FAMACHA©: Predictive value for control of Haemonchus sp. in sheep from Brazilian Cerrado

Abstract

This study aimed to evaluate the sensitivity and specificity of FAMACHA© method, correlating with packed cell volume (PCV) and egg count (FEC), as well as to evaluate the clinical signs of Haemonchus sp. infection in sheep from Brazilian Cerrado. Over two years (2017 to 2019), 1,435 sheep were subjected to clinical and parasitological evaluations. Sheep from six breeds (Santa Inês, Dorper, White Dorper, Ile de France, Suffolk, and crossbreed) were subdivided into five production categories (pregnant, lactating, non-pregnant/lactating ewes, breeding males, and weaned lambs). Parasitological evaluations included FEC and coproculture. In the clinical evaluation, all sheep underwent determination of the FAMACHA© score and PCV. Haemonchus sp. larvae were predominant in coprocultures of the flocks (76.4%) and in each animal production category evaluated (69.4 to 84.3%). FAMACHA© method showed high sensitivity (70.6%) for evaluating sheep with scores ≥ 3, and PCV < 23%, and high specificity (97.5%) in animals with higher scores (4 and 5), and PCV < 18%. A negative correlation was observed between FAMACHA© scores and PCV (-0.46) and between PCV and FEC (-0.47), while a positive correlation was observed between FAMACHA© scores and FEC (0.22) (p < 0.01). The vast majority of the animals evaluated (54.5%) were clinically resistant to gastrointestinal parasites. Due to the high sensitivity and specificity, we concluded that the method could be a valuable diagnostic alternative and an ancillary tool in the implementation of selective treatment for helminthic infection in sheep from Brazilian Cerrado.