Incidence of helminth infections in water buffaloes in Eastern Amazon, Brazil

Abstract

Gastrointestinal nematode infections were studied in three groups of water buffalo calves (A, B, C) by mean faecal egg counts (EPG), post-mortem examinations and determination of infective larvae (L3) in pasture. Each group was made of twelve suckling calves (1 to 6 months old) and their mothers and twelve weaned animals (7 to 12 months old). Groups A, B, C grazed on cultivated pasture (Belém), native pasture (Marajó Island) and floodable native pasture (Low Amazon region), respectively. Strongyloides papillosus and Toxocara vitulorum were the most prevalent nematodes in suckling buffaloes in all groups. The incidence of these helminths does not depend on environmental conditions. The mean monthly EPG of animals in group A were relatively lower in the period of intensive rainfall and higher in the period of lesser rainfall. The EPG of animals in group B increased sharply during the wet period and decreased during the dry period. Low EPG were found in the animals of group C. The number of L3 from cultivated pasture was lower in the intensive rainfall period and higher in the lesser rainfall period. Larval counts of native pasture increased sharply in the wet period and decreased during the dry period. A small number of L3 was observed on floodable native pasture. Cooperia punctata and Haemonchus contortus were the most prevalent nematodes found upon necropsy of weaned animals in all groups.