Comparison of pathophysiologic changes in the lungs of calves challenge exposed with Escherichia coli-derived endotoxin and Pasteurella haemolytica, alone or in combination

Pulmonary responses to intratracheal challenge exposure with Pasteurella haemolytica, with or without Escherichia coli-derived endotoxin, E coli endotoxin alone, or saline solution were compared in anesthetized, mechanically ventilated neonatal calves. Baseline values for dynamic compliance, total pulmonary resistance, functional residual capacity, arterial blood gas tensions, hemogram, leukogram, and systemic and pulmonary arterial pressures were recorded for each calf. After baseline data were obtained, calves were challenge exposed with logarithmic-growth phase P haemolytica organisms with or without E coli endotoxin, E coli endotoxin alone, or saline solution (0.9% NaCl). Physiologic data were obtained immediately after challenge exposure and at various intervals over the next 6 hours. Calves challenge exposed with P haemolytica alone developed sever hypoxemia, had increased alveolar-arterial oxygen difference and threefold increases in total pulmonary resistance, became hypercarbic, had decreased functional residual capacity, and developed systemic hypotension without change in pulmonary arterial pressure. At necropsy, these calves had extensive multifocal areas of necrohemorrhagic and purulent pneumonia. Ratio of extravascular lung water to lung dry weight was not significantly increased in lung specimens obtained from calves challenge exposed with P haemolytica, but ratio of lung wet weight to dry weight was increased, indicating that increased lung wet weight was attributable largely to increased solids and not to fluid alone. (Extravascular lung water measurement excludes fluid from the vascular compartment.) Intratracheal challenge exposure with endotoxin failed to alter lung function and caused minor changes in lung structure consisting of focal areas of hemorrhage and edema.(ABSTRACT TRUNCATED AT 250 WORDS)     

Gossypol toxicity in preruminant calves

SUMMARY Twenty-four of 57 calves fed a diet containing 33% cotton seed meal (CSM) died between 7 and 15 weeks of age. Initial deaths were not accompanied by premonitory signs, but after CSM withdrawal most calves developed rough coats, anorexia, weakness, ascites and subcutaneous oedema. Those that died had large volumes of serous fluid in the body cavities, hard livers of ‘nutmeg’ appearance, and pulmonary congestion. Histopathologically the livers showed periacinar necrosis in acute cases and periacinar fibrosis in chronic cases. Lungs from several calves had oedema, haemosiderosis and fibrosis in some pulmonary vessels. Atrophy of myocardial fibres was present in most cases. The concentration of free gossypol in the diet was 100 to 220 mg/kg. Ante-mortem and post-mortem findings supported a diagnosis of gossypol poisoning. The deaths continued for 4 weeks after withdrawal of CSM from the diet.     

Heartworm in dogs in Canada in 1991

In late November 1991, 1883 clinics in Canada were sent a questionnaire to assess the status of Dirofilaria immitis in dogs in 1991 and there was a 60.0% response. There were 344,031 dogs tested for heart-worm (HW), 627 were found infected and the prevalence of HW infection was 0.18%. There were 417 dogs with HW in Ontario, 116 in Manitoba, 38 in Quebec, 53 in British Columbia, three in Alberta, and one in Nova Scotia. In British Columbia, all of the infected dogs but one were from the Okanagan valley which, as from 1991, is a new focus of infection in Canada. Most dogs with HW had not been on preventive medication in 1990, and the prevalence among dogs tested and unprotected was 0.59%. That prevalence was considerably higher in endemic areas. Companion dogs, over three years of age and maintained primarily outdoors in rural areas, were most frequently infected. One cat was diagnosed with D. immitis and 33 dogs had Dipetalonema reconditium.     

Combined Streptomycin-Isoniazid-Rifampin Therapy in the Treatment of Johne's Disease in a Goat

Johne's disease (paratuberculosis) is an insidious, invariably fatal, chronic disease of ruminants. An increasing role for the goat as a companion animal as well as its commercial use stimulated interest in attempting to treat Johne's disease in this species. The disease tends to differ both clinically and pathologically in goats compared to cattle because the former species often has less severe intestinal involvement. It was, therefore, speculated that response to therapy may differ between cattle and goats. In addition, the combination drug regime of isoniazid, rifampin and streptomycin, widely accepted for human mycobacterial infections, has not been previously employed for treatment of Mycobacterium paratuberculosis. The clinical course and pathological findings of a case of naturally occurring Johne's disease subsequent to a combined drug regime of isoniazid, rifampin and streptomycin is discussed.     

The use of ultrasonography in the reproductive evaluation of boars

The objective was to study the use of ultrasound as a complementary test in the breeding soundness evaluation in male pigs and study the pattern of echogenicity of the testicular parenchyma in boars of different racial groups. Twenty‐six adult boars from four different racial groups were used, 10 from the Piau breed (group 1), four from the commercial and finishing group (group 2), six Pietrain breed (group 3) and six from the Duroc breed (group 4). All animals were evaluated for breeding soundness evaluation and the ultrasound examination of the testicles. The groups of animals that were evaluated showed no difference in the main semen parameters that were evaluated, except for the sperm volume, concentration of the ejaculated sperm and the supravital staining; the lowest figures were for the animals from the Piau breed (group 1). In relation to the testicular biometrics, Duroc animals (group 4) had a greater scrotal width compared to the other groups. But when we assessed the intensity of pixels of the testicles, there was a difference between groups. The groups 2 (finishing animals), 3 (Pietrain) and 4 had no difference between themselves. Group 3 had greater pixel intensity in relation to group 1. Of the 26 animals studied, five showed an abnormality during ultrasound evaluation, like hydrocele, hyperechoic mass in the testicular parenchyma, cyst in the head of the epididymis and the presence of fluid in the head and tail of the epididymis. The various animal groups studied did not differ in the principal reproductive parameters evaluated, showing that despite the great variability of reproductive traits between breeds and within the same breed, the breeding soundness evaluation, the more complete it is, is essential for the selection of breeders and the ultrasonography of the reproductive system becomes an important addition in this examination.     

Risk factors for Thoroughbred racehorse fatality in jump starts in Victoria, Australia (1989-2004)

REASONS FOR PERFORMING STUDY: The risk of fatality is greater in jump than in flat racing in Victoria, Australia. This is the first study to identify risk factors specific to jump starts in Victoria. OBJECTIVE: To identify risk factors for fatality of Thoroughbred racehorses in jump starts on all racecourses in Victoria, Australia between 1989 and 2004. METHODS: Fatalities comprised all horses that died during or immediately after a jump (hurdle or steeplechase) race or official jump trial and all horses that were subjected to euthanasia within 24 h of an event in which an injury was sustained. The retrospective study involved 191 case starts and 2324 control starts. Univariable and multivariable backward stepwise logistic regression was used to identify risk factors for fatality at any one start. A multiple level model was used with racecourse included as a random effect. RESULTS: In the final multivariable model, the duration of the racing career of the horse, the number of flat, hurdle and steeple starts accumulated in the 60 days prior to the case or control start, the number of flat and jump starts accumulated over the racing career, if the horse had had a start between 1 and 14 days prior to the case or control start, the type of jump race (hurdle or steeple), the calendar year of the start and the location of the racecourse were associated with fatality. CONCLUSIONS: The findings highlight the need to investigate further the differences between hurdle and steeplechase events and the adverse effect of prolonged prior flat racing careers on the risk of fatality in jump starts. POTENTIAL RELEVANCE: This is the first study to examine risk factors for fatality in jump starts in Victoria. The results should shape the development of interventions to reduce the risk in jump starts in the future.