I’ve seen a couple horses colic as they tried to shed a massive parasite load after deworming. That’s why I was so willing to dose them 2X per year.
That is for sure. I brought one mule home from the sale in MO and as I always did, wormed her before I put in with others. She almost died from the load of worms. It was a pile about as big as a cow pie.
Some of these horses and mules a person get that are calm and docile become whole lot more of a horse or mule after getting all the worms cleared up.A few more than you want
