Flock health survey of Irish Texel society breeders and larynx examination in Texel sheep.

BACKGROUND: Laryngeal chondritis is a disease of undetermined aetiology, characterised by oedema, ulceration, abscessation and necrosis of the laryngeal mucosa and cartilage. The initial aim of the study was to document flock health issues identified by Irish pedigree Texel breeders using a questionnaire survey. Additionally, given the reports of breed predisposition for laryngeal chondritis in Texels, a further aim was to identify if laryngeal problems were perceived as an issue. Work was then conducted to identify if pre-clinical laryngeal mucosal pathology was identifiable in Texel sheep showing no overt clinical signs of respiratory disease and if associations existed between laryngeal measurements and laryngeal pathology.Thirty one larynges were collected from a Texel flock that previously had laryngeal chondritis diagnosed in fallen stock. Gross visual inspection was performed to identify and grade (0-5) laryngeal pathology. A series of measurements were then performed on larynges that had been formalin fixed. Associations between independent variables (larynx measurements) and the dependent variable (laryngeal pathology score) were examined. RESULTS: Respiratory disease was the most frequently identified health issue. Farmer-diagnosed 'throat problems' were reported by over 80% of respondents.Laryngeal pathology was noted in Texels showing no overt clinical signs of respiratory disease. Associations between laryngeal measurements and laryngeal pathology were identified relating to the angle between the cranial point of the cricoid cartilage and the vocal process of the arytenoid cartilage. CONCLUSIONS: Mild laryngeal pathology was noted in animals with no overt clinical signs of respiratory disease. Future research should examine whether significant associations between laryngeal measurements and laryngeal pathology identified in the current study can be measured ante mortem, and whether such ante mortem measurements will allow early identification of sheep at risk of developing laryngeal chondritis.

Descriptive analysis of ovine mortality in sentinel sheep flocks in Ireland.

BACKGROUND: Studies of sheep mortality or cause-specific mortality, in Ireland or internationally, are relatively scarce but are important in presenting baseline levels and changing trends of endemic disease. This study assessed sheep mortality and cause-specific mortality in 33 sentinel sheep flocks in Ireland. METHODS: Sentinel flocks were requested to submit carcases of all sheep that died to the regional veterinary laboratories (RVLs) of the Department of Agriculture, Food and Marine during a calendar year (2016). Postmortem examinations were performed on 1247 submissions to Athlone, Kilkenny and Sligo RVLs. RESULTS: The median overall submission rate was 13.8 per cent (range 2.5 per cent-35.8 per cent) per adult female sheep in the flock in January 2016. The median fetal, perinatal, lamb and adult submissions per adult female sheep in the flock in January 2016 were 2.1 per cent (0.0 per cent-15.2 per cent), 3.5 per cent (0.0 per cent-20.0 per cent), 3.0 per cent (0.0 per cent-12.4 per cent) and 2.8 per cent (0.8 per cent-7.1 per cent), respectively. The frequency of detection of categories of postmortem diagnoses in fetuses, perinates, lambs and adults are presented. CONCLUSIONS: Comparisons with existing passive surveillance findings reflect some differences in the relative frequency of detection of certain categories of disease suggesting that sentinel flock surveillance could usefully supplement existing passive animal disease surveillance activities for ovine disease.

Epidemiological investigation of a severe rumen fluke outbreak on an Irish dairy farm.

Although the rumen fluke, Calicophoron daubneyi is now very common and widespread throughout Western Europe, reports of clinical cases are still rare. This study explores the epidemiological background to a severe rumen fluke outbreak in 6-month-old heifers on a dairy farm in Ireland. Sequence analysis of the cytochrome oxidase subunit 1 (Cox1) gene of the rumen fluke metacercariae on pasture failed to identify predominant, possibly pathogenic subtypes. However, estimates of metacercarial load indicated that the animals were exposed to a daily dose of about 5334 C. daubneyi metacercariae for a period of 3 weeks resulting in the build-up of very large numbers of immature worms in the small intestine. It is hypothesized that specific environmental conditions may favour this parasite over its competitor, the liver fluke, Fasciola hepatica, possibly by allowing it to emerge earlier. The possibility that C. daubneyi may be better adapted to the Irish climate than F. hepatica together with the fact that selective treatment against F. hepatica effectively frees the niche for C. daubneyi, may result in the gradual replacement of F. hepatica by C. daubneyi.