Hello and welcome to another segment of Ask a Farrinarian. My name is Brian Eitelman. And
today I will be talking about parasite management and deworming strategies. This video stems from
some questions I get fairly often about "Do I recommend rotational deworming?" and "Do I
recommend fecal egg counts?" The issue, before I get rambling too far, is more about parasite
management than parasite elimination. There will always be parasites. Parasites have parasites.
This video is about some of the key points and strategies in the management of parasites here
in Colorado. Simply put, twice-yearly deworming should be more than sufficient, three times a year
at most. Great times are right before grazing season starts, kind of in the late spring,
and after it ends in the early fall. The main reason why is that deworming before grazing season
limits the shedding of eggs actually out onto the pasture, and deworming after grazing season allows
you to address the parasites they have inevitably picked up while they were grazing. The two most
reliable products are ivermectin or moxidectin and pyrantel. The generics are totally fine. Switching
between these two is fine, or if you find that your horse tolerates one better than the other,
stick with that one. Ivermectin is about 99% effective and pyrantel is usually in the high
90's as well. Every 18 months to two years, it's not a bad idea to use a product with
praziquantel to address the tapeworms. Horses don't have huge issues with tapeworms, but it's
still a good idea to deal with them periodically. Dewormers with praziquantel will have names like
"max" or "plus" or "gold." Another product on the market is fenbendazole or panacur. Unfortunately,
this has become much less effective. It really is only effective as the "powerpac" and only then to
get one encysted-phase of one parasite that is resistant to most other dewormers. However it
is very expensive and a large amount of product to ask your horse to tolerate for such a narrow
spectrum of effect. The main take-home message for this whole video is that good husbandry,
good manure-management, and good nutrition, are far more critical to long-term effective
parasite control than any deworming product out there. Without those three, it'd be like choosing
to rely on antibiotics for disease management, rather than washing your hands, cooking your food,
or using flush toilets. We'll break this whole thing down by starting with how horses actually
get parasites. The primary spread is fecal-to-oral which simply means "poop in the mouth." Internal
parasites pass out of the host animal in their manure, then while it's outside the host, the eggs
mature to the stage in which they are infective to the other animals, and hang out and wait to
be eaten and start the cycle all over again. I'll address that maturing time here in a second and
how that factors into manure management. But for now, fecal balls make nice, cozy houses for the
eggs. Hot, dry, sunny conditions make the eggs use their reserve capacity faster and therefore
die off faster. We're very fortunate in Colorado that we have all three of those conditions, hot,
dry, and sunny, for most of the grazing season. The wetter the pasture is or the more shaded the
fecal balls are, the longer the eggs can survive. So why manure management is so important is simply
that grazing through manure is the key step for picking up new parasites. Parasite eggs can become
infective in as little as seven to ten days, and stay infective for six months or even longer,
depending on conditions. If an egg that hasn't matured to that infective stage is ingested,
it simply passes on through and continues on with its life cycle. This is a large part of why
regular and thorough manure removal, at least once weekly, is so key in keeping parasite exposure and
worm burden down. If you can get the manure up and out of the way, the eggs never have a chance
to infect the next horse. There are any number of feeders designed to keep or limit animals
from walking through the hay and defecating in it. Another key point is avoiding overstocking. More
animals mean more manure, more manure means more exposure to parasites. A common guideline for how
many animals a pasture will support is "Can the pasture grow faster than they can eat it down?"
Another key question that should be asked is "Is there sufficient feed in sufficient space for all
of the animals?" So often, the lower animals in the pecking order are forced to grace through
contaminated feed or the dirtiest parts of the pasture. A quick thought on manure spreaders,
they do have a roll. They are cheap, effective methods for manure disposal and for fertilizing
pastures. However, they do serve to reseed the pasture with those same parasite eggs. In my
experience, they can do a great job of busting up the fecal balls, but just through sheer numbers,
a lot of fecal balls do make it back out into the pastures untouched. Nutrition - good nutrition
is important because the immune system is one of the first system sacrificed by the body when poor
nutrition is present. Domesticated animals have developed some inherent resistance and tolerance
to parasites, which is again why we talk about parasite management rather than elimination.
However, inevitably, the immune system is compromised, stressful life, travel, exposure to
new diseases, pregnancy, poor nutrition, or just sheer numbers of parasite eggs they are exposed
to, every animal is susceptible. Good nutrition helps keep the immune system robust and better
able to resist the pressure of parasite exposure. From a practical standpoint, a good nutritional
plane indicates a large supply of good forage. While this sounds obvious, there are several
behavioral observations that are worth noting. Plenty of good forage means that animals can be
pickier about what they eat, meaning that they are less likely to graze through manure-contaminated
feed when there is clean hay two feet away. Lack of good or sufficient forage also means that
animals are forced to graze through poor, contaminated feed or pasture. Very often,
the animals lower in the pecking order have much higher parasite loads because of these points:
Poor hay means a poor nutritional plane. Poor nutritional plane means poor immune system,
and then the animal is a "poor-doer." He's just sick. Which means they eat more of the poorer
quality hay, and the cycle continues. And this puts the healthier animals at further risk. As
far as pasture management, pastures do have a tendency to develop what I call "sweet spots."
Different types of grass some animals like more than others. Also, there are certain areas of the
pastures where horses will tend to congregate and therefore tend to graze more heavily. Why
that's important is that grasses respond to being grazed by growing roots deeper and increasing the
sugar and nutrition content in the remaining plant and then regrowing. This makes the grazed
areas taste better and more likely to be grazed on again, again thereby increasing exposure. You
can have a hundred horses, pardon me, you can have ten horses on a hundred acres and they'll
primarily graze two or three of those acres, and the rest they just kind of walk around in. You
may have stocking rates well below capacity, but they'll choose on their own, to overstock
certain areas. I'll talk about fecal egg counts, and this transitions more to my opinion and kind
of my experience. I understand the idea behind this is as tool for deciding which animals need
deworming and measuring for resistance to those dewormers. In theory, they should be great for
these purposes but, and again this is my opinion and in my experience, fecal egg counts tend to be
unreliable and/or poorly done. I have yet to have any owners tell me their previous egg counts have
found any parasites. I have personal experience with labs returning fecal egg counts of zero,
and then when I check the samples on my own, the sample's loaded with eggs. Because of inconsistent
results, I think fecal egg counts, in large part, give a false sense of security. If I'm
going to do a fecal egg count with a proven and reliable lab, the main thing I'm looking for is
the count before administration of dewormer, and the count afterwards, and I want a significant
drop in that count. Lack of drop in the egg count after deworming is a good indicator of resistance.
A zero egg count to me is more an indication of need to retest and to check test protocol,
rather than a parasite-free animal. A couple of thoughts to ponder: If you think your animals
are at high-risk, what can you do to improve that and lower their risk today, tomorrow,
next week, next month, next year? If you don't think your animals are at high-risk,
double-check that. Spend a day or two and watch their habits. Make sure they're being fed what and
how you expect. Make sure everyone has plenty to eat and isn't forced to graze through poor
pasture or sub-optimal conditions. These simple management steps and strategies really can improve
overall health and wellbeing for your animals. The key point - use dewormers when needed and,
as a tool, not as the keystone. Dewormers without good management will only result in you and your
horse being messy, covered in dewormer, mad for no actual benefit, and will serve only to speed
resistance to dewormers. Thanks for taking a few minutes to watch. If you've gotten some
helpful information out of this, please feel free to share this video. Keep an eye on the
Aggie Vet and Farrier Services Facebook page and website for future videos. Thanks so much!