While regular deworming is generally possible, it is questionable due to critical consumer expectations and increasing resistance. Because of the growing resistance in recent years, alternatives for parasite control are being sought. Secondary plant compounds, in particular, appear to have some effect, although their efficacy against blood-sucking endoparasites is not clearly demonstrable.
When herbs and spices are used as feed supplements, it is not possible to identify a specific group of active ingredients, such as the condensed tannins found in certain forage plants. All plant material used exhibits one or more properties (anthelmintic, digestive, appetite-stimulating, antispasmodic, etc.).
The aim of this study is to determine whether, firstly, feeding three different commercially available herb and spice-based feed supplements to grazing sheep is practical (using different administration regimes), and secondly, whether an effect on parasite development in the grazing animals can be demonstrated.