Diarrhoea in intensively-reared lambs

Treatment against coccidiosis in Norwegian lambs and potential risk factors for development of anticoccidial resistance-a questionnaire-based study

The objectives of this study were to investigate the use of anticoccidials in Norwegian sheep flocks and identify farms with management procedures likely to select for drug resistance. Data were obtained by a questionnaire sent to all members of the Norwegian Sheep Recording System in October 2015. The data set consisted of 1215 answers, corresponding to 8.5% of Norwegian sheep flocks. Anticoccidials were used in 82.7% of flocks. Main treatment was at turnout (38.6% of treated flocks) or 1 week after turnout (32.4%). Interestingly, clinical signs possibly related to coccidiosis were observed by almost 40% of the farmers after treatment, which might be an indication of drug resistance. Correlations between the apparently reduced anticoccidial efficacy and management conditions, such as the size of the farms, were found. From the farmers' perspective, metaphylactic treatment was used in 88.5% of treated flocks, of which approximately one third had no history of clinical coccidiosis. Even though farmers seem aware of the importance of good drenching routines based on reliable estimates of weights and calibration of drench guns, drench gun used for anticoccidial administration was never calibrated in 12.1% of the flocks. Finally, dose estimation was made by visual appraisal in 27.5% of the flocks, which can lead to incorrect dosing. Based on the present study, it cannot be determined whether the apparent treatment failure was related to management practises, incorrect administration of the drug, other infections or actual anticoccidial drug resistance.

Dinâmica da infecção natural por Eimeria spp. em cordeiros da raça Santa Inês criados em sistema semi-intensivo no Norte de Minas Gerais

Primo-infecção por Eimeria spp., evolução da infecção e principais espécies presentes foram avaliadas em 30 cordeiros da raça Santa Inês, machos, lactentes, criados em sistema semi-intensivo no Norte de Minas Gerais. A detecção inicial de oocistos nas fezes ocorreu entre o 16º e o 32º dias de idade e a espécie mais freqüente foi E. ovinoidalis (52,8%). A excreção de oocistos até a 16ª semana de idade caracterizou-se por aumento gradual a partir da segunda semana, com picos na sétima e na 10ª semanas. O segundo pico foi mais baixo que o primeiro, com queda mais persistente, indicando o desenvolvimento de imunidade. Foram identificadas 11 espécies de Eimeria: E. parva, E. ovinoidalis, E. crandallis, E. caprovina, E. ovina, E. ahsata, E. pallida, E. faurei, E. intrincata, E. granulosa e E. punctata. E. crandallis foi a mais freqüente (47,2%). As condições locais e de manejo, apesar de consideradas adversas, foram propícias à esporulação de oocistos de Eimeria spp. e à constante reinfecção dos cordeiros.

A descriptive epidemiological study of coccidiosis in early lambing housed flocks

Infection with Eimeria sp. was studied in 135 lambs born to 79 ewes in four early lambing housed flocks. In three of these flocks two different coccidiostats (monensin and decoquinate) were administered in the feed. Cohort lambs were examined clinically and a rectal faeces sample taken once a week. Samples with more than 300 oocyts per gram were speciated by morphology. Nine species were identified and Eimeria crandallis was the most prevalent. One of the flocks developed clinical coccidiosis before the introduction of coccidiostats. On the remaining farms no differences in the oocyst excretion rate of infected lambs were found between medicated and non-medicated lambs until Visit 6 nor in the proportion of lambs infected until Visit 8. It is suggested that cocciodiosis may be controlled without coccidiostats, by identification of the risk factors associated with disease. Morphological variation of species and collection of large enough faeces samples from young lambs constitute limiting components for further epidemiological studies of coccidiosis.