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Abstract

Objective—To ascertain the frequency of ultrasonographic identification of liver at sites recommended for blind percutaneous liver biopsy in middle-aged horses and to determine whether the liver is obscured by other organs or too thin for safe sample collection at recommended locations.

Design—Prospective case series.

Animals—36 healthy middle-aged (between 6 and 18 years old) Quarter Horses or Quarter Horse crosses.

Procedures—Blood samples were collected from each horse and submitted for evaluation of liver function. Horses with any indication of liver dysfunction on serum biochemical analysis were excluded. The region just below a line drawn between the dorsal aspect of the tuber coxae and the point of the elbow joint in the right 11th, 12th, 13th, and 14th intercostal spaces (ICSs) was imaged by ultrasonography for the presence of liver. In each ICS, liver thickness and whether there was partial obstruction in viewing the liver caused by other abdominal or thoracic organs were recorded.

Results—39% (14/36) of horses had liver imaged on ultrasonographic examination in all of the 11th to 14th ICSs. None of the 36 horses had liver of adequate thickness (ie, liver thickness ≥ 3.5 cm) for biopsy in all of the imaged ICSs. For 22 horses in which the liver was not visible on ultrasonographic examination of an ICS, lung was imaged instead in 12 (55%) horses, intestine in 8 (36%), and both intestine and lung in 2 (9%).

Conclusions and Clinical Relevance—On the basis of the results of this study, the practice of blind percutaneous liver biopsy in horses is not recommended because of the risk of serious complications.

Full access
in Journal of the American Veterinary Medical Association

Abstract

Objective—To describe frequency, types, and clinical outcomes of extrapulmonary disorders (EPDs) in foals in which Rhodococcus equi infection was diagnosed, and to identify factors determined at the time of admission that differentiated foals that developed EPDs from foals with R equi infection identified only in the lungs.

Design—Retrospective case series.

Animals—150 foals aged 3 weeks to 6 months with a diagnosis of R equi infection.

Procedures—Medical records were reviewed for information on date of admission, signalment, history, clinical signs, diagnostic testing, treatment, duration of hospitalization, invoice, and outcome. For each EPD identified, further information was collected on the identification, location, treatment, and outcome of the lesion.

Results—Of 150 foals with R equi infections, 111 (74%) had at least 1 of 39 EPDs. Survival was significantly higher among foals without EPDs (32/39 [82%]) than among foals with EPDs (48/111 [43%]), but many EPDs were only recognized after death. Risk factors significantly associated with EPDs included referral status, duration of clinical signs prior to admission, leukocytosis, and neutrophilia. Foals with EPDs also had a higher heart rate and BUN concentration than foals without.

Conclusions and Clinical Relevance—Practitioners should recognize that extrapulmonary manifestations of R equi occur with high prevalence affecting diverse organ systems, that multiple systems are generally affected when EPDs occur, and that suspicion of R equi infection should prompt evaluation and monitoring of extrapulmonary sites. Improved recognition of the presence of these disorders will help practitioners to better advise their clients in the treatment and outcome of foals with R equi infections.

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in Journal of the American Veterinary Medical Association

Abstract

Objective—To assess signalment, history, results of clinical and laboratory testing, and outcome for beef cattle with a left displaced abomasum (LDA), right displaced abomasum (RDA), or abomasal volvulus (AV).

Design—Retrospective study.

Animals—19 beef cattle with an AV, LDA, or RDA.

Procedure—Signalment; history; results of physical examination, diagnostic testing, and surgical exploration; and condition of the animal at discharge were obtained from medical records.

Results—Fourteen cattle had an AV, 4 had an RDA, and 1 had an LDA. Duration of clinical signs ranged from 1 to 21 days. Eighteen cattle had an AV or RDA; 7 were Brahmans, 12 were males, and median age was 10 months. Abdominal distention was observed in 11 cattle, heart rate of ≥ 100 beats/minute was detected in 14, and the abomasum was palpable per rectum in all cattle in which per rectal examination was performed. Leukocytosis, neutrophilia, hyperglycemia, azotemia, hypochloremia, and hypokalemia were common laboratory findings. At surgery, 3 cattle with an AV or RDA had a ruptured abomasum. Of the remaining 15 cattle, 12 survived.

Conclusions—Clinical course in beef cattle with an AV or RDA was more protracted than that typically associated with these conditions in dairy cattle, but survival rate in beef cattle that did not have rupture of the abomasum was sim ilar to that of dairy cattle.

Clinical Relevance—Abomasal displacement should be considered for beef cattle with abdominal distention. Prognostic indicators recommended for use in dairy cattle may not be useful for beef cattle. (J Am Vet Med Assoc 2000;216:730–733)

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in Journal of the American Veterinary Medical Association

Abstract

Objective—To identify risk factors for enterolithiasis in horses.

Design—Matched case-control study.

Animals—26 horses with enteroliths, 104 horses with other causes of colic that underwent surgery (52 horses, surgical control group) or were treated medically (52 horses, nonsurgical control group).

Procedure—Medical records were reviewed for horses with enteroliths and control horses. Information collected included signalment, anamnesis, and findings on physical examination and clinicopathologic testing at admission. Horses with enteroliths and control horses were compared by means of conditional logistic regression to identify factors associated with enterolithiasis.

Results—Horses that were fed alfalfa hay, spent ≤ 50% of time outdoors, or were Arabian or miniature breeds had an increased risk of developing enteroliths. Horses with enteroliths were more likely to have been hyperbilirubinemic and to have had clinical signs > 12 hours prior to admission.

Conclusions and Clinical Relevance—Breed and diet appear to influence the risk of enterolithiasis; other management factors also may influence development of enteroliths. Duration of clinical signs may be longer and signs may be less severe among horses with enteroliths, compared with horses with other causes of colic. (J Am Vet Med Assoc 2000;216:1787–1794)

Full access
in Journal of the American Veterinary Medical Association

Abstract

Objective—To identify farm characteristics as risk factors for the development of Rhodococcus equi pneumonia in foals.

Design—Prospective matched case-control study.

Animals—2,764 foals on 64 equine breeding farms with 9,991 horses.

Procedure—During 1997, participating veterinarians completed paired data collection forms, 1 for a farm with ≥ 1 foal with R equi pneumonia and 1 for an unaffected control farm. Matched data were compared by use of conditional logistic regression analysis.

Results—Farm characteristics found in bivariate analyses to be associated with increased risk for pneumonia caused by R equi in foals included > 200 farm acres, ≥ 60 acres used in the husbandry of horses, > 160 horses, ≥ 10 mares housed permanently on the farm (resident mares), > 17 foals, > 0.25 foals/acre, and the presence of transient mares (mares brought temporarily to the farm for breeding or foaling) and their foals. Affected farms were significantly more likely to be > 200 acres in size and have ≥ 10 resident dam-foal pairs, whereas control farms were significantly more likely to have ≥ 75% of their dam-foal pairs housed permanently on the farm.

Conclusions and Clinical Relevance—Breeding farms with large acreage, a large number of mares and foals, high foal density, and a population of transient mares and foals are at high risk for foals developing pneumonia caused by R equi. (J Am Vet Med Assoc 2003;222:467–475)

Full access
in Journal of the American Veterinary Medical Association

Abstract

Objective—To determine whether foal management practices, environmental management, and preventative health practices are risk factors for development of Rhodococcus equi pneumonia in foals.

Design—Prospective matched case-control study.

Animals—2,764 foals on 64 equine breeding farms with 9,991 horses.

Procedure—During 1997, participating veterinarians completed paired data collection forms for comparison; 1 for an affected farm (containing ≥ 1 foal with pneumonia caused by R equi)and 1 for a control farm. Information collected pertained to stabling facilities, environmental management, foal husbandry, and preventative equine health practices.

Results—Matched farm data compared by use of conditional logistic regression indicated that personnel on affected farms were more likely to attend foal births, test foals for adequacy of passive immunity, administer plasma or other treatments to foals to supplement serum immunoglobulin concentrations, administer hyperimmune plasma prophylactically to foals, vaccinate mares and foals against Streptococcus equi infection, and use multiple anthelmintics in deworming programs. Affected farms were also more likely to have foals that developed other respiratory tract disorders and were approximately 4 times as likely to have dirt floors in stalls used for housing foals as were control farms.

Conclusions and Clinical RelevanceRhodococcus equi pneumonia does not appear to be associated with poor farm management or a lack of attention to preventative health practices. Housing foals in stalls with dirt floors may increase the risk for development of R equi pneumonia. (J Am Vet Med Assoc 2003; 222:476–485)

Full access
in Journal of the American Veterinary Medical Association

Objective

To identify features of guttural pouch (auditory tube diverticulum) empyema in horses and compare findings of uncomplicated guttural pouch empyema with guttural pouch empyema complicated by chondroids.

Design

Retrospective study.

Animals

91 horses with guttural pouch empyema.

Procedure

Medical records of horses with guttural pouch empyema were reviewed.

Results

The most common owner complaint and abnormal finding was persistent nasal discharge. Chondroids were detected in 21% (19/91) of affected horses. Streptococcus equi was isolated from the guttural pouch in 14 of 44 horses; for Streptococcus spp, in vitro resistance to sulfadimethoxine and trimethoprim-sulfamethoxazole was detected. Retropharyngeal swelling and pharyngeal narrowing were significantly more prevalent in horses with chondroids, compared with horses with uncomplicated empyema. Ninety-three percent of affected horses were discharged from the hospital; at time of discharge, 66% had complete resolution of disease, 19% had improvement without resolution, and 15% did not have improvement.

Conclusions and Clinical Relevance

Horses with persistent nasal discharge should be examined endoscopically for guttural pouch empyema. Treatment with lavage offers a good prognosis for resolution of uncomplicated guttural pouch empyema. Aggressive treatment with lavage and endoscopic snare removal of chondroids offers a good prognosis and may make surgical intervention unnecessary. (J Am Vet Med Assoc 1999;215:1666–1670)

Free access
in Journal of the American Veterinary Medical Association

Objective

To determine whether dietary and other management factors were associated with development of colic in horses.

Design

Prospective matched case-control study.

Population

2,060 horses examined by veterinarians in private practice in Texas for colic and noncolic emergencies.

Procedure

Each month for 12 months, participating veterinarians were sent forms to collect information on 1 horse with colic and 1 horse that received emergency treatment for a condition other than colic. Information collected included signalment, farm management and characteristics, diet, medical and preventive medical factors, transport, and activity or use. Case and control horses were compared by means of conditional logistic regression to identify factors associated with colic.

Results

Recent change in diet, recent change in type of hay, history of previous episode of colic, history of abdominal surgery for colic, recent change in weather conditions, recent change in housing, Arabian breed, administration of an anthelmintic during the 7-day period prior to examination, failure to receive regular deworming, age > 10 years, and regular exercise (vs pastured at all times) were associated with increased risk of colic.

Conclusions and Clinical Relevance

Results suggest that changes in diet (particularly in type of hay fed) contribute to increased risk of colic. A regular program for administration of anthelmintics may reduce the overall frequency at which colic develops, but recent administration of anthelmintics may predispose some horses to colic. Arabian horses may have an increased risk of colic, and horses at pasture may have a decreased risk of colic. (J Am Vet Med Assoc 1999;215:53-60)

Free access
in Journal of the American Veterinary Medical Association

Objective

To determine prevalence of and risk factors for fecal shedding of Cryptosporidium parvum oocysts among 3 populations of horses.

Design

Cross-sectional study.

Animals

152 horses participating in the 1996 Texas State 4-H Horse Show, 144 horses examined by the veterinary teaching hospital, and 70 broodmares and their 10- to 21-day-old foals.

Procedure

Information on signalment and potential risk factors for fecal shedding of oocysts was obtained. Fecal samples were evaluated for oocysts by means of acid-fast (AF) staining, immunofluorescence assay (IFA), and, for selected samples, flow cytometry (FC).

Results

Results of the 3 diagnostic tests were significantly different. The best agreement was between results of the IFA and FC; AF staining and FC were more sensitive than the IFA, but AF staining was less specific. Fecal samples from 13 horses were classified as positive for oocysts. Risk factors for fecal shedding of oocysts included residence on 2 of 4 breeding farms involved in the study, age < 6 months, and history of diarrhea during the preceding 30 days. A municipal water source was implicated as a risk but could not be verified because of insufficient data.

Clinical Implications

Mature horses and exposure to cattle did not appear to be important sources of cryptosporidial infection for foals. Overall prevalence of C parvum infection among these horses was low, and C parvum infection appeared to be associated with particular farms, rather than an endemic opportunistic infection in horses.

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in Journal of the American Veterinary Medical Association

Summary

Medical records of 116 horses admitted to the Texas Veterinary Medical Center between Jan 1, 1984 and Dec 31, 1991 with duodenitis/proximal jejunitis (dpj) were reviewed. The prevalence of laminitis was 28.4% (33/116; 95% confidence interval: 20.2 to 36.6%). The prevalence of dpj and DPJ-associated laminitis did not appear to vary significantly by year during the study period. Anamnesis, physical examination, clinicopathologic data, and initial treatment recorded at the time of admission were reviewed to determine risk factors associated with development of laminitis associated with dpj. A trend of increasing prevalence of laminitis with increasing weight was observed. Using a multiple logistic regression model, horses weighing ≥ 550 kg were approximately twice as likely to develop laminitis than horses weighing < 550 kg (P = 0.048). Horses with hemorrhagic reflux observed at the time of admission were nearly twice as likely to develop laminitis than horses without hemorrhagic reflux (P = 0.022).

Treatments administered prior to admission or at our clinic did not significantly affect development of laminitis, except for administration of heparin to prevent laminitis. Of 33 horses that developed laminitis associated with dpj, 2 had laminitis at the time of admission. These 2 horses were excluded from analysis of the effects of heparin administered as prophylaxis for laminitis; neither horse was treated with heparin. The proportion of horses that developed laminitis among horses that received heparin (0.0%; 0/12) was significantly (P = 0.018) less than that among horses that did not receive heparin (29.8%; 31/104). Because of the small number of horses that received heparin and the retrospective design of this study, the clinical importance of this association could not be determined.

Free access
in Journal of the American Veterinary Medical Association