Evaluate the efficacy of anthelmintics and dosing practices in goats

Summary

Producers hada number of registered veterinary chemicals at their disposal with which to manage internal parasites in goats, but they all stemmed from technology more than three decades old and were all blighted by varying degrees of drench resistance in the nematodes they aimed to control. The efficacy of 3 anthelmintics registered for use in goats, oxfendazole (OFZ), morantel citrate (MOR) and abamectin (ABA) were assessed individually and in combination against resistant strains of Haemonchus contortus and Trichostrongylus colubriformis over 3 experiments. 
For each experiment, Boer cross goats were sourced from a local supplier, treated to remove helminth parasites and then infected with 4000 L3 H. contortus Gold Coast 2004 and 8000 L3 T. colubriformis Gold Coast 2004. Faecal worm egg counts (WEC) were carried out at Days 25, 28, 32, 35, 39 and 42 post infection. Anthelmintic treatments were applied after allocation to groups after WEC at Day 28 and slaughter of all goats for worm burden estimation occurred on Days 43-44.   Anthelmintic treatments were: 
Experiment 1 
OFZ, MOR, ABA, OFZ+MOR, OFZ+ABA, MOR+ABA, OFZ+MOR+ABA delivered orally at the manufacturers recommended dose rate. The combinations were delivered sequentially. 
Experiment 2
OFZ+MOR, OFZ+MOR+ABA (delivered sequentially) and Monepantel (MPL) delivered orally at 1.0 or 1.5 times the manufacturers recommended dose rate and some groups were fasted for 16 hours before treatment. 
Experiment 3 
OFZ+MOR+ABA (delivered sequentially), commercial equivalents to the combinations used i.e. Triguard (TRI) and  Scanda (SCA) and MPL delivered orally or by intra-abomasal injection. Prior to infection with parasites, goats in this experiment were given 12 mL of 30% glucose solution by conventional oral dosing, head-up dosing, front-of-mouth dosing, intraruminal injection or intra-abomasal injection to determine the likely effects of dosing technique on oesophageal groove closure and ruminal bypass of the dose.