Longevity of infective larvae of gastrointestinal nematodes of cattle in the Pantanal, Brazil

Abstract

Aiming to determine development and longevity of infective larvae of nematodes of cattle, dung pads were placed on Digitaria decumbens and on native pasture during two years, in the Pantanal region. After placement the dung pad and the pasture were regularly analysed for presence of L₃. It was observed that during the dry season, mainly at the start, the dung pads and the surrounding forage stayed positive for presence of infective larvae for up to six months, while the ones placed during the most raining months remained with L₃ no longer than two months. The results were similar for the forage. It is concluded that in the Pantanal region the free life form finds conditions for development and survival within the dung pad. Larvae migration from the dung pad to the pasture is intermittent, mainly during the dry season. During the raining season, the liberation to the pasture is faster, due to high humidity and direct action of dung beetles and heavy rains.