2022-06-062022-06-062022-06-062019-12-10http://repositorio.ifam.edu.br/jspui/handle/4321/844Sheep farming is an activity of great importance in the country, it is based on the exploitation of meat, and wool. But facing a big problem in its expansion: the occurrence of verminosis in sheep herds. This disease causes serious economic damage. Because it decreases investment and increases mortality rates. Thus, for treatment, several classes of anti-helminthic are used. However, due to indiscriminate use, parasites develop resistance, making protocols ineffective. The aim of the study is to know the resistance anti-helminthine in sheep after the use of monepantel in lambs. In addition, to diagnose the situation of anti-helminthian resistance in these animals and quantify the parasitic load in different breeds and crosses. The study was conducted with 90 animals and administered monepantel (2,5 mg/kg, orally). The evaluation was performed in different breeds and crosses: G1 - Ile de France (n=12), G2 - Ile de France cross (n=12), G3 - Poll Dorset (n=4), G4 - Texel (n=4), G5 - Sulffolk (n=6), G6 – Suffolk cross (n=7), G7 - Santa Inês (n=11), G8 - Dorper x Santa Inês cross (n=4), G9 - Dorper cross (n=15) e G10 - White Dorper cross (n=15). Feces collection and egg count per gram of feces (EPG) were performed in two moments for evaluation: M1 – before administration of the drug and M2 – 14 days later. The maximum reduction in OPG count was 100% in the Texel breed and Dorper with Santa Inês cross. The Dorper cross was the lowest reduction in EPG count with 32.45%. Purebred sheep had lower number of EPG for Strongyloidea (M1 280,55 ± 536,526; M2 35,13 ± 105,97) compared to animals from crosses (M1 887,27 ± 1382,12; M2 407,27 ± 772,16). Parasitic resistance to monepantel was observed in eight of the ten breeds and crosses used in the study for Strongyloidea.Acesso Aberto1. Ovino. 2. Manejo sanitário. 3. Endoparasita. I. Sousa, Isadora Karolina Freitas de. II. Título.CNPQ::CIENCIAS AGRARIAS::MEDICINA VETERINARIATrabalho de Conclusão de Curso