Situation of and phenotypic markers of susceptibility to helminth infection among sheep on farms in the Brazilian cerrado biome

Abstract

This study aimed to determine the intensity, seasonality, and distribution by genera of, as well as to identify phenotypic markers of susceptibility to, gastrointestinal parasites among sheep on farms within the Brazilian savanna (cerrado) biome. We evaluated 1271 sheep, on seven farms, during the rainy season (in December 2017 and December 2018) and dry season (in July 2018 and July 2019). Parasitological evaluation was based on culture and EPG. We calculated hematocrit, as well as the body condition score and feces score. Of the sheep evaluated, 34.15% had moderate-to-severe parasitic infection. The factors of herds’ phenotypic characterization about helminth infections were (p ≤ 0.05 for all): anemia (OR = 5.72); leanness (OR = 1.80); loose stools or diarrhea (OR = 1.54); breed other than Santa Inês (OR = 2.31); “weaned lamb” category (OR = 4.76); “lambing ewe” category (OR = 4.66); and dry season (OR = 2.37). Haemonchus, Trichostrongylus, Oesophagostomum, and Cooperia accounted for 76.40%, 20.23%, 2.89%, and 0.47%, respectively, of the helminth genera identified, with their proportional distributions being comparable between the rainy and dry seasons. Changes in health management, with regard to helminth infection control, are urgently needed in order to combat the disease more effectively and sustainably.

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

“…The high sensitivity and specificity of the method directly influences the animal's health by reducing the use of anthelmintics, and consequently, the pressure of selection of resistant parasites, allowing the maintenance of susceptible helminths (Torres-Acosta, Mendoza-de-Gives, Aquilar-Caballero, & Cuellar-Ordaz, 2012). Considering that deworming en masse is a common practice to control gastrointestinal parasites in sheep production systems in the Brazilian Cerrado (Moreira, Mota, Gonçalves, Rocha, & Borges, 2021), correcting this practice through the implementation and routine use of the FAMACHA © technique will significantly reduce the unnecessary use of anthelmintic drugs in healthy animals. It also lowers costs by reducing the number of treated individuals.…”