Join Date: Feb 2012
Location: The land of Enchantment
Like freemare said, it depends on your climate and the time of year. It also depends on the environment. Tape worms, for example, require a 2nd "host" that is found in grass...so there is a larger threat in lush grasses. However, this doesn't mean you shouldn't ever deworm for them in an arid environment. Some parasites do not thrive well after they are pooped out in heat, some in cold. These are a few of the reasons why a schedule needs to be tailored to the specific horse(s) to be effective.
There is just as much horse sense as ever, but the horses have most of it.