Effect of a new long life formulation of ivermectin + abamectin against gastrointestinal nematodes and the difference in weight gain in bovines

Abstract

With the aim to evaluate the effect of ivermectin 2.25% + abamectin 1.25% in the reduction of gastrointestinal nematodes eggs per gram (epg) and the weight gain in bovines in 90 days, twenty four Santa Gertrudis breed, weaned calves localized in a ranch in Malpaso, Tecpatan municipality, Chiapas, Mexico, with a warm humid climate, were used. The calves were in extensive grazing on African Star and native grasslands. They were naturally infected with gastrointestinal nematodes (GIN), and were weighed on day -3. According to the individual weight and the egg count, two groups of 12 animals each, were integrated, without statistical difference in the weight and the average of epg, above of 700 eggs (P < 0.05). Group 1 was treated with one formulation of ivermectin at 2.25% + abamectina at 1.25%, in doses of 700 mcg/kg corresponding to 1 ml per 50 kg, by subcutaneous via. Group 2 was the control without anthelminthic treatment. Coprological examination was done at – 3, 10, 45 and 90 days, moreover, coprocultures from each group were prepared with homogenized feces, in order to obtain larvae (L3). Weights were recorded on  -3, and 45, 90 days after treatment. It was found that weight gain between Group 1, treated with 2.25% ivermectin + 1.25% abamectin, was 30.7 kg, equivalent to 350 g per day in average, with significant statistical difference (P < 0.05), in relation to the control group. The reduction percentage of epg showed difference at 10 and 45 days (P < 0.05), between the control and treated group; however, at 90 days they were not different. The genuses of GIN identified by frecuency order were: Haemonchus, Coope-ria, Trichostrongylus, Oesophagostomum and Ostertagia.