Helminthiasis characterization and anthelmintic efficacy for ewes and lambs raised in tropical semiarid region

Abstract

In this study the helminthiasis and anthelmintic effectiveness in ewes and lambs were evaluated in a semiarid region of Brazil. Twelve sheep farms were investigated using semi-structured questionnaires and fecal egg count (FEC) reduction test was employed to analyze the profile of anthelmintic resistance. Groups of at least 10 animals with FEC ≥ 300 were selected. After 12 h of fasting, homogeneous groups of lambs or ewes were treated with albendazole, levamisole moxidectin, or oxfendazole and control groups were not treated. Feces were collected before treatments and 14 days after, and larvae genera were identified after cuprocultures in both periods. Extensive grazing was the predominant creation system, using hybrid Santa Ines animals. The separation by age was promoted in 75% of herds; however, maternity pickets there were only in three farms. The strategic treatments were performed only in 8.4% of sheep farms and 16.6% used the anthelmintic efficacy test and alternated anthelmintic classes after 1 year. The initial FEC means for lambs were significantly higher than ewe FEC averages. For lamb tests, moxidectin and levamisole showed higher efficacy (p ≤ 0.05) than benzimidazoles. For ewe tests, moxidectin and levamisole showed efficiencies >75%. Haemonchus spp. and Trichostrongylus spp. were the most frequent nematodes before treatments and the genus Haemonchus was the most prevalent after anthelmintic treatments (p < 0.05). Variations of anthelmintic susceptibility were observed for categories and herds evaluated, which emphasizes the importance of the effectiveness tests for the choice of anthelmintics for ewes and lambs.

Efficacy of Tithonia diversifolia (Hemsl) A. Gray on the inhibition of larval development of Haemonchus contortus

“…Treatment with T. diversifolia stem powder showed better results when used at a concentration of 326.66 mg of stem powder per gram of coproculture, which resulted in an LDI efficacy of 31.0%, presenting a significant reduction in the LPGF mean number produced, as compared to the control with distilled water (Table 1). Because of the high tolerance to anthelmintics reported in different regions, mainly for albendazole (BASTOS 2017, DUARTE et al 2012, the search for alternatives for the integrated control of this nematode has been persistent. The results of this study present the use of T. diversifolia leaves as an important measure for the control of resistant nematode strains.…”

Influence of fasting on the efficacy of anthelminthics in naturally infected sheep

“…The safety margin for levamisole is four to eight times the recommended therapeutic dose of 7.5mg/kg. For instance, studies conducted by Duarte et al (2012) and Bastos et al (2017) evaluated the efficacy of oral levamisole in sheep and kept the animals fasting prior to drug administration and they did not report signs of intoxication in the animals.…”