliferation of clostridia and elaboration of enterotoxins regardless of whether diarrhea develops. (J Am Vet Med Assoc 1999;215:358–361)

Free access
in Journal of the American Veterinary Medical Association

Objective

To determine results of CSF analysis in horses with equid herpesvirus myeloencephalopathy (EHM) and to determine whether results of CSF analysis were associated with outcome.

Design

Retrospective study.

Animals

11 horses.

Procedure

Medical records of all horses admitted to the veterinary teaching hospital between February 1982 and March 1996 in which EHM was diagnosed were reviewed.

Results

7 horses were ≤ 4 years old; 8 were admitted during January, February, or March. Six horses were febrile prior to admission, but none was febrile on the day of admission. Five horses had been stabled with other horses that had clinical signs of neurologic disease. All horses had had an acute onset of hind limb ataxia and paresis. Cranial nerve deficits were detected in 3 horses. Cerebrospinal fluid samples were collected on the day of admission from 10 horses. Protein concentration was high in 8 horses; nucleated cell count was normal in 8. Protein concentration and nucleated cell and RBC counts were not significantly different between horses that survived and horses that were euthanatized. Six horses were euthanatized, and 5 survived. All of the horses that survived remained standing or were able to stand with minimal assistance.

Clinical Implications

High CSF protein concentration and normal or only slightly high CSF nucleated cell count are common in horses with EHM; however, results of CSF analysis were not associated with outcome. Horses with EHM that become recumbent have a poor prognosis for survival. (J Am Vet Med Assoc 1998;213:671-675)

Free access
in Journal of the American Veterinary Medical Association

Abstract

Objective—To investigate effects of sample handling, storage, and collection time and season on plasma α-melanocyte-stimulating hormone (α-MSH) concentration in healthy equids.

Animals—11 healthy Standardbreds and 13 healthy semiferal ponies.

Procedure—Plasma α-MSH concentration was measured by use of radioimmunoassay. Effects of delayed processing were accessed by comparing α-MSH concentrations in plasma immediately separated with that of plasma obtained from blood samples that were stored at 4oC for 8 or 48 hours before plasma was separated. Effects of suboptimal handling were accessed by comparing α-MSH concentrations in plasma immediately stored at -80°C with plasma that was stored at 25°C for 24 hours, 4oC for 48 hours or 7 days, and –20°C for 30 days prior to freezing at –80°C. Plasma α-MSH concentrations were compared among blood samples collected at 8:00 AM, 12 noon, and 4:00 PM. Plasma α-MSH concentrations were compared among blood samples collected in January, March, April, June, September, and November from horses and in September and May from ponies.

Results—Storage of blood samples at 4°C for 48 hours before plasma was separated and storage of plasma samples at 4°C for 7 days prior to freezing at –80°C resulted in significant decreases in plasma α-MSH concentrations. A significantly greater plasma α-MSH concentration was found in September in ponies (11-fold) and horses (2-fold), compared with plasma α-MSH concentrations in spring.

Conclusions and Clinical Relevance—Handling and storage conditions minimally affected plasma α-MSH concentrations. Seasonal variation in plasma α-MSH concentrations must be considered when evaluating pituitary pars intermedia dysfunction in equids. (Am J Vet Res 2004;65:1463–1468)

Full access
in American Journal of Veterinary Research

Abstract

Objective—To evaluate the correlation between plasma α-melanocyte-stimulating hormone (α-MSH) concentration and body mass index (BMI) in healthy horses.

Animals—82 healthy horses.

Procedure—Plasma α-MSH concentration was determined by radioimmunoassay. At the time blood samples were collected, body condition scores (BCS) were determined and measurements of girth circumference, body length, and height were obtained. Weight was estimated by use of the following formula: estimated weight (kg) = [girth (cm)2 × length (cm)]/11,877. Body mass index was calculated as estimated weight (kg)/height (m)2.

Results—A correlation was found between BMI and BCS (r s = 0.60 [95% confidence interval (CI), 0.44 to 0.73]). A weak correlation was found between plasma α-MSH concentration and BMI (r s = 0.25 [95% CI, 0.03 to 0.45]) and BCS (rs = 0.26 [95% CI, 0.04 to 0.46]). A correlation was found between plasma α-MSH concentration and BMI in horses ≥ 10 years old (r s = 0.49 [95% CI, 0.20 to 0.69]) but not in horses < 10 years old (r s = –0.04). Horses in the upper quartile of BMI had significantly greater plasma α-MSH concentration (median, 9.1 pmol/L; range, 2.0 to 95.3 pmol/L) than horses in the lowest quartile of BMI (median, 7.0 pmol/L; range, 3.6 to 15.7 pmol/L).

Conclusions and Clinical Relevance—A correlation exists between plasma α-MSH concentration and BMI in horses. Further study is required to determine whether melanocortin receptor defects underlie this correlation or, alternately, whether plasma α-MSH concentration is simply a correlate of adiposity. (Am J Vet Res 2004;65:1469–1473)

Full access
in American Journal of Veterinary Research

Abstract

Objective—To determine prevalence and clinical features of pituitary pars intermedia dysfunction (PPID) in horses with laminitis.

Design—Case series.

Animals—40 horses with laminitis.

Procedures—Horses with laminitis that survived an initial episode of pain and were not receiving medications known to alter the hypothalamic-pituitary-adrenal axis were tested for PPID by evaluation of endogenous plasma ACTH concentration. Signalment, suspected cause, month of onset and duration of laminitis, Obel grade of lameness, pedal bone rotation, physical examination findings, results of endocrine function tests, treatment, outcome, and postmortem examination findings were recorded.

Results—Prevalence of PPID as defined by a single high plasma ACTH concentration was 70%. Median age of horses suspected of having PPID (n = 28) was 15.5 years, and median age of horses without PPID (12) was 14.5 years. Laminitis occurred most frequently in horses with and without suspected PPID during September and May, respectively. Chronic laminitis was significantly more common in horses suspected of having PPID. In horses suspected of having PPID, the most common physical examination findings included abnormal body fat distribution, bulging supraorbital fossae, and hirsutism. Five horses suspected of having PPID had no clinical abnormalities other than laminitis. Seventeen horses suspected of having PPID that were treated with pergolide survived, and 3 horses that were not treated survived.

Conclusions and Clinical Relevance—Evidence of PPID is common among horses with laminitis in a primary-care ambulatory setting. Horses with laminitis may have PPID without other clinical signs commonly associated with the disease. (J Am Vet Med Assoc 2004;224:1123–1127)

Full access
in Journal of the American Veterinary Medical Association