Effect of levamisole on gastrointestinal nematodes and weight gain of grazing livestock in the municipality of San Jose Chiltepec, Oaxaca, Mexico

Abstract The aim of the present work was to study the effect of administration of levamisole on parasitic load of gastrointestinal nematodes (GIN) and the percentage of weight gain of grazing cattle. The animals were randomly distributed to form three experimental groups, levamisole, ivermectin and control. The collection of feces samples was carried out one day before and 15 days’ post-treatment and subsequently it was quantifying the eggs number per gram of feces. The body weight of the animals was recorded at days 0, 15, 30 and 45 after treatments to evaluate its gain. The results observed up to the final day (45 days’ post-treatment) showed the group treated with Ivermectin had a 10.1% increase in body weight, while the group under Levamisole treatment had an increase of 14.3%. The groups under ivermectin and levamisole showed a decrease in the number of eggs per grams of feces (EPG), which were measured 15 days after their treatment (22.5 EPG in ivermectin) and (55.0 EPG in levamisole) compared to the vehicle group (377.5 EPG) and pre-treatment (486.5 EPG). In the present work, it was possible to show that with two subcutaneous administrations of levamisole in grazing calves in the municipality of Chiltepec, Oaxaca, it’s possible to increase the weight in cattle while decreasing its parasite load of GIN. However, it is necessary to determine the anthelmintic resistance in farms that report the use of levamisole with different treatment and repeated doses of levamisole.