Benzimidazole resistance in Sheep in detected by faecal egg count reduction test, egg hatch assay and allele-specific polymerase chain reaction (PCR) in gastrointestinal nematodes across agro-climatic zones of Haryana

This study investigated benzimidazole resistance across different agro-climatic zones of State of Haryana using a combination of phenotypic and molecular diagnostic approaches. faecal egg count reduction test (FECRT), egg hatch assay (EHA), and Allele-specific PCR (AS-PCR) to evaluate drug efficacy and detect mutations associated with resistance. Results showed variable resistance levels among zones, with FECRT and EHA confirming reduced anthelmintic efficacy. The AS-PCR provided clear molecular evidence of resistant alleles. Notably, no homozygous susceptible genotypes were detected and approximately 90% of isolates carried homozygous resistant alleles. Or results showed that the integrated FECRT, EHA, and AS-PCR framework validated in this study provides a transferable diagnostic model for resistance surveillance in any resource limited sheep producing region.