Hi, I'm Dr. Taylor, a veterinarian with the Food
& Drug Administration.
Do you have cattle, sheep, goats or horses?
If so, you probably deworm your animals on a regular
basis and it seems to work.
But did you know, even with routine deworming,
you could still have a parasite problem on your
farm?
Resistant parasites can threaten your animals'
health and welfare.
Learning about parasite resistance is the first
step in combatting it.
Let's take a closer look....
Good morning, Rick.
How's the herd?
Oh hi, Doc.
Thanks very much for coming by.
Everything's OK, but I do have some questions.
I recently heard about parasite resistance.
What's your take on that?
Parasite resistance to dewormers is an increasing
problem in all grazing animals - like cattle,
sheep, goats, and horses.
And it's not just a problem here in the U.S.
It's become a problem in other parts of the world,
too.
But today, let's focus on your specific parasite
control program and see if we should adjust anything
based on new recommendations.
Well my herd's about to undergo a regular
deworming but now I'm beginning to wonder if I
should be doing something different?
Can you say more about resistance?
Sure.
Parasite resistance occurs when some parasites
survive treatment with a drug that previously
worked to kill them.
This can happen when parasites are exposed to
a drug repeatedly.
Eventually, they adapt to that drug so it doesn't
kill them anymore.
In other words, if overused, a dewormer may
stop working on your farm.
Ok, well I don't think I have any particular
problems.
I just want to make sure I'm doing what's best for
my animals.
We might not know there's resistance unless we look
more closely.
There's a test called the fecal egg count reduction
test and it's the most common way to detect
parasite resistance on your farm.
We'll collect manure samples from some animals
in your herd just before we treat them with a
dewormer.
Then about two weeks later, we'll collect a
second batch of manure samples.
For both sets, I'll count the parasite eggs under a
microscope.
If the egg numbers in the samples we collect after
treatment aren't reduced by at least 90 percent
from what they were in the samples we collected
before we dewormed your animals, then the
parasites in your animals might be developing
resistance to the very dewormer we used.
The test isn't perfect, but it can still give you
a good idea about how well a dewormer is working
in your animals.
OK, that sounds helpful.... Keep in mind
that resistance to dewormers varies from farm
to farm.
So, resistance on your farm doesn't mean your
neighbor will have resistance, and vice
versa.
Test results should be compared over time on the
same farm.
Keeping good farm records can really help with this.
I do keep really good records, but how do I keep
parasite resistance from occurring in the first
place?
Parasites can naturally develop resistance over
time so we can't completely stop it.
But, we can work together to slow it down and
prevent it from becoming a health problem for your
animals.
For starters, remember that using dewormers
should just be one part of your overall parasite
control program.
So let's start by working together to come up with
a parasite control program that works best for your
farm and that keeps your long term goals in mind.
First, we'll do a fecal egg count reduction test.
How good are you at estimating the weights of
your animals?
Fortunately, my chute has a scale, so I don't really
have to estimate.
Great.
Not giving the correct dose, specifically too low
of a dose, can lead to parasite resistance, so
it's important to give an animal the correct dose
based on an accurate body weight.
Also, remember to always follow the directions on
the dewormer's label.
And since we were talking about the future of your
farm, don't use dewormers for short term production
gains.
Instead, think about your long term objectives.
We want to keep these products effective for as
long as possible, right?
Right.
But it's not only the parasites in the animals
that are the problem.
How Do I keep parasite eggs from occurring in the
pasture?
If you had small pastures and dry lots, periodically
removing manure can help.
But with bigger farms, like yours, you can rotate
pastures with other livestock species, reduce
the number of animals grazing on a particular
pasture, and keep pasture grass sufficiently tall.
Let's go take a look at your pasture set-up to see
what'll be most practical for you.
Great....
It seems like there's not one easy
method for all farms.
I completely agree.
Every farm is unique.
Your farming practices, your herd size, where your
farm is located, and even the livestock species that
you raise - all these variables make parasite
control a pretty complex issue.
For example, you're running a beef cow/calf
operation here, so your deworming practices will
be different than if, say, example, you were raising
backgrounders.
Since you have sheep and goats, the FAMACHA test, a
simple evaluation of the lower eyelid, can help
you evaluate barber pole worm infections.
That seems simple enough.
Y'know, Rick, not all animals shed the same
number of parasite eggs.
About 20% of animals will shed about 80% of the
parasite eggs onto the field.
These animals are called "heavy shedders".
I had no idea.
What should be done about those?
Well, ideally, it would be great if we could identify
heavy shedders using a fecal egg count test.
Then, based on those results, they should
really be removed from the herd.
It won't be easy to get a fecal sample from every
single animal on my farm.
I understand.
It might be easier to identify the poor-doers in
your herd based on fecal egg count tests.
Then we can take those test results in
combination with your deworming history and work
together to develop a parasite control program
specifically for your farm.
Sounds like a lot to keep track of.... Well, you
already keep really good records.
Just make sure you keep track of the specific
animals you treat, when you treat them, what you
deworm them with, and their test results.
Just keep in mind that your overall goal
shouldn't be to keep your animals 100% parasite
free.
Healthy animals can have some parasites and still
thrive.
OK, well, let's get to work!
Sounds great!
As we've just learned, there's no
one-size-fits-all parasite control program for every
farm and every livestock species.
Talk with your veterinarian to develop a
program that's right for you.
Since resistant parasites can threaten your animals'
health and welfare, learning about parasite
resistance is the first step in combatting it.
Implementing parasite control strategies to
decrease the development of resistance will
positively impact your animals and reflect the
enjoyment and pride you take in their well-being.
Thank you....