How will this affect my dogs, horses, etc?

The herbicide SCI REMC uses affects plants only. An active ingredient within the herbicide disrupts the growth process within the plant by affecting enzymes unique to plants. These herbicides do not have a similar effect on animals or insects. However, any compound in a high enough concentration can be toxic. The EPA requires extensive testing before being introduced to the market to assure that there are no unintended effects on pets, livestock or wildlife.