Short-term exposure to subacute doses of aflatoxin-induced depressed mitogen responses in young mallard ducks     

Hurley DJ  Neiger RD  Higgins KF  Rottinghaus GE  Stahr H 《Avian diseases》1999,43(4):649-655

Mallard ducklings were fed diets containing corn naturally contaminated with mixed aflatoxins, purified T-2 toxin, or no detectable mycotoxin in two trials. The aflatoxin level used was 12 ppb in the first trial and 33 ppb in the second. T-2 was added at 2 ppm in both trials. No pathology was associated with the aflatoxin used in this study, and T-2--induced lesions were described in a previous publication. The weights of primary (thymus and bursa of Fabricius) and secondary (spleen) lymphoid organs were significantly reduced in the T-2--treated birds. The total number of viable cells recovered from the thymus was significantly reduced in aflatoxin-treated birds. The numbers of viable cells recovered from thymus, bursa of Fabricius, and spleen were all significantly reduced after treatment with T-2. In each trial, significantly lower mitogenic responses were seen to pokeweed mitogen and concanavalin A in birds fed aflatoxin or T-2, representing reduction in both B-cell and T-cell mitogenesis. Birds fed aflatoxin also had significantly reduced Escherichia coli O55 lipopolysaccharide-induced mitogenic responses. These studies indicate that subacute oral exposure to aflatoxin caused a loss of normal lymphocyte reactivity in mallard ducklings. This finding supports the hypothesis that waterfowl that ingest even small quantities of mycotoxin-contaminated waste grain are likely to be more susceptible to bacterial or viral infections.  相似文献   

Behavioral, nutritional, and toxicological responses of cattle to ensiled leafy spurge     

Heemstra JM  Kronberg SL  Neiger RD  Pruitt RJ 《Journal of animal science》1999,77(3):600-610

Yearling cattle (n = 25; 416.1 +/- 25.9 kg) were stratified by weight and gender across five groups. Group 1 (OAT) was offered oat/rape haylage (ORH) for ad libitum consumption during two daily feeding periods. Group 2 (SPURGE) was offered leafy spurge/grass haylage (LSGH) for ad libitum consumption during the same feeding periods. Group 3 was offered ORH in an amount equal to the average amount of LSGH consumed by SPURGE at the previous feeding. Group 4 (MIX) was offered LSGH mixed with ORH for ad libitum consumption during the two feeding periods. Group 5 (PAIR) received the equivalent amount of ORH consumed by MIX at the previous feeding. The DMI for OAT, SPURGE, and MIX were similar at the first feeding (P = .52). The SPURGE group consumed very little LSGH thereafter and was removed from the trial. The OAT and MIX groups consumed similar amounts of DM daily on d 1 to 4 when the ration offered to MIX was only 7% LSGH (P = .33). When LSGH made up > or = 21% of the mixture (d 7 to 32), the OAT group consumed more daily DM than did MIX (P < .05). The spurge/oatlage ration offered to MIX was less digestible than the oatlage-only ration offered to PAIR (P < or = .01). Even though blood chemistry did not indicate that LSGH consumption caused organ damage, its intake caused minor alterations (P < or = .05) in serum albumin, calcium, gamma glutamyltransferase, P, K, and urea nitrogen. No gross or microscopic lesions, infectious agents, or significant numbers of parasites were detected in any of the carcasses or tissues examined. The MIX group had diarrhea for much of the trial. In Trial 2, five yearling cattle were adapted to a mixture of 21% LSGH and 79% ORH. Then they were simultaneously offered three mixtures of spurge and oat haylages: 1) spurge ensiled with a microbial inoculant (LSGH); 2) spurge ensiled with the same inoculant and a cellulolytic/hemicellulolytic enzyme (ENZ); and 3) spurge ensiled with the same inoculant and molasses (MOL). The mixture with ENZ was preferred over those with MOL or LSGH (P < .001), but the amounts consumed were low and similar to those for LSGH-ORH in Trial 1 when amounts of ENZ and LSGH in the mixtures were similar. The ENZ mixture may have been more palatable than LSGH and MOL because it had less (P < .05) lactic acid, but intake of ENZ indicates that it had aversive characteristics, like LSGH. Ensiling leafy spurge did little, if anything, to improve its palatability to cattle.  相似文献   

Comparison of postprandial and ceruletide serum bile acid stimulation in dogs     

Bridger N  Glanemann B  Neiger R 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2008,22(4):873-878

BACKGROUND: Postprandial (PP) serum bile acid (SBA) stimulation is an important test for detecting hepatic dysfunction in dogs. However, this test is influenced by numerous variables, and a standardized approach using an injectable cholecystokinin analog (ceruletide) may be advantageous. HYPOTHESIS: Ceruletide SBA stimulation test is more sensitive than PP SBA stimulation in dogs. ANIMALS: Animals with portosystemic shunt (PSS) (n = 11) and dogs with upper respiratory disease (URD) (n = 9) were investigated. Healthy dogs (n = 13) and dogs with other diseases (n = 17) served as controls. METHODS: All dogs underwent SBA stimulation with food and ceruletide. Stimulation blood samples were drawn at 60/120 minutes and 20/30/40 minutes, respectively. Results were compared statistically, and the sensitivity and specificity were determined with receiver-operating characteristic curves. RESULTS: Stimulated SBA were significantly higher in both study groups than in controls. For dogs with PSS, the sensitivity and specificity (>35 micromol/L) were 100% postprandially (120 minutes) and 91 and 100%, respectively, postceruletide (30 minutes). The difference between these values was not statistically significant. For dogs with URD, the sensitivity and specificity (>22 micromol/L) were 44 and 88% postprandially (120 minutes) and 100 and 88% postceruletide (30 minutes). CONCLUSIONS AND CLINICAL IMPORTANCE: Ceruletide SBA stimulation circumvents exogenous and endogenous influences associated with PP SBA stimulation. The results indicate that ceruletide SBA stimulation performs as well as PP SBA stimulation in dogs with PSS and is more sensitive for the detection of hepatic dysfunction in dogs with URD.  相似文献   

Adrenal necrosis in a dog receiving trilostane for the treatment of hyperadrenocorticism     

Chapman PS  Kelly DF  Archer J  Brockman DJ  Neiger R 《The Journal of small animal practice》2004,45(6):307-310

Clinical and biochemical changes suggestive of hypoadrenocorticism were observed in a 10-year-old male neutered Staffordshire bull terrier shortly after beginning therapy with trilostane for the treatment of hyperadrenocorticism. The dog's condition was stabilised with intravenous fluids, fludrocortisone and prednisolone. An exploratory laparotomy and excisional biopsy of the left adrenal gland were performed. Histopathological analysis showed adrenal cortical necrosis with reactive inflammation and fibrosis. Trilostane is a reversible inhibitor of steroid synthesis and this complication has not been reported previously. Clinicians should be aware that trilostane therapy may result in adrenal necrosis but that prompt treatment might correct a life-threatening situation.  相似文献   

Attaching and effacing Escherichia coli infection as a cause of diarrhea in young calves   总被引：6，自引：0，他引：6  

B H Janke  D H Francis  J E Collins  M C Libal  D H Zeman  D D Johnson  R D Neiger 《Journal of the American Veterinary Medical Association》1990,196(6):897-901

A form of enteric Escherichia coli infection was identified in 60 calves from 59 farming operations. The E coli responsible for these infections principally colonized the colon, inducing a distinctive lesion described as attaching and effacing. Hemorrhagic enterocolitis or blood in the feces was observed on 40% of the farms. Of affected calves, 86.6% were dairy calves (average age, 11.8 days). Forty-four calves were infected concurrently with other enteropathogens (cryptosporidia, rotavirus, coronavirus, enterotoxigenic E coli, bovine viral diarrhea virus, coccidia). Verotoxin-producing E coli was recovered from 31 calves; 8 were serotype O111:NM isolates, 3 were serotype O5:NM, and 1 was serotype O26:NM.  相似文献   

Spatial sensitivity of species habitat patterns to scenarios of land use change (Switzerland)   总被引：3，自引：2，他引：3  

Janine Bolliger  Felix Kienast  Reto Soliva  Gillian Rutherford 《Landscape Ecology》2007,22(5):773-789

Long-term societal trends which include decreasing population in structurally poorer regions and changes in agricultural policies have been leading to land abandonment in various regions of Europe. One of the consequences of this development includes spontaneous forest regeneration of formerly open-land habitats with likely significant effects on plant and animal diversity. We assess potential effects of agricultural decline in Switzerland (41,000 km²) and potential impacts on the spatial distribution of seven open-land species (insects, reptile, birds) under land-use change scenarios: (1) a business-as-usual scenario that extrapolates trends observed during the last 15 years into the future, (2) a liberalisation scenario with limited regulation, and (3) a lowered agricultural production scenario fostering conservation. All scenarios were developed in collaboration with socio-economists. Results show that spontaneous reforestation is potentially minor in the lowlands since combinations of socio-economic (better accessibility), topographic (less steep slopes), and climatic factors (longer growing seasons) favour agricultural use and make land abandonment less likely. Land abandonment, spontaneous reforestation, and subsequent loss of open-land, however, are potentially pronounced in mountainous areas except where tourism is a major source of income. Here, socio-economic and natural conditions for cultivation are more difficult, leading to higher abandonment and thus reforestation likelihood. Evaluations for open-land species core habitats indicate pronounced spatial segregation of expected landscape change. Habitat losses (up to 59%) are observed throughout the country, particularly at high elevation sites in the Northern Alps. Habitat gains under the lowered agricultural production scenario range between 12 and 41% and are primarily observed for the Plateau and the Northern Alps.  相似文献   

Effect of Trilostane on Hormone and Serum Electrolyte Concentrations in Dogs with Pituitary‐Dependent Hyperadrenocorticism     

C. Griebsch  C. Lehnert  G.J. Williams  K. Failing  R. Neiger 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2014,28(1):160-165

Background

The effects of trilostane on key hormones and electrolytes over 24 hours in dogs with pituitary‐dependent hyperadrenocorticism (PDH) are unknown.

Objectives

To determine the plasma concentration of cortisol, endogenous adrenocorticotropic hormone (ACTH), aldosterone, sodium, potassium, and ionized calcium concentrations, and plasma renin activity over a 24‐hour period after administration of trilostane to dogs with well‐controlled PDH.

Animals

Nine dogs (mean age 9.3 ± 0.67 years, mean weight 31.9 ± 6.4 kg) with confirmed PDH.

Methods

Prospective study. Thirty days after the first administration of trilostane, blood samples were taken at −30, 0 (baseline), 15, 30, 60, and 90 minutes, and 2, 3, 4, 6, 8, 12, 16, 20, and 24 hours after administration of trilostane and plasma concentration of cortisol, endogenous ACTH, aldosterone, sodium, potassium, ionized calcium, and renin activity were determined.

Results

Cortisol concentrations decreased significantly (P < .001) 2–4 hours after trilostane administration. From baseline, there was a significant (P < .001) increase in endogenous ACTH concentrations between hours 3–12, a significant increase (P < .001) in aldosterone concentration between hours 16–20, and a significant (P < .001) increase in renin activity between hours 6–20. Potassium concentration decreased significantly (P < .05) between hours 0.5–2.

Conclusion and Clinical Importance

Treatment with trilostane did not cause clinically relevant alterations in plasma aldosterone and potassium concentration. Results suggest that in dogs with PDH, the optimal time point for an ACTH‐stimulation test to be performed is 2–4 hours after trilostane dosing. Future studies are necessary to establish interpretation criteria for a 2‐ to 4‐hour postpill ACTH‐stimulation test.  相似文献   

Persistent infections after natural transmission of bovine viral diarrhoea virus from cattle to goats and among goats     

Claudia Bachofen  Hans-Rudolf Vogt  Hanspeter Stalder  Tanja Mathys  Reto Zanoni  Monika Hilbe  Matthias Schweizer  Ernst Peterhans 《Veterinary research》2013,44(1):32

Bovine viral diarrhoea virus (BVDV) is an economically important pathogen of cattle worldwide. Infection of a pregnant animal may lead to persistent infection of the foetus and birth of a persistently infected (PI) calf that sheds the virus throughout its life. However, BVD viruses are not strictly species specific. BVDV has been isolated from many domesticated and wild ruminants. This is of practical importance as virus reservoirs in non-bovine hosts may hamper BVDV control in cattle. A goat given as a social companion to a BVDV PI calf gave birth to a PI goat kid. In order to test if goat to goat infections were possible, seronegative pregnant goats were exposed to the PI goat. In parallel, seronegative pregnant goats were kept together with the PI calf. Only the goat to goat transmission resulted in the birth of a next generation of BVDV PI kids whereas all goats kept together with the PI calf aborted. To our knowledge, this is the first report which shows that a PI goat cannot only transmit BVD virus to other goats but that such transmission may indeed lead to the birth of a second generation of PI goats. Genetic analyses indicated that establishment in the new host species may be associated with step-wise adaptations in the viral genome. Thus, goats have the potential to be a reservoir for BVDV. However, the PI goats showed growth retardation and anaemia and their survival under natural conditions remains questionable.  相似文献   

Breakdown of cortical effective connectivity during sleep     

Massimini M  Ferrarelli F  Huber R  Esser SK  Singh H  Tononi G 《Science (New York, N.Y.)》2005,309(5744):2228-2232

When we fall asleep, consciousness fades yet the brain remains active. Why is this so? To investigate whether changes in cortical information transmission play a role, we used transcranial magnetic stimulation together with high-density electroencephalography and asked how the activation of one cortical area (the premotor area) is transmitted to the rest of the brain. During quiet wakefulness, an initial response (approximately 15 milliseconds) at the stimulation site was followed by a sequence of waves that moved to connected cortical areas several centimeters away. During non-rapid eye movement sleep, the initial response was stronger but was rapidly extinguished and did not propagate beyond the stimulation site. Thus, the fading of consciousness during certain stages of sleep may be related to a breakdown in cortical effective connectivity.  相似文献   

RADIOLOGY CORNER DIFFERENTIAL DIAGNOSIS OF PULMONARY CAVITARY LESIONS     

Christopher R.  Lamb  Reto  Neiger 《Veterinary radiology & ultrasound》2000,41(4):340-341

  相似文献