Evaluation of lyophilized Tanacetum vulgare extract in intraruminal bolus and granule forms for gastrointestinal nematode control in sheep: An in vivo clinical study.

Background and aim: Gastrointestinal nematode infections have a significant impact on the health and productivity of sheep worldwide. Conventional anthelmintics are facing rising resistance, prompting the need for alternative control strategies. Tanacetum vulgare (tansy), a traditionally used antiparasitic herb in Latvia, has shown in vitro efficacy but lacks in vivo delivery validation. This study aimed to evaluate the in vivo antiparasitic efficacy and safety of T. vulgare extract administered through novel intraruminal boluses and granules in naturally infected sheep.

Materials and methods: Thirty female Latvian Darkhead lambs (4-5 months; mean 35 ± 0.8 kg) were randomly assigned to five groups: Two bolus groups (A and B), one granule group, and two controls (negative and positive). Groups A and B received intraruminal boluses with different lyophilized extract formulations, the granule group received powdered T. vulgare mixed with feed, and the positive control received levamisole. Fecal egg counts (FECs), clinical signs, and hematological and biochemical parameters were assessed over 56 days. Disintegration testing simulated rumen conditions.

Results: No adverse clinical or physiological effects were observed. Bolus groups exhibited a more rapid and consistent reduction in strongylid FECs compared to the granule and negative control groups. On day 56, egg counts decreased to 325-358 eggs per gram (EPG) in bolus and granule groups, compared to 533 EPG in the negative control. Hematological and biochemical parameters remained within reference ranges.

Conclusion: T. vulgare extract administered through intraruminal bolus was safe, sustained animal health, and effectively reduced gastrointestinal nematode burden. Granules were less effective, potentially due to reduced palatability. Bolus-based phytotherapy may serve as a sustainable, prophylactic alternative to conventional anthelmintics.