Evaluating the Efficacy of Rosemary Extract (Rosmarinus officinalis) as a Natural Antiparasitic Agent in Livestock: A Sustainable Approach to Enhance Animal Health

Livestock ectoparasites (ticks, mites, lice, fleas, and bed bugs) reduce productivity and increase control costs; resistance to synthetic agents is rising. To evaluate the in vitro antiparasitic efficacy of ethanolic Rosmarinus officinalis (rosemary) extract against major cattle ectoparasites and to compare killing speed across concentrations. Rosemary leaves were shade-dried, powdered, extracted in ethanol, concentrated by rotary evaporation, and tested in Petri-dish bioassays. Five ectoparasite groups collected from naturally infested cattle were exposed to three extract preparations (low, high, and concentrate/undiluted, ensuring consistency with your protocol). Time-to-death (min) and mortality (%) were recorded. One-way ANOVA with Tukey’s HSD was used (α = 0.05). The extract showed a clear dose-response. The high-concentration formulation (reported as 2 g extract in 6 mL ethanol) produced complete mortality within ~ 5–10 minutes across taxa; mites were most sensitive (~ 5 min) and lice were least sensitive (~ 10 min). Treatment effects were significant (ANOVA, p < 0.001). Ethanolic rosemary extract demonstrates rapid, broad-spectrum in-vitro antiparasitic activity and could support integrated pest management strategies. This study provides a standardized, side-by-side comparison of killing speed across multiple cattle ectoparasite taxa using the same extraction approach and endpoint (time-to-death).