INVESTIGADORES
FERNANDEZ Alicia Silvina
congresos y reuniones científicas
Título:
Population dynamics of gastrointestinal nematodes in organic and conventional sheep farms in Canada - Descriptive statistics
Autor/es:
MEDEROS, AMÉRICA; FERNÁNDEZ, ALICIA SILVINA; PEREGRINE, ANDREW; KELTON, DAVID; MENZIES, PAULA; VANLEEUWEN, JOHN; LEBOEUF, ANNE; CORRIVEAU, FRANCOISE; GUTHRIE, ALESSIA; MARTIN, RALPH
Lugar:
Stavanger
Reunión:
Conferencia; 7th International Sheep Veterinary Conference; 2009
Resumen:
The sheep industry of Ontario and Quebec are managed much differently and experience a more extreme climate than those of traditional sheep-raising countries. In these provinces, summers tend to be hot and humid with short dry spells, but winters, while having mostly sub-zero temperatures, may have variable snow cover and free-thaw events. These factors may affect the epidemiology of GIN parasites in organic and conventional sheep flocks in those two provinces. Thirty-two farms were enrolled in the spring of 2006 and were requested not to perform any routine use of anthelmintics. The following sampling was done monthly from spring of 2006 to fall of 2008: fecal egg counts (FEC) from 10 ewes and 10 lambs per flock; pasture larval sampling; individual sheep data, e.g. fecal consistency, PCV, FAMACHA scores, DAG and body condition scores (BSC); and flock level data, e.g. pasture management and grazing practices. Regional weather data was also collected on temperature, humidity, and type and level of precipitation. Larval identification was performed on fecal and pasture samples. Results: Eight certified organic farms, 16 non-certified organic farms, and 7 conventional farms participated in the project. Overall there was significant variability between flocks but some patterns are evident. FEC appear to be similar between organic and conventional flocks. Quebec ewes tended to have higher FEC than Ontario ewes, but Quebec lambs had lower FEC than Ontario lambs. In both provinces ewes had elevated FEC in the spring and the labs experiences a peak in late summer and early fall. Pasture infectivity is highest in June and July, and then again in September. BCS did not vary but DAG score was highest in the spring and decreased through the summer. Proportion of larval species varied by farm but Trichostrongylus sp appear to be the most prevalent GIN in sentinel lambs slaughtered in the fall. In a proportion of the flocks there is evidence of overwintering of L3 Haemonchus contortus on pasture. These data are being analyzed to develop a statistical model to investigate factors affecting outcome variables. These models will be used to develop a strategic and sustainable parasite program for Canadian sheep flocks.