The efficacy of AMMO Allwormer for the treatment of resistant ascarids in foals across three regions of NSW

Parascaris spp. are the most pathogenic parasites of immature horses and can result in poor growth, ill-thrift, colic and death subsequent to intestinal impaction or perforation. Anthelminitic drugs remain the mainstayof control programmes for these parasites in foals; however, there is increasing evidence of anthelminticresistance in Parascaris equorum (PE). Resistance of PE to macrocyclic lactones (MLs) is recognized in many countries and additional treatment options for these parasites are desirable to maintain the efficacy ofcontrol programmes. Synergistic efficacy of anthelmintic combinations against nematode parasites of otherspecies has been reported and such strategies may be useful in the management of PE in horses. The purpose of this study was to determine the efficacy of an abamectin (ABA) and morantel (MOR) combination(AMMO Allwormer) for the treatment of ivermectin (IVM) and ABA resistant PE. Two separate trials wereconducted in this study, the first in the Sydney and Hunter regions (T1) and a second in Southern NSW (T2).