Quote:
To reply to Welsummerchicks ivermection question, ivermectin (especially the Zimectrin Gold) is the broadest spectrum wormer on the market, because of this it is also the most toxic. It kills the most rapidly for both the adult and larvel stages of parasites. When the adult and larvel stages of most parasites are killed (via deowrming), you create bleeding and inflamation in the walls of the bowel. So, while ivermectin is a good dewormer, in a heavily impacted horse it is not a good choice to use to off the first wave of worms.
In heavily impacted horses, the initial doses of medication like Strongid are small and given daily. At that point a full dose of the same dewormer is given if the horse has tollerated the treatment. At that point, you deworm the horse again with ivermectin in small doses daily for a week then give the horse a full dose of ivermectin. Once the horse is worm free then it can go on a rotation.
Ideally a vet would do a fecal float to idenify the types of parasites and access the horse's health to determine a cource of treatment. I agree with you that in this case, if the conditions remain as they are, the posiblity of re-infestation is high, A way for the owner to combat that would be to give a daily dewormer- pellets or granuels (Strongid 2CX works great) in the horses rations.