Intracerebroventricular Infusion of Leptin into Mature Merino Rams of Different Metabolic Status: Effects on Blood Concentrations of Glucose and Reproductive and Metabolic Hormones

In mature Merino rams, nutrition is one of the external cues that most strongly affects the reproductive centres of the preoptic-hypothalamic continuum. The signalling pathways that link dietary status and the activity of the neurones that produce gonadotrophin-releasing hormone signals are thought to be partly hormonal in nature to reflect the amount of body reserves. Among the hormones thought to be involved are insulin and leptin. This study tested whether recombinant bovine leptin infused (0.4 microg/h) into the third cerebral ventricle would stimulate pulsatile luteinizing hormone (LH) secretion in mature Merino rams when their energy status was low or decreasing, during both chronic (fasting) and acute reductions of energy balance. Leptin may interact with other hormones that depend on energy availability, so we also monitored changes in circulating concentrations of insulin, thyroid hormones, growth hormone, prolactin and adrenocorticotrophin. Overall, our data do not support this hypothesis. The dietary regimes induced clear responses in the metabolic profiles of the animals but there was no clear effect of central leptin administration on LH pulse frequency. The relationships between the hormonal systems measured in the present study add weight to the contention that leptin plays only a permissive role in the nutritional control of the reproductive axis and that other hormonal signals (particularly insulin) or pathways are acting in concert with leptin to stimulate the reproductive axis.     

Leukocytic responses and intestinal mucin dynamics of broilers protected with Enterococcus faecium EF55 and challenged with Salmonella Enteritidis

The protective effect of Enterococcus faecium EF55 in chickens challenged with Salmonella enterica serovar Enteritidis phage type 4 (SE PT4) was assessed. The antibacterial effect on the bacterial microflora in the small intestine in relation to white blood cell count, phenotyping of peripheral blood and intestinal lymphocytes, functional activity of lymphocytes and phagocytes and mucin quantitation were investigated. Day-old chicks (85) were randomly divided into four groups. The probiotic group (EF) and Salmonella + probiotic group (EFSE) received E. faecium EF55 (10⁹ CFU – 3 g/group/day) for 21 days. The Salmonella group (SE) and EFSE group were infected with Salmonella Enteritidis (10⁸ CFU in 0.2 ml PBS) in a single dose per os on day four of the experiment. The control group chicks (C) were fed a commercial diet without added bacteria. Supplementation of EF55 in the diet of the chickens in the EFSE group, challenged with S. Enteritidis, caused the density of the intestinal mucin layer to increase significantly in non-specific regions (duodenum and jejunum), but decrease significantly in target regions (caeca) for S. Enteritidis. Probiotic treatment also appeared to result in a significantly higher number of lymphocytes in peripheral blood and a tendency to increase CD3, CD4, CD8, and IgM positive cells 3 days post-infection with S. Enteritidis. The results demonstrated an antibacterial effect and suggested that EF55 had a moderating effect on intestinal mucin production and leukocytic response in the early phase of S. Enteritidis infection.     

Outcomes of 35 dogs with craniomaxillofacial osteosarcoma treated with stereotactic body radiation therapy

Canine craniomaxillofacial osteosarcoma (OSA) is most commonly treated surgically; however, in cases where surgery is not feasible or non-invasive treatment is desired, stereotactic body radiation therapy (SBRT) may be elected for local tumour control. In this study, we evaluated 35 dogs treated with SBRT. Nine dogs (26%) had calvarial, seven (20%) had mandibular and 19 (54%) had maxillary OSA. Median time to first event (TFE) was 171 days, and overall median survival time (MST) was 232 days. Site-specific MSTs were 144 days for mandible, 236 days for calvarium and 232 days for maxilla (p = .49). Pulmonary metastatic disease was observed in 12/35 (34%) patients and was detected pre-SBRT in six dogs (17%) and post-SBRT in the remaining six dogs (17%). Eighteen adverse events post-SBRT were documented. Per veterinary radiation therapy oncology group criteria, five were acute (14%) and three were late (9%) grade 3 events. Neurological signs in two dogs were suspected to be early-delayed effects. Cause of death was local progression for 22/35 (63%) patients, metastasis for 9/35 (26%) patients and unknown for four. On univariate analysis, administration of chemotherapy was associated with a longer TFE (p = .0163), whereas volume of gross tumour volume was associated with a shorter TFE (p = .023). Administration of chemotherapy and five fractions versus single fraction of SBRT was associated with increased survival time (p = .0021 and .049). Based on these findings, a treatment protocol incorporating chemotherapy and five fractions of SBRT could be considered for dogs with craniomaxillofacial OSA electing SBRT with careful consideration of normal tissues in the field.     

Transthoracic echocardiographic measurement of patent ductus arteriosus in dogs

BACKGROUND: Patent ductus arteriosus (PDA) size and morphology influence the selection of the kind and the size of the embolization device used to effect shunt closure. HYPOTHESIS: That echocardiographic measurement of PDA in dogs is accurate. ANIMALS: Forty-five client-owned dogs with PDA. METHODS: Prospective observational study. Echocardiographic and angiographic data were compared. RESULTS: Measurement of the ductus in color Doppler echocardiography (CD-E) and 2-dimensional echocardiography (2D-E) was achieved from left parasternal views in 43 of 45 unsedated dogs (96%). In these 43 dogs, the angiographic minimal PDA diameter was 3.72 +/- 1.59 mm, and the diameter of the PDA ampulla was 8.46 +/- 3.01 mm. The CD-E minimal PDA diameter ranged from 2.3 to 9.5 mm (median, 4.0 mm). There was a significant mean difference to the angiographic measurements (1.15 +/- 0.95 mm; P < .0001). An agreement in a 1-mm range was found in 21 of 43 dogs (48%). The 2D-E minimal PDA diameter was 3.73 +/- 1.78 mm, and the mean difference to the angiographic measurements was not significant (0.00 +/- 0.72 mm; P = .98). An agreement in a 1-mm range was found in 31 of 43 dogs (72%). The 2D-E measurement of the PDA ampulla revealed a significant mean difference to the angiographic data (1.95 +/- 2.43 mm, P < .0001). An agreement in a 2-mm range was found in 21 of 43 dogs (49%). CONCLUSIONS AND CLINICAL IMPORTANCE: The 2D-E from the left cranial parasternal view is an excellent noninvasive method to estimate the PDA minimal diameter before doing catheter intervention.     

Urinary catecholamine and metanephrine to creatinine ratios in healthy dogs at home and in a hospital environment and in 2 dogs with pheochromocytoma

BACKGROUND: Measurement of high concentrations of urine catecholamines and metanephrines is useful in diagnosing pheochromocytoma in humans. Stress increases catecholamine excretion in urine. HYPOTHESIS: Stress of a hospital visit increases urinary catecholamine and metanephrine excretion in dogs. ANIMALS: Fourteen clinically normal dogs, 2 dogs with pheochromocytoma. METHODS: Voided urine samples were collected by the owners 7 days before (t-7), during the hospital visit immediately after diagnostic procedures (t0), as well as 1 (t1) and 7 days (t7) after the hospital visit. Urine catecholamine and metanephrine concentrations were measured using high-pressure liquid chromatography and expressed as ratios to urine creatinine concentration. RESULTS: In client-owned dogs epinephrine and norepinephrine ratios at t0 were significantly higher compared with ratios at t7. Metanephrine and normetanephrine ratios at t-7, t0, and t1 did not differ significantly from each other; however, at t7 they were significantly lower compared to values at t-7. In staff-owned dogs no significant differences were detected among the different collecting time points for any variable. Metanephrine and normetanephrine ratios were significantly higher in client-owned dogs compared to staff-owned dogs at t-7, t0, and t1 but not at t7. CONCLUSIONS AND CLINICAL IMPORTANCE: Stress associated with a hospital visit and with the sampling procedure causes increases in urine catecholamine and metanephrine excretion. Urine collection for the diagnosis of pheochromocytoma probably should take place at home after adaptation to the sampling procedure.     

Demonstrating freedom from disease using multiple complex data sources 2: case study--classical swine fever in Denmark

A method for quantitative evaluation of surveillance for disease freedom has been presented in the accompanying paper (Martin et al., 2007). This paper presents an application of the methods, using as an example surveillance for classical swine fever (CSF) in Denmark in 2005. A scenario tree model is presented for the abattoir-based serology component of the Danish CSF surveillance system, in which blood samples are collected in an ad hoc abattoir sampling process, from adult pigs originating in breeding herds in Denmark. The model incorporates effects of targeting (differential risk of seropositivity) associated with age and location (county), and disease clustering within herds. A surveillance time period of one month was used in the analysis. Records for the year 2005 were analysed, representing 25,332 samples from 3528 herds; all were negative for CSF-specific antibodies. Design prevalences of 0.1-1% of herds and 5% of animals within an infected herd were used. The estimated mean surveillance system component (SSC) sensitivities (probability that the SSC would give a positive outcome given the animals processed and that the country is infected at the design prevalences) per month were 0.18, 0.63 and 0.86, for among-herd design prevalences of 0.001, 0.005 and 0.01. The probabilities that the population was free from CSF at each of these design prevalences, after a year of accumulated negative surveillance data, were 0.91, 1.00 and 1.00. Targeting adults and herds from South Jutland was estimated to give approximately 1.9, 1.6 and 1.4 times the surveillance sensitivity of a proportionally representative sampling program for these three among-herd design prevalences.     

A comparative description of two farmer-managed irrigation systems in Nepal

The organization of two farmer-managed irrigation systems in the western hills of Nepal is described by examining the ways in which the activities of water allocation, water distribution, maintenance, and resource mobilization are performed. Due to the topography and environment, these two organizations are structured primarily to mobilize the large amount of labor required for maintenance of the intake and canal. Both organizations precisely define each member's water allocation. In one system, water is allocated in proportion to the area of an individual's land holding, while in the other water allocation is by purchased shares. These two cases were used to analyze the importance of the principle of water allocation for expansion of area irrigated and equity of access to irrigation. Evidence from the two systems shows that in this hill environment water allocation by purchased shares provides the individual incentive and an organizational mechanism for efficient development of irrigation resources. Expansion of area irrigated and equity of access to irrigation were found to be greater in the system which allocates water by purchased shares than where water was allocated in proportion to area irrigated.