Mucosal distribution of eosinophilic granulocytes within the gastrointestinal tract of horses

OBJECTIVES: To establish reference values for the range of the number of eosinophils found in equine gastrointestinal mucosa and to describe the distribution of this cell within the equine gastrointestinal mucosa. SAMPLE POPULATION: Gastrointestinal mucosal specimens from 14 adult horses euthanatized for reasons other than gastrointestinal disease. PROCEDURES: Gastrointestinal mucosal specimens were collected and grouped according to their anatomic regions. For histologic examination slides were stained with Luna's eosinophil stain to determine eosinophil accumulation and distribution. The mucosa was divided into 5 sections for each anatomic location, and the percentage of eosinophils in each of the 5 sections relative to the total eosinophil count in all sections was determined. Additionally, the number of eosinophils per square millimeter of mucosa was calculated as a measure of the degree of eosinophil accumulation. RESULTS: Lowest numbers of eosinophils were found in the stomach, and numbers increased from there to the cecum, then decreased from the ascending colon (right ventral colon, left ventral colon, pelvic flexure, left dorsal colon, and right dorsal colon) to small colon. In all gastrointestinal sections, most eosinophils were located near the muscularis mucosae and were rarely found near or on the luminal surface of the mucosa. CONCLUSIONS AND CLINICAL RELEVANCE: The distribution of eosinophils in the gastrointestinal tract of horses followed a pattern within the mucosa and between different sections of the gastrointestinal tract. The derived reference values and distribution data could be used to detect changes in eosinophil response in the equine gastrointestinal mucosa caused by diseases states.     

Practical Challenges in Private Stewardship of Rangeland Ecosystems: Yellow Starthistle Control in Sierra Nevadan Foothills

Private landowners are often de facto stewards of biodiversity and ecosystem services. In California's Sierra Nevada foothills, ranchers frequently present the only defense against biological invasions in private rangelands. Although ranchers' land management goals (e.g., the desire to control invasive species) can be consistent with ecosystem protection, practical constraints often limit their success. Considerable research on the invasive weed, yellow starthistle (Centaurea solstitialis L.), has produced numerous control strategies. Nevertheless, the range of this noxious weed continues to increase. We used surveys and interviews to document the weed control efforts of 202 ranchers and to identify practical limitations to their efficacy. Overall, 86% of ranchers who had experienced yellow starthistle infestation had attempted control, using one or more of 19 methods. Early response reduced negative effects from yellow starthistle. Control methods learned from agricultural advisors were reported more effective than those learned elsewhere. Limitations to yellow starthistle control in our study population resulted from incomplete information regarding control methods, complexity of weed control in heterogeneous landscapes, inconsistent application of methods, and lack of long-term planning for weed control. Such hindrances make it difficult for landowners to implement control methods promoted by researchers. This gap between science and practice contributes to the continued increase of yellow starthistle within the study region. To shrink this gap, researchers and agricultural advisors can incorporate environmental heterogeneity into applied agricultural research, use land stewards' knowledge and experience, and increase public education.     

Geographical isolation of native sheep breeds in the UK—Evidence of endemism as a risk factor to genetic resources

This study addresses the potential risk to the genetic resources of UK sheep breeds from endemism. Twelve native breeds are analysed that exist in significant numbers and continue to be commercially farmed livestock. The breeds were selected to represent regions of the British Isles: North of England hill breeds (Herdwick, Rough Fell, Lonk, Dalesbred), South of England breeds (Southdown, Romney, Devon Closewool, Exmoor Horn), Scottish breed (South Country Cheviot) and Welsh/Welsh border breeds (Welsh Hill Speckled Face, South Wales Mountain (Nelson), Clun Forest).For each breed, numerical data were collected in collaboration with breed society members and analysed in terms of population size and structure together with the extent of their geographical range. The number of flocks per breed proved to be highly variable, questioning the assumption that has been made that the number of breeding units can be disregarded in the calculations of endangerment. The data also indicated that an average flock size for a breed cannot be estimated to gain an insight of the population structure, since this parameter was found to vary considerably within and between breeds. The endemism was best illustrated in the breed maps which clearly highlighted the degree to which each breed was associated with a distinct geographical area. From the maps, ten of the twelve breeds analysed were concentrated, but the flocks of two breeds were visually more dispersed. In numerical terms, the ten breeds were found to have up to 95% of their breed numbers concentrated within a radius of 65 km from the mean centre of each breed.The study provides a valuable foundation for future research into genetic diversity within and between the sheep breeds analysed, a baseline of information to enable population trends to be examined and a robust evidence-base for policy decisions on Farm Animal Genetic Resources (FAnGR).     

Comparison of two DNA extractions and nested PCR, real-time PCR, a new commercial PCR assay, and bacterial culture for detection of Mycobacterium avium subsp. paratuberculosis in bovine feces.

In this study, 5 combinations of 2 DNA extractions and 3 polymerase chain reaction (PCR) techniques were compared with culture for the detection of Mycobacterium paratuberculosis directly from bovine feces. These combinations included a new commercial extraction technique combined with a commercial PCR/Southern blot technique, nested PCR (nPCR), or real-time PCR, and a university-developed extraction combined with nPCR or real-time PCR. Four of the 5 combinations had statistically similar sensitivities between 93% and 100% and specificity between 95% and 100%, when compared with culture results from 63 bovine fecal samples. These results indicated that using a commercial extraction with a commercial PCR/Southern blot, nPCR, or real-time PCR, or a university-developed extraction with real-time PCR would result in similar sensitivities to culture for the identification of M. paratuberculosis from bovine feces and are valid alternatives to culture.     

Lead contamination of chicken eggs and tissues from a small farm flock.

Twenty mixed-breed adult laying hens from a small farm flock in Iowa were clinically normal but had been exposed to chips of lead-based paint in their environment. These chickens were brought to the Iowa State University Veterinary Diagnostic Laboratory, Ames, Iowa, where the concentration of lead in blood, eggs (yolk, albumen, and shell), and tissues (liver, kidney, muscle, and ovary) from 5 selected chickens was determined over a period of 9 days. Blood lead levels ranged from less than 50 to 760 ppb. Lead contamination of the yolks varied from less than 20 to 400 ppb, and shells were found to contain up to 450 ppb lead. Albumen contained no detectable amount. Lead content of the egg yolks strongly correlated with blood lead levels. Deposition of lead in the shells did not correlate well with blood lead levels. Mean tissue lead accumulation was highest in kidneys (1,360 ppb), with livers ranking second (500 ppb) and ovarian tissue third (320 ppb). Muscle contained the lowest level of lead (280 ppb). Lead contamination of egg yolks and edible chicken tissues represents a potential public health hazard, especially to children repeatedly consuming eggs from contaminated family-owned flocks.     

Effects of acute hyperinsulinemia on inflammatory proteins in horses

Laminitis is a painful, inflammatory disease of the equine hoof that often results in euthanasia. Elevated plasma insulin concentrations are a predictive factor for laminitis, and in previously healthy horses and ponies, laminitis was induced by infusion of insulin. Thus, we chose to determine if an infusion of insulin would increase plasma concentrations of inflammatory cytokines and cytokine mRNA abundance in subcutaneous adipose tissue, skeletal muscle, and white blood cells. Ten mature Thoroughbred mares received an insulin infusion that elevated plasma insulin concentrations for 6h or an equivalent volume of isotonic saline in a switchback design. Insulin infusion altered plasma concentrations of both TNF (P=0.037) and IL-6 (P=0.044), but did not result in consistent changes to either skeletal muscle or adipose tissue cytokine mRNA. Insulin may be involved in the production of inflammatory cytokines, and this could be a mechanism for insulin increasing the risk of laminitis.