Avaliação do Método Famacha© como estratégia auxiliar no controle de helmintoses gastrintestinais de ovinos no Semiárido da Paraíba, Brasil.

Abstract

Production of sheep is an activity widely exploited in the Northeast, especially in semiarid region. However, gastrointestinal parasite are the major limitant factor for production of small ruminant, causing financial prejudice. The most used control method is the chemical one, however, the exacerbated use of this method, contributed for appearance of anthelmintic resistance. Because of this, many others alternatives of control have been studied. The FAMACHA© method is one of these alternatives. This method should be used when the main parasite in the flock is the Haemonchus contortus. The method is based on correlations between the colour of the mucous membranes of the eyes of sheep and a colour chart with five colour categories depicting varying degrees of anemia, indicated by blood exams that measure the percentage of red cells (KAPLAN et al., 2004). The use of this method allows treat just a part of the flock, the anemics. It could observe a decrease in antiparasitic drug usage, reducing costs and the environmental contamination with chemicals and reducing the pressure for anthelmintic resistance. With so many benefits, it is important that the performance of this method should be evaluate under different management and environmental conditions. This research was divided into two chapters, the first one had the objective a study theoretical on the production of sheep and the FAMACHA© method. The second one had the objective to evaluate the FAMACHA© method as na auxiliary strategy for the control of the gastrointestinal helminths parasite of mixed breed sheep, naturally infected in semiarid of Paraiba state. It were used 313 sheep from 10 farms located in Patos, São José de Espinharas, Condado and Pombal. It was made one visit on each farm during the period July through December 2010, when were collected from each animal fecal samples for performance of fecal egg counts (FEC) and larvae culture. Blood samples were collected from each animal for determination of packed cell volume (PCV). Concomitantly, the color of the ocular conjunctiva of all animals were scored using the FAMACHA© card. To compare the relationship between the FAMACHA© score, PVC and FEC was used Spearman correlation coefficients using SAS (2003). Correlations between PVC and FAMACHA© score, PVC and FEC, and between FEC and FAMACHA© score was significant (P < 0.01; P < 0.02; P < 0.10, respectively). Data for both FAMACHA© scores and PVC were evaluated using two separate criteria for anemia: eye score values of 3, 4 and 5 or 4 and 5, and PVC values of ≤ 19 or ≤ 15 were considered anemic. The specificity was good at 90% into FAMACHA© categories 4 and 5, and 70% into categories 3, 4 and 5. The Sensitivity was poor at 31% into categories 4 and 5, and increased to 80% into categories 3, 4 and 5 for a cut-off haematocrit value for anemia of less than 19%. When this value was less than 15% the sensitivity was 66%. The predictive value of a positive were low, however the predictive value of a negative were high. These data indicate that the FAMACHA© method is an useful tool for identifying anemic animals.