Estimation of transmission parameters of a fluoroquinolone-resistant Escherichia coli strain between pigs in experimental conditions

Antimicrobial resistance is of primary importance regarding public and animal health issues. Persistence and spread of resistant strains within a population contribute to the maintenance of a reservoir and lead to treatment failure. An experimental trial was carried out to study the horizontal transmission of a fluoroquinolone-resistant Escherichia coli strain from inoculated to naïve pigs. All naïve contact pigs had positive counts of fluoroquinolone-resistant E. coli after only two days of contact. Moreover, re-infections of inoculated pigs caused by newly contaminated animals were suspected. A maximum likelihood method, based on a susceptible-infectious-susceptible (SIS) model, was used to determine the transmission parameters. Two transmission levels were identified depending on the quantity of bacteria shed by infected individuals: (i) low-shedders with bacterial counts of resistant E. coli in the faeces between 5*10³ and 10⁶ CFU/g (β_L = 0.41 [0.27; 0.62]), (ii) high shedders with bacterial counts above 10⁶ CFU/g (β_H = 0.98 [0.59; 1.62]). Hence, transmission between animals could be pivotal in explaining the persistence of resistant bacteria within pig herds.     

Cytochemical staining characteristics of lymph nodes from normal and lymphoma-affected dogs

Frozen sections and imprint smears were used to evaluate the presence and pattern of cytochemical staining reactions in the B- and T-cell regions of lymph nodes from normal dogs and dogs with lymphoma. Staining procedures evaluated included peroxidase (PER), Sudan black B (SBB), naphthol AS-D chloroacetate esterase (CAE), alpha-naphthyl butyrate esterase (NBE), acid phosphatase (ACP), and leukocyte alkaline phosphatase (LAP). In normal lymph nodes, macrophages and some lymphocytes within the interfollicular (T-cell) region and medulla stained positive with ACP and NBE. Smaller numbers of macrophages also occurred sporadically within the germinal follicles. Cells positive for PER, SBB, and CAE were scattered infrequently throughout all regions of the normal lymph node, consistent with granulocytes and mast cells. The LAP stained cells were predominantly and prominently located within the mantle zone of secondary follicles and to a much lesser extent within the germinal centers, compatible with B-cell lymphocytes derived from follicular center cells. Of the 12 dogs with lymphoma, 7 cases (4 immunoblastic, 2 large noncleaved, 1 small noncleaved) stained diffusely positive with LAP, 4 cases (all lymphoblastic) had numerous focally positive lymphocytes using ACP and NBE, and 1 case (immunoblastic) did not stain positive with any of the cytochemical reactions. Cytochemical staining of canine lymph nodes with NBE, ACP, and LAP proved useful in distinguishing between B- or T-cell regions and detecting different cell types of canine lymphoma.     

Comparison of bronchoalveolar lavage findings and measurements of gas exchange during exercise in horses with poor racing performance

Twenty-four Thoroughbred and twelve Standardbred racehorses aged between 2 and 6 years, presented for reported poor racing performance, underwent clinical exercise testing. During the last 10 s of exercise at each speed throughout an incremental speed exercise test on a treadmill inclined at a 10% slope, samples of arterial blood and expired gases were collected. Maximum oxygen uptake and the partial pressures of oxygen and carbon dioxide in arterial blood were determined. These values were compared between the two breeds of horses and also with reference to cytological findings of bronchoalveolar lavage samples, including neutrophil, erythrocyte and haemosiderophage percentage and the total nucleated cell concentration. The results revealed an inverse relationship (Spearman R = -0.45, p < 0.05) between the total nucleated cell count in bronchoalveolar lavage samples and arterial oxygen partial pressure during exercise at 11 m.s(-1). This result suggests that subclinical pulmonary disease may be a more important cause of poor racing performance than previously thought. Also of note was a positive correlation (Spearman R = 0.50, p < 0.05) between maximum oxygen uptake and the percentage of erythrocytes.     

Femoral fracture repair complicated by vascular injury in a foal

A comminuted, mid-diaphyseal femoral fracture was diagnosed radiographically in a 4-month-old Quarter Horse colt. Disruption of the distal blood supply was suspected, as evidenced by coolness and diminished pulses of the distal portion of the limb. The fracture was repaired by compression plating but the foal's condition continued to deteriorate. A femoral arteriogram of the affected limb was obtained. Positive contrast agent was visible only as far as the mid-shaft of the femur. The foal was euthanatized and the postmortem examination revealed a transected popliteal artery accounting for ischemic necrosis of the distal limb.     

Effects of Ω-3 (n-3) Fatty Acid Supplementation on Insulin Sensitivity in Horses

The objective of this study was to examine the effects of dietary ω-3 fatty acid supplementation on insulin sensitivity (SI) in horses. Twenty-one mares were blocked by age, body weight (BW), and body condition score (BCS) and randomly assigned to one of three dietary treatments. Treatments consisted of (1) 38 g of n-3 fatty acids via fish and algae supplement and diet (MARINE), (2) 38 g of n-3 fatty acids via a flaxseed meal from the supplement and diet (FLAX), and (3) control (CON) no supplemental fatty acid. Treatments were supplemented for 90 days. Frequent sampling intravenous glucose tolerance tests were performed on days 0, 30, 60, and 90. Blood samples were analyzed for glucose and insulin. The minimal model was applied for the glucose and insulin curves using MinMod Millennium. SI increased 39% (P < .007) across all treatment groups. Acute insulin response to glucose decreased 22% (P < .006) between days 30 and 60 and increased (P = .040) again at day 90. Disposition index (combined SI and β pancreatic response) increased (P = .03) by 53% in the MARINE- and 48% in the FLAX-supplemented horses and did not change with time in the CON group. In insulin-resistant mares, MARINE- and FLAX-treated horses had an increase in SI (P = .09). It would be interesting to test this supplement in a larger group of insulin-resistant horses. If proven effective, supplementation with ω-3 fatty acids would help to reduce problems associated with insulin resistance in horses.     

Minimum space allowance for transportation of swine by road

Space allowance for animals in transit is a consistent concern in many countries that are developing codes of practice and regulations to assure humane treatment of food producing animals. The minimum space allowance requirements for a broad size range of swine in transit has not been well described or scientifically substantiated. A maximal loading pressure recommendation for pigs weighing from 5 to 250 kg was derived by a consultative process involving the swine transportation industry, animal welfare groups, and a literature review. The recommended maximal loading pressure under ideal conditions for swine loaded in groups can be described as a hoerl model y = (37.53)(0.9969)w(W0.5008), where y = loading pressure in kg body weight/m2 and W = average animal body weight in kilograms.     

The cytologic and histologic diagnosis of ureteral fibroepithelial polyp in a dog

A 6-year-old, intact male, brindled, 30-Lb English Bulldog presented to the Purdue University Veterinary Teaching Hospital with a recurrent history of hematuria, periuria, and lethargy that responded temporarily to antibiotic therapy. The work-up included a complete blood count, serum biochemical profile, complete urinalysis, diagnostic imaging (abdominal radiographs and ultrasound with contrast urography), and exploratory laparotomy. The diagnostic imaging findings and subsequent exploratory revealed a unilateral, intraluminal, right-sided, 3-cm ureteral mass extending from the proximal ureter into the renal pelvis. Subsequently, a unilateral right-sided ureteronephrectomy followed by biopsy with cytopathology/cytology (impression smears) and histopathology of the ureteral mass was performed. The cytopathologic interpretation was benign mesenchymal proliferation with mildly atypical urothelial cells. The association of this mass with vascular tissue and a benign nuclear appearance on cytology is similar to reports of fibroepithelial polyps (FEPs) and myxomatous tumors. Histopathology diagnosed the mass as an FEP. Cytopathology proved useful in the presumptive diagnosis of this benign urothelial polyp. To the authors' knowledge, this is the first report using cytopathology to depict and characterize FEPs in veterinary and human medical literature.     

Comparative efficacy of tulathromycin, tilmicosin, and florfenicol in the treatment of bovine respiratory disease in stocker cattle

The therapeutic efficacy and field safety of tulathromycin were evaluated in stocker calves with undifferentiated bovine respiratory disease (BRD) in three field studies conducted over two consecutive grazing seasons in Nebraska. Eight hundred calves exhibiting clinical signs of BRD and with rectal temperatures of 104 degrees F or higher were treated with tulathromycin (n = 340), florfenicol (n = 240), or tilmicosin (n = 220) and evaluated for approximately 60 days. Florfenicol and tilmicosin were administered as single SC injections according to labeled dosage. Tulathromycin was administered as a single SC injection of 2.5 mg/kg. In all three studies, the cure rate of calves 60 days after treatment with tulathromycin was significantly higher (P < or = .05) than that of calves treated with florfenicol or tilmicosin. Suspected adverse reactions were not reported for any of the study drugs. Tulathromycin proved to be significantly more effective than either florfenicol or tilmicosin in the treatment of BRD in stocker calves.