INVESTIGADORES
FERNANDEZ Alicia Silvina
congresos y reuniones científicas
Título:
Epidemiological study if gastrointestinal nematodes in sheep under organic and conventional production systems in Canada
Autor/es:
MEDEROS, AMÉRICA; FERNÁNDEZ, ALICIA SILVINA; PEREGRINE, ANDREW; KELTON, DAVID; VANLEEUWEN, JOHN; MENZIES, PAULA; LEBOEUF, ANNE; MARTIN, RALPH
Reunión:
Conferencia; 22nd Conference of the World Association for the Advancement of Veterinary Parasitology; 2009
Resumen:
In order to determine the epidemiology of gastrointestinal nematodes on sheep flocks in Canada, a longitudinal study was carried out May 2006–March 2007 on 23 farms in Ontario and 8 farms in Quebec that were purposively selected. Eight were certified organic (CO), 16 were non-certified organic (NCO) and 7 were conventional (C) farms. On each farm, 10 ewes and 10 female lambs were randomly selected. Monthly visits were undertaken during the grazing season, with two visits in winter. At each visit fecal egg counts (FEC) in eggs per gram (epg) were performed on individual animals, and infective larvae were identified from feces and pasture samples. Multiple clinical parameters were also recorded. Summary statistics and a multilevel mixed linear regression analysis using log epg was fit using SAS 9.1. Overall, the mean FECs were 181 and 509 epg for ewes and lambs, respectively, in Ontario, and 351 and 147 epg for ewes and lambs, respectively, in Quebec. The mean egg counts for the different types of farms were 94, 287 and 235 epg for ewes under CO, NCO and C, while for lambs they were 295, 521 and 417 epg, respectively. From coprocultures, the nematode species that predominated was Teladorsagia sp (50%), followed by Haemonchus sp (19%). In the final model, provincemonth of sampling, temperature, deworming, age, and body condition score (P