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Abstract

Objective—To determine whether an anti-Salmonella bacterium is involved in control of pathogen load in persistently infected cattle herds.

Animals—24 Holstein calves experimentally infected and 39 Holstein cows naturally infected with Salmonella spp.

Procedures—An Escherichia coli (designated as P8E5) that possessed anti-Salmonella activity was isolated from Salmonella-negative bovine feces obtained from a herd with endemic Salmonella infection. In vitro analysis involved enumerating Salmonella enterica serovar Typhimurium coincubated with E coli P8E5. In vivo analysis involved coadministration of Salmonella spp and E coli P8E5 or an E coli control strain to neonatal Holstein calves. Fecal samples were collected on multiple days after inoculation, and quantitative PCR assay was performed by use of Salmonella-specific primers.

ResultsE coli P8E5 reduced viability of Salmonella spp in vitro. Shedding of Salmonella organisms was diminished in calves administered E coli P8E5, whereas the control strain of E coli had no effect on shedding of Salmonella organisms.

Conclusions and Clinical Relevance—In this study, an E coli strain was identified that possessed bacteriocin-like activity and was able to decrease viability of Salmonella organisms in vitro and in vivo. Therefore, it is possible that this organism could be representative of native microbiota that dampen Salmonella spp in persistently infected cattle herds.

Full access
in American Journal of Veterinary Research

Summary

The effect of feeding monensin, with or without dry hay plus wilted forage, on ruminal formation of 3-methylindole (3MI) was investigated in pastured cattle. Eighty-two cows were allotted to 3 groups. Cows of group-1 served as controls and were given a daily energy supplement (1 kg/head) without monensin for 1 day before and for 7 days after being allowed access to lush pasture. Cows of groups 2 and 3 were given the same daily energy supplement, which also contained monensin (200 mg/kg of supplement). Cows of group 3 also were fed dry hay for 5 days before the start of the study and continued to be given supplemental hay for 4 days after being allowed access to lush pasture containing a layer of wilted forage. Ruminal 3MI and indole concentrations increased on day 1 after all groups were allowed access to lush pasture. By day 7, 3MI concentration in all cows had decreased to pregrazing concentration. Indole concentration did not reach pregrazing concentration until day 10 for cows of groups 1 and 2. Group-3 cows had pregrazing indole concentration on day 7. Ruminal indole concentration did not differ (P > 0.05) between groups 1 and 2. Ruminal indole concentration was lower (P < 0.01) in group-3 cows on all sample collection days, except day 10, compared with that in the other groups. Monensin reduced (P <0.01) 3MI formation on days 1 and 7 in group-2 cows, compared with group-1 cows. Group-3 cows had lower 3MI concentration than did group-1 cows (P <0.01) on days –1, 1, 4, and 7. Monensin, when fed with dry hay and wilted forage, reduced (P <0.01) 3MI formation on days 4 and 7 in group-3 cows, compared with cows that were only given monensin (group 2). Group-3 cows also had lower (P < 0.05) 3MI concentration, compared with group-2 cows on day 1. Results indicated that monensin reduced ruminal formation of 3MI. Feeding dry hay and wilted forage to cattle during the change to lush pasture resulted in further reduction in the amount of 3MI formed by ruminal microorganisms. To maximize the effectiveness of monensin in reducing 3MI formation, dry hay plus wilted forage should be fed to pastured cattle for at least 4 days after they are allowed access to lush pasture.

Free access
in American Journal of Veterinary Research
in Journal of the American Veterinary Medical Association

Abstract

Case Description—An underweight, lethargic adult female California sea lion (Zalophus californianus) became stranded along the California shore and was captured and transported to a rehabilitation hospital for assessment and care.

Clinical Findings—Initial physical assessment revealed the sea lion was lethargic and in poor body condition. Active myositis was diagnosed on the basis of concurrent elevations in activities of alanine aminotransferase and creatine kinase detected during serum biochemical analysis. Infection with Sarcocystis neurona was diagnosed after serologic titers increased 4-fold over a 3-week period. Diagnosis was confirmed on the basis of histopathologic findings, positive results on immunohistochemical staining, and results of quantitative PCR assay on biopsy specimens obtained from the diaphragm and muscles of the dorsal cervical region.

Treatment and Outcome—Anticoccidial treatment was instituted with ponazuril (10 mg/kg [4.5 mg/lb], PO, q 24 h) and continued for 28 days. Prednisone (0.2 mg/kg [0.09 mg/lb], PO, q 12 h) was administered for 2 days and then every 24 hours for 5 days to treat associated inflammation. At the end of treatment, the sea lion was clinically normal, alanine aminotransferase and creatine kinase values were within reference limits, and antibody titers against S neurona had decreased 6-fold. The sea lion was released approximately 3 months after becoming stranded.

Clinical RelevanceS neurona–induced myositis was diagnosed in a free-ranging California sea lion. On the basis of the successful treatment and release of this sea lion, anticoccidial treatment should be considered for marine mammals in which protozoal disease is diagnosed.

Full access
in Journal of the American Veterinary Medical Association

SUMMARY

Objectives

To test effectiveness of an electrolyte paste in correcting fluid, electrolyte and acid base alterations in response to furosemide administration.

Animals

6 Standardbreds.

Procedures

Horses received electrolyte paste or water only (control). The paste was given orally 3 hours after furosemide administration (1 mg/kg of body weight, IM). Water was given ad libitum soon after the paste and 3 hours after furosemide administration to treated and control groups, respectively. Paste Na+, K+, and Cl composition was approximately 2,220, 620, and 2,840 mmol, respectively. The PCV and plasma concentrations of total protein ([TP]), [Na+], [K+], [Cl]), and bicarbonate ([HCO3 ]) were determined, and urinary fluid and electrolyte excretion, fecal water, and body weight changes were measured.

Results

At the end of a 6-hour period, the paste-treated group had higher water consumption, which resulted in lower plasma [TP]; net electrolyte losses also were substantially less. With paste administration, [Na+] was approximately 2 mmol/L above a prefurosemide value of 137.3 mmol/L; control horses had values similar to the prefurosemide value. Plasma [Cl] remained at the prefurosemide value, but values in control horses decreased by 7 mmol/L with water consumption. Plasma [K+] remained approximately 0.8 mmol/L below prefurosemide values in both groups. Venous [HCO3 ] returned to prefurosemide values after paste administration, but alkalosis persisted in control horses after consumption of water only. Body weight loss was less after paste administration.

Conclusions

Administration of electrolyte paste is advantageous over water alone in restoring fluid, electrolyte, and acid base balance after fluid and electrolyte loss attributable to furosemide administration. (Am J Vet Res 1998;59:898–903)

Free access
in American Journal of Veterinary Research

Abstract

Objective

To compare therapeutic benefits of intratumoral administration of cisplatin and bleomycin for squamous cell carcinoma of the eyelids in horses.

Animals

25 horses with 27 T2-stage periocular squamous cell carcinomas.

Procedure

Horses were treated 4 times at 2-week intervals with a slow-release formulation of cisplatin (1 mg/cm3 of tissue) or bleomycin (1 IU/cm3 of tissue). A two-stage design was used to minimize the sample size in each treatment arm.

Results

The local control rate at 1 year for lesions treated with cisplatin was 93 ± 6%, and with bleomycin was 78 ± 10%. Difference in local control duration between the 2 treatment groups was not significantly different. A high tumor proliferative fraction index value was associated with a higher local (in-field) control rate, but also with a higher risk of marginal and regional recurrences. Tumors with a low proliferative fraction index value (< 28%) had 9.5-times higher (P = 0.0411) risk of recurrence than those with a high index value. Local acute reactions were similar in the 2 treatment groups, and chronic reactions were not observed.

Conclusions

Cisplatin and bleomycin were effective anticancer agents for carcinoma of the eyelid in horses. Based on therapeutic benefit and treatment cost, cisplatin was found to be a better choice for intratumoral chemotherapy of eyelid carcinomas.

Clinical Relevance

Results of this study confirm the value of intratumoral chemotherapy, using cisplatin, for treatment of cutaneous squamous cell carcinomas in horses. (Am J Vet Res 1997;58:431–436)

Free access
in American Journal of Veterinary Research

Summary

Eleven horses (3 mares, 7 stallions, 1 gelding) with clinical and biochemical evidence of hyperkalemic periodic paralysis were studied. Each horse had history of episodic weakness, muscular tremors, or collapse, which lasted for periods of a few minutes to hours. Diagnosis was based on hyperkalemia in association with a spontaneous episode of paralysis or by precipitation of an episode by oral administration of potassium chloride. Clinical and biochemical events were documented during spontaneous and induced episodes of muscular weakness. During episodes, electrocardiographic findings were consistent with hyperkalemia. Electromyography performed between episodes revealed fibrillation potentials and positive sharp waves, complex repetitive discharges, and myotonic discharges. Histologic changes in muscle biopsy specimens varied from no overt changes in some horses to vacuolation in type-2B fibers with mild degenerative changes in other horses. Electron microscopy of myofibers revealed dilatations of the sarcoplasmic reticulum.

Analysis of blood samples taken serially during induced attacks in 5 horses revealed marked hyperkalemia (5.5 to 9.0 mEq/L), with normal acid-base status, hemoconcentration, and modest changes in muscle-derived enzymes. Close correlation (r 2 = 0.882) between total plasma protein and plasma potassium concentrations was observed and indicated a shift of fluid out of the extracellular fluid compartment. Treatment of either spontaneous or induced episodes by iv administration of calcium, glucose, or bicarbonate resulted in rapid recovery. Dietary management or daily administration of acetazolamide effectively controlled episodes.

An affected mare was bred to an affected stallion, and 3 affected offspring were produced by embryo transfer. Blood samples from another extended family of affected horses were analyzed for identification of a genetic marker. Blood typing, including 22 loci, revealed no linkage with erythrocytic or serum markers. Lymphocyte typing for equine lymphocytic antigen markers also failed to reveal any linkage.

Free access
in Journal of the American Veterinary Medical Association

SUMMARY

The vascular permeability of the ocular fundus, alterations in the coagulation system, and plasma concentrations of thromboxane B2 (txb 2) and 6-keto-prostaglandin F, (6-keto-pgf ) were studied in dogs following intradermal inoculation with 5 × 105 tcid 50 of Rickettsia rickettsii. Twenty-four to 48 hours after the onset of fever and rickettsemia, multifocal areas of retinal vasculitis were evident, which corresponded to areas of altered vascular permeability demonstrated by fluorescein angiography. The number and intensity of retinal vessels with sodium fluorescein leakage peaked during the second week after inoculation, and retinal vascular permeability remained altered during the third week of infection, well past the phase of clinical and clinicopathologic recovery.

Development of retinal vasculitic foci was associated with thrombocytopenia, increased concentrations of circulating fibrinogen, and slight prolongation of activated partial thromboplastin time. Increased concentrations of fibrin/fibrinogen degradation products were detected in 4 of 9 dogs. Despite the degree of vascular endothelial damage evident on fluorescein angiographic and histologic studies in these dogs, plasma txb 2 and 6-keto-pgf concentrations were not increased.

Free access
in American Journal of Veterinary Research