Anthelmintic efficacy testing against gastrointestinal nematodes of cattle at central Ethiopia

Abstract

Background : Anthelmintic resistance is a pressing issue in current animal production. This study was performed to evaluate the efficacy of commonly used anthelmintics; Albendazole (ABZ), Nizal (NIZ), and Tetraclozan (TETC) in naturally infected dairy cattle in Holeta, central Ethiopia. Methods : Fifty-two animals were assigned to four groups: three groups received oral treatments with ABZ, NIZ, and TETC, at the dosages recommended by the manufacturers, while the fourth group served as an untreated control. Fecal samples were collected on day 0 (pre-treatment) and analyzed using the flotation technique and the modified McMaster egg counting method to determine baseline parasite loads. A coproculture procedure was also followed to identify the gastrointestinal nematode genera in the study animals. The same method was used on day 14 (post-treatment). The efficacy of each anthelmintic was subsequently measured via the fecal egg count reduction test (FECRT). Results : The study revealed that NIZ and TETC had efficacy, with FECRT values of 100% and 95%, respectively, against gastrointestinal nematodes of dairy cattle in the study area. However, ABZ was suspected to have anthelmintic resistance against gastrointestinal nematodes of dairy cattle, with an FECRT value of 91.5%. Coproculture recovery of nematode larvae from infected dairy cattle showed five genera of GI nematodes, namely, Haemonchus spp., Oesophagostomum spp., Nematodirus spp., and Bunostomum spp., which were dominated by Haemonchus spp. Conclusion : The results of the study demonstrated the presence of different nematode genera resistant to treatment with ABZ in dairy cattle, which could reduce their productivity. There is a need to complement definitive diagnosis with drug efficacy evaluation techniques.