In Uruguay, the lack of efficacy of the majority of the anthelmintic drugs available in the market is jeopardicing sheep production systems.

In Uruguay, anthelmintic resistance (AR) is a wide spread phenomenon amongst sheep farms and the main resistant and abundan speciesis Haemonchus contortus (H.contortus). This study aimed to implement the adoption of a targeted selective treatment program using the Famacha© system, to reduce the selection pressure of resistant H.contortus among sheep, under extensive farming.