Multispecies resistance of cattle gastrointestinal nematodes to long-acting avermectin formulations in Mato Grosso do Sul

作者：Borges Fernando de Almeida^*; Lino Borges Dyego Goncalves; Heckler Rafael Pereira; Lordello Neves Juliana Paniago; Lopes Fernando Goncalves; Vilalba Onizuka Marcel Kenzo

来源：Veterinary Parasitology, 2015, 212(3-4): 299-302.

DOI：10.1016/j.vetpar.2015.06.015

• Haemonchus placei
• Cooperia
• Ivermectin
• Doramectin
• Necropsy

The use of long-acting avermectins (AVMs) in cattle to treat infections with gastrointestinal nematodes was common in Brazil until its prohibition by state authorities. The prohibition; however, was rescinded in 2015, but a scientific discussion of the pros and cons of the use of these formulations is necessary. We evaluated the levels of resistance to 1.0 and 3.5% doramectin and to 3.15% ivermectin in cattle. The worms in animals treated with 3.5% doramectin were characterized by the suppression of oviposition and by a higher proportion of adult females carrying no eggs. Haemonchus placei, Cooperia punctata, C. pectinata, C spatulata, and Oesophagostomum radiatum were resistant to the above compositions. The administration of long-acting AVM formulations did not result in a higher efficacy against these helminth populations.

• 出版日期2015-9-15