- Intestinal torsion (redgut) (fatal in 2-3 hours)
A New Approach to Worming:
Do you worm your animals?
How often do you worm?
What wormer do you use?
Do you know why you are worming?
Do your animals seem to feel better after you worm them? How do you know?
Do the skinny ones or the fat ones seem to benefit the most?
FAMACHA theory: Uses the least amount of wormer to benefit the most
animals and save you time and money.
The enemy: Haemonchus contortus. A very small worm (about the
size of a goat hair) that lives in the abomasum (fourth stomach) and sucks
blood. Goats can lose up to a cup of blood per day. The youngest animals are
the most at risk.
Where do sheep and goats get these worms? The worm larvae (baby worms)
are on the pasture. Animals pick up the worms by grazing. These worms can
live on the pasture for 3 months in the summer or 6 months in the winter.
Each worm (female) lays 5,000 eggs PER DAY. Each animal has about 300
worms. Each animal can deposit 1.5 MILLION eggs onto the pasture EVERY DAY.
A herd of 30 goats can deposit 1 BILLION eggs onto the pasture in 3
It takes less than 3 weeks from the time a worm larvae is eaten off the
pasture until it becomes a blood-sucking, egg-laying adult.
Giving wormer to an animal only helps that animal for 3 weeks and does
nothing for the worms that are on the pasture.
Faced with these odds, worming animals on a regular (or irregular) basis
might temporarily help a few animals but it doesnít really help the total
Actually, worming animals as we have been doing is making the situation
worse because the worms are very good at becoming resistant to the wormers
Rotating wormers was a good idea at the time, but in practice has
actually caused worms to become resistant to more wormers rather than the
other way around. There are a dozen or so wormers on the market, all with
different-sounding names. What most producers didnít realize was that you
had to switch classes of wormers, not just wormers.
There are only 3 classes of wormers. Worms develop resistance not
just to one wormer but to all the wormers in that class.
- Benzimidazoles: (white wormers) Panacur, Safeguard, Valbazen
- Avermectins: Ivomec, Cydectin, Dectomax, Eprinex
- Imidathiazoles: Levamisol, Tramisol, Pyranted, Morantel, Strongid
There is a test called DrenchRite that uses a pooled sample from 10-12
animals and tests for resistance to all 3 classes of wormers. It is
available through Dr. Kaplanís lab in Georgia. This should ideally be done
every 2 years to make sure you are using the right wormer for the job.
In the past, resistance was not as much of a problem because there was
always a new and better drug in the pipeline to save the day.
There are no new drugs in the pipeline!
In Georgia, 90% of the worms are resistant to Panacur, Valbazen and
Ivermectin. 30% are resistant to Levamisole. Resistance is developing to
Cydectin. Some farms are down to their last usable wormer.
In tropical areas such as South America, worms are 100% resistant to
every known drug and they lose 20% of their animals every year
Where does this leave us? If we continue doing what we are doing, we may
have no wormers available to use in the near future.
What can we do?
- Extend the usefulness of the wormers that we have
- Find other ways of keeping our animals from getting sick from worms
- Develop other strategies for controlling worms, such as fungi that
trap worm larvae, copper boluses in the rumen and vaccines.
We need to accept the fact that we may never eliminate all of the
worms from our animals.
A low number of worms are actually a good thing. Animals develop
resistance to the worms that they have and donít let any more get
- Resistance can be natural; some animals are just stronger than others.
- Resistance can be genetic; they pass their resistance (or lack of) to
- Sheep have more natural resistance than goats.
- Keeping animals healthy will help them to develop their resistance.
- Managing the pastures so the animals pick up fewer worms.
20-30% of the animals in your herd carry 80% of the worms. (These are
probably your skinny animals)
How else can you tell which of your animals have the worms?
- Have your veterinarian do a fecal
Developed in South Africa where worms are a huge problem and people
have no money and no education. It was developed to be easy to use and use
the least amount of wormer.|
Since Haemonchus worms suck blood, the animals with the most
worms will have less blood and be more anemic.|
The level of anemia can be determined by the pinkness of the color in
the inside of the eyelid. FAMACHA is a color chart that relates the eyelid
color to whether or not the animal is anemic enough to need treatment.|
It really is OK to NOT worm your animals.
When you give wormer to an animal, you only kill off most of the
worms. The worms that are left behind will produce offspring that are also
resistant to the wormer. Eventually, the only worms left are resistant and
your wormer doesnít work any more. If you under-dose an animal (give less
than the full dose), resistance develops even faster.
Only worming some of the animals lessens the chances of the worms
When you give wormer to an animal that only has a few worms that it may
be getting resistant to, you upset the balance in that animal, possibly
causing it to pick up more worms the next time around.
By not worming an animal, it is still going to deposit some worm
eggs onto the pasture, but those worms will be sensitive to
your wormer the next time around.
Having some sensitive (untreated) worms on the pasture dilutes out
the resistant worms. The next time you need to worm an animal again,
that wormer will be more likely to work for you again
Pasture Management: What you can do to help your animals pick up
- Worm larvae get dried out easily, so they stay close to the ground in
- If goats are grazing very short pastures (July and August), they are
going to pick up huge amounts of worms.
- If the grass is taller, they donít pick up as many worms. You can do
this by grazing fewer goats in a given area or rotating pastures to let
the grass catch up.
- Goats actually prefer to browse, or eat tall weeds. This is natureís
way of protecting goats from worms.
- Horses and cattle donít share worms with sheep, goats, llamas and
alpacas. Horses and cattle will "vacuum" the sheep and goat worms off the
pasture, leaving less for the goats to pick up.
Part of the problem we are having with worms is that we have been
selecting for "wimpy" animals and relying too heavily on our wormers to
deal with the problem.|
When you select herd replacements, choose animals and their offspring
that have stayed fat and healthy without needing to worm them.|
If you have animals that are always skinny and have pale eyelids and
always need to be wormed, do you really need these animals on your farm?
They are costing you money because you have to worm them more often (and
the worms are eating all your feed). They are also putting more worms onto
the pasture for your other animals to pick up.|
When you purchase new animals, donít buy skinny, wormy animals!
Check their eyelid color and body condition.|
When you bring animals home, keep them separated for at least 10-14
Try to keep them off pasture; a stall or dry lot is best. Do
everything you can to get rid of their worms before you mix them with your
other animals. Worm them with 2 or 3 wormers from different classes at
once (Ivomec and panacur, maybe cydectin) and check a fecal in 10-14 days.
This quarantine period will also keep the new animals from spreading other
Smart Drenching Worm like you mean it!
© 2006 New Ross