Effect of pH, temperature and media on acid and alkaline phosphatase activity in "clinical" and "nonclinical" isolates of Bordetella bronchiseptica.

Twenty-two isolates of Bordetella bronchiseptica were studied to determine the effects of pH, incubation temperature and type of media on peak acid and alkaline phosphatase activity. The pH optimum for alkaline phosphatase activity was 9.0 for all of the isolates tested. The pH optimum for acid phosphatase activity was 5.8 for 67% of the isolates and 4.8 for 33%. All of the isolates showed peak phosphatase activity at 37 degrees C. No preference was shown in 35% of the isolates between the types of media tested; however, 40% preferred tryptose broth, 20% preferred nutrient broth and 5% preferred brain-heart infusion broth. No relationship was shown between phosphatase activity and the mouse lethality of the isolates.     

Tuberculosis in imported red deer (Cervus elaphus)

An outbreak of tuberculosis due to Mycobacterium bovis in farmed red deer imported from an eastern European country is described. Twenty-six of the 106 deer examined at autopsy were found to be infected and 19 had visible lesions of tuberculosis. Single comparative intradermal tuberculin tests on 51 deer showed that the test had a specificity of 61.3 per cent and a sensitivity of 80 per cent relative to subsequent biological and cultural tests on tissues taken at autopsy. Three hundred and seventy eight culled fallow and sika deer which had been running in a park in contact with some of the infected animals were found to be free of tuberculosis.     

An Echocardiographic Study of Atrial Fibrillation in Horses: Before and After Conversion to Sinus Rhythm

Two-dimensional and M-mode echocardiograms were recorded from 41 horses before they were successfully treated for atrial fibrillation. In addition, these examinations were performed in a subgroup of 20 horses after treatment, and the results were compared with pretreatment values. Atrial fibrillation in this group of horses was associated with a reduction of mean left ventricular fractional shortening (mean 31 %± 5.24%), and 22 of the 41 horses were below the reference range. The remaining mean M-mode variables were within the normal reference range, although 12 horses had increased left ventricular lumen dimensions in systole, and 8 horses had decreased left ventricular ejection times. Abnormal motion of the mitral valve was present in all horses and was characterized by the absence of A peaks, which were replaced by small diastolic undulations in 55% of the horses. In horses 1 to 20, after conversion to sinus rhythm, the mean fractional shortening increased (35.34%± 5.4%, P = .004), but there were no significant differences in heart rate or left ventricular lumen diameters in systole or diastole. These results suggest that ventricular function may be compromised by the presence of atrial fibrillation. However, this improved after correction of the arrhythmia.     

Use of the fluorochromes xylenol orange, calcein green, and tetracycline to document bone deposition and remodeling in healing fractures in chickens.

The fluorescent calcium binding dyes xylenol orange, calcein green, and tetracycline were used successfully to sequentially label new bone deposition and bone remodeling during the healing of rigidly fixed humeral fractures in the chicken. Xylenol orange and calcein green, administered subcutaneously at 90 mg/kg and 10 mg/kg, respectively, provided easily identified and differentiated bands in newly deposited bone within periosteal and endosteal calluses, intercortical gaps, and screw holes. Tetracycline, administered at 50 mg/kg per os by crop tube, labeled bone faintly in a non-specific manner. Parenteral administration of the same compound might have yielded better results.     

Brucella suis biovar 3 infection in a Kentucky swine herd

Sows from a large farrow-to-finish operation in western Kentucky had late-term abortions. Boars and breeding-age sows were tested serologically for brucellosis, and 83 of 125 were classified as reactors. No brucellae were isolated from the tissues of 6 unbred reactor sows, but Brucella suis biovar 3 was recovered from 5 aborted fetuses. Epidemiological studies failed to determine the source of the infection.     

Toxicity of Riddell's groundsel (Senecio riddellii) to cattle

The toxicity of Riddell's groundsel (Senecio riddellii) fed to calves in gelatin capsules, by gavage, or mixed in their hay ration was determined. Dosages were varied according to the pyrrolizidine alkaloid (PA) content of the plant, and the calves' responses were measured by clinical signs, serum enzyme changes, survival time, and histopathologic changes. Calves fed S riddellii to provide 10 mg of PA/kg of body weight/day in capsules or by gavage for 20 consecutive days did not develop clinical signs of seneciosis and did not have meaningful serum enzyme changes. However, feedings of the plant that provided 15 to 20 mg of PA/kg/day or more (gavaged or fed in capsules for the same time period) resulted in high mortality. The Senecio plant mixed in calves' hay ration was eaten slowly and reluctantly and was tolerated at dosages greater than 20 mg/kg/day, emphasizing that the toxicity was dependent on the rate at which the dosage was consumed and that mortality was not necessarily dependent on the cumulative dosage. Because of its high PA content, S riddellii presents a great hazard to cattle managed under conditions where they can consume quantities of the plant in short periods of time.