ABSTRACT
Nine ponies, aged 12 months at the time of infection, were randomly allocated to one of three groups. Each pony was infected with 30,000 infective cyathostome larvae stored 4 weeks under the natural environmental conditions of the Czech Republic. Horses of Group A were infected with larvae conditioned from August 16 to September 12 (the first phase of the experiment). Horses of Group B were inoculated with larvae conditioned from October 10 to November 4 (the second phase of the experiment). In the third phase, horses from Group C received larvae stored under natural conditions (from 8.11 to 18.11.2011). The larvae were then kept under laboratory conditions (5 °C, the light reduction according to the nature condition). In the first and second phase of the experiment, 98.57% and 95.48% of adult nematodes were found, respectively. However, only 29.07% of adults were found in the third phase of experiment, and the proportion of arrested larvae (EL3) was 67.73%. The share of these larvae in the cecum during last phase of the experiment comprised 92.59% of all cyathostomes.