In vivo anthelmintic efficacy and physiological effects of Swertia chirata in Barbari goats naturally infected with Haemonchuscontortus

Haemonchus contortus remains one of the most economically devastating gastrointestinal nematodes in small ruminants, with escalating anthelmintic resistance threatening sustainable parasitic control. The present study evaluated the in vivo efficacy, safety, and physiological effects of an aqueous whole-plant extract of Swertia chirata against naturally occurring H. contortus infections in Barbari goats under field conditions. Thirty goats with faecal egg counts (FEC) ≥ 1000 eggs/g were randomly allocated into five groups (n = 6): untreated control, closantel (10 mg/kg), and S. chirata extract at 50, 250, and 500 mg/kg body weight. Infection was confirmed as mono-specific H. contortus by ITS-2 PCR and phylogenetic analysis. Anthelmintic efficacy was assessed using WAAVP-compliant faecal egg count reduction tests (FECRT), and associated haematological, biochemical and antioxidant alterations were evaluated over 28 days. Closantel achieved a 100% FEC reduction by day 14. The highest extract dose (500 mg/kg) produced a significant, dose-dependent reduction in egg shedding, reaching 60.65% by day 28 (P < 0.05), whereas lower doses showed minimal efficacy. Notably, high-dose treatment resulted in significant improvements in haemoglobin, packed cell volume, total serum protein, and ferric reducing antioxidant power, accompanied by a reduction in eosinophilia, without evidence of hepatic or renal toxicity. Although the efficacy did not meet the ≥ 95% WAAVP threshold for standalone anthelmintic classification, the extract demonstrated measurable in vivo activity and adjunct physiological benefits. These findings provide field-based evidence supporting S. chirata as a safe complementary phyto-therapeutic candidate for integrated parasite management strategies aimed at reducing reliance on synthetic anthelmintics in small ruminant production systems.