Evaluation of the utility of subjective clinical parameters for estimating fecal egg counts and packed cell volume in Canadian sheep flocks

MEDEROS, AMÉRICA; KELTON, DAVID; PEREGRINE, ANDREW; VANLEEUWEN, JOHN; FERNÁNDEZ, ALICIA SILVINA; LEBOEUF, ANNE; MENZIES, PAULA; MARTIN, RALPH

VETERINARY PARASITOLOGY

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2014 vol. 205 p. 568 - 574

0304-4017

A study was conducted in sheep on Canadian farms to describe the relationship betweenpacked cell volume (PCV) or fecal egg counts (FEC) and subjective clinical parameters thatmay indicate the severity of parasitic gastroenteritis. Twenty-one farms in Ontario (ON) and8 farms in Quebec (QC) were purposively selected and visited during April?May (spring)and August (summer) 2007. At each farm visit, blood and fecal samples were collected from10 ewes and 10 female lambs; body condition score (BCS), dag score (DS), fecal consistencyscore (FCS) and FAMACHA score were recorded for all sampled sheep. Packed cell volumewas determined for all blood samples, and FEC were performed for all fecal samples. Sum-mary statistics and simple correlations were performed for the parameters recorded. Twomixed models with random effects at the farm level were developed; one using PCV asthe response variable and another using the natural log of eggs per gram of feces (lnEPG).Finally, the residuals from both models were correlated to the covariates in the models. Themean PCV values during the spring were 29.7% and 36.7% for lambs, and 28.8% and 31.1%for ewes, in ON and QC, respectively. During the summer, the mean PCV was 32.0% and32.8% for lambs, and 30.1% and 29.9% for ewes, in ON and QC, respectively. The arithmeticmean FEC per gram of feces (EPG) during the spring was 3 and 2 for lambs, and 1266 and789 for ewes, in ON and QC, respectively, whereas during summer the arithmetic meanEPG was 907 and 237 for lambs, and 458 and 246 for ewes, in ON and QC, respectively.Results from simple correlations indicated that PCV was negatively correlated with lnEPG(r = −0.255; r2= 6.5%) and FAMACHA (r = −0.312; r2= 9.7%), and positively correlated withBCS (r = 0.317; r2= 10%). LnEPG was negatively correlated with BCS (r = −0.232; r2= 5.4%)and PCV (r = −0.255; r2= 6.5%), but positively correlated with FAMACHA (r = 0.178; r2= 3.2%) and DS (r = 0.086; r2= 0.7%). Results from the models indicated that PCV and lnEPG residualswere negatively correlated with FAMACHA, FCS and almost all categories of BCS and DS,although the correlations were very low. The main results from this study suggested thatnone of the subjective clinical parameters evaluated were highly correlated with PCV orlnEPG and therefore were not good predictors of lnEPG or PCV on the studied farms inOntario and Quebec