FAMACHA(©) scores history of sheep characterized as resistant/resilient or susceptible to H. contortus in artificial infection challenge.

With the aim of validating the FAMACHA(©) as a method for phenotypic selection of sheep resistant/resilient to gastrointestinal nematodes, 27 Suffolk ewes with known FAMACHA(©) score histories were experimentally infected with 25,000 larvae of Haemonchus contortus. From the day of infection (day 0) to 60 days post-infection, at intervals of 7-15 days, ewes were evaluated for packed cell volume (PCV) and fecal egg counts (FEC). A statistically significant increase (p<0.05) in FEC occurred between day 0 and day 60. PCV values showed a decrease (p<0.05) starting from day 21, compared to day 0. Based on the changes in FEC and PCV values from day 0 to day 60, 15 ewes (55.56%) were classified as susceptible (S) and 12 ewes (44.44%) as resistant/resilient (RR). A comparison of the average FEC after infection between susceptible (4487.6 eggs per gram-epg) and resistant/resilient (1317.9epg) ewes showed a significant difference (p<0.05) between the two groups. The difference in average PCV values after infection (24.8% and 30.3% for S and RR, respectively) was also significant (p<0.05). Data from 980 previous evaluations of FAMACHA(©) scores from the 27 ewes showed that 58.33% of the ewes classified as RR and 46.67% of the S group had a history of only F1 and F2 scores. In the RR group, only one animal (8.33%) had an F4 score, occurring one time out of the 61 evaluations of this ewe. In contrast, 40.0% of S group ewes had F4 and/or F5 scores. During the period of FAMACHA(©) score history that was evaluated, 69.56% of the total number of anthelmintic treatments in the flock were administered to ewes from group S. Since ewes with F4 and/or F5 scores during the FAMACHA(©) score time period were classified as susceptible during the experimental infection (with the exception of one ewe), we conclude that the FAMACHA(©) score history is a useful tool for the selection of ewes that are resistant/resilient, as well as for the identification of susceptible animals that should be culled.

Pereira JF ，Mendes JB ，De Jong G ，Maia D ，Teixeira VN ，Passerino AS ，Garza JJ ，Sotomaior CS ... -  《-》

Validation of the FAMACHA eye color chart for detecting clinical anemia in sheep and goats on farms in the southern United States.

Kaplan RM ，Burke JM ，Terrill TH ，Miller JE ，Getz WR ，Mobini S ，Valencia E ，Williams MJ ，Williamson LH ，Larsen M ，Vatta AF ... -  《VETERINARY PARASITOLOGY》

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

A study was conducted in sheep on Canadian farms to describe the relationship between packed cell volume (PCV) or fecal egg counts (FEC) and subjective clinical parameters that may indicate the severity of parasitic gastroenteritis. Twenty-one farms in Ontario (ON) and 8 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 from 10 ewes and 10 female lambs; body condition score (BCS), dag score (DS), fecal consistency score (FCS) and FAMACHA score were recorded for all sampled sheep. Packed cell volume was determined for all blood samples, and FEC were performed for all fecal samples. Summary statistics and simple correlations were performed for the parameters recorded. Two mixed models with random effects at the farm level were developed; one using PCV as the 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. The mean 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% and 32.8% for lambs, and 30.1% and 29.9% for ewes, in ON and QC, respectively. The arithmetic mean FEC per gram of feces (EPG) during the spring was 3 and 2 for lambs, and 1266 and 789 for ewes, in ON and QC, respectively, whereas during summer the arithmetic mean EPG 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; r(2) = 6.5%) and FAMACHA (r = -0.312; r(2) = 9.7%), and positively correlated with BCS (r = 0.317; r(2) = 10%). LnEPG was negatively correlated with BCS (r = -0.232; r(2) = 5.4%) and PCV (r = -0.255; r(2) = 6.5%), but positively correlated with FAMACHA (r = 0.178; r(2) = 3.2%) and DS (r = 0.086; r(2) = 0.7%). Results from the models indicated that PCV and lnEPG residuals were 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 that none of the subjective clinical parameters evaluated were highly correlated with PCV or lnEPG and therefore were not good predictors of lnEPG or PCV on the studied farms in Ontario and Quebec.

Mederos A ，Kelton D ，Peregrine AS ，VanLeeuwen J ，Fernández S ，LeBoeuf A ，Menzies P ，Martin R ... -  《-》

Inheritance of fecal egg count and packed cell volume and their relationship with production traits in sheep infected with Haemonchus contortus.

Vanimisetti HB ，Andrew SL ，Zajac AM ，Notter DR ... -  《JOURNAL OF ANIMAL SCIENCE》

Segregation of natural and experimental gastrointestinal nematode infection in F2 progeny of susceptible Suffolk and resistant Gulf Coast Native sheep and its usefulness in assessment of genetic variation.

Miller JE ，Bishop SC ，Cockett NE ，McGraw RA ... -  《VETERINARY PARASITOLOGY》