Efficacy of toltrazuril against different levels of Eimeria tenella Infection in chicken

Efficacy of toltrazuril (BAYCOX, 2.5% w/v a trademark of M/S Bayer) against six different levels (1 x 10³, 5x 10³, 1x 10⁴, 2.5 x 10⁴, 5x 10⁴ and 1 x 10⁵) of Eimeria tenella infection in two-week-old chicks was evaluated. Medication was given @ of 2 ml/liter of drinking water for two consecutive days, 96 hrs. after the induction of infection. The drug was found highly efficacious. The performance indices recorded from the lower levels to the higher levels of infection were: 266, 258, 259, 216, 197 and 135 respectively. The treatment resulted into lowered mortality and reduced occyst production. Moreover, therapy resulted into complete elimination of the clinical signs at lower levels of the infection. The drug interfered in the development of immunity only at the lower levels of infection (1 x 10³ and 5 x 10³ oocysts/bird).