Immunology of Inflammatory Diseases of the Bowel

Evaluation of pastures for horses grazing on soils polluted by trace elements

Pasture established on polluted soil may pose a risk to grazing livestock creating a requirement for mechanical management which may affect biodiversity and expend energy. The risk associated with managing pasture by grazing horses (non-edible livestock) is being assessed in the Guadiamar Valley (SW Spain), where soils are polluted with trace elements following a major pollution incident. Soil pollution does not affect biomass production or floristic composition of pasture, although both variables influence trace element accumulation in herbage. Element concentrations in herbage are below maximum tolerable limits for horses. Faecal analysis showed regulated absorption of essential elements, while non-essential elements seemed preferentially excreted. Elemental content of horse hair did not differ in animals from polluted and control pastures. If pastures are managed by grazing, periodic monitoring is recommended in view of the long-term chronic trace element exposure in these systems.

The association of sub-clinical paratuberculosis with the fertility of Greek dairy ewes and goats varies with parity

Our cross-sectional study investigated the association of sub-clinical Mycobacterium avium subsp. paratuberculosis (MAP) infection with failing to produce a live offspring the season of lambing/kidding (November 2001 to January 2002) before testing (in April-May 2002), in four dairy-sheep and/or goat flocks in Greece (369 animals >or=1.5-year-old). From each selected animal 10 ml of blood and 10 g of feces from the rectum were obtained. The harvested sera were tested for antibodies to MAP with a commercial ELISA test kit; the feces were cultured on Herrold's egg-yolk medium supplemented with mycobactin J and antibiotics. An animal was considered sub-clinically infected when found either seropositive or culture positive. The true prevalence of sub-clinically infected animals, adjusted for the sensitivity and specificity of the parallel testing, was 14% (0.1-28%) and 35.9% (9.2-62.7%) in sheep and goats, respectively. The association of fertility of sheep and goats with sub-clinical paratuberculosis was investigated in random-effects logistic models. Sub-clinically infected animals (compared to uninfected) had OR for live offspring the previous year of 5.4 for parity <4, OR=0.05 for parity >6, and a non-significant OR for the middle parity category.