Actual Correct Dosage for Safeguard Dewormer for Chickens

[poiuytrewq]

Hello backyard chicken people,
I was browsing the web for the dosage of safeguard dewormer for my flock and was met with a bunch of conflicting info and what seemed to be incorrect info according to my calculations so I wanted to post this and maybe use it as reference for my future self should I ever need it.

There are a lot of posts regarding the dosage for chickens for Safeguard suspension dewormer. The consensus seems be a around 0.23ml or approximately 1/4ml per pound of body weight per chicken. I want to say that this is most likely incorrect. Now before anybody refutes me or starts an argument, please know that I'm not here to change your ways and if this has worked for your flock in the past then by all means continue. Sometimes experience is key and I'm just here to show you my calculations.

I know most people here use the Safeguard suspension 10% dewormer for beef, dairy cattle and goats as the Safeguard Aquasol is expensive and difficult to find. These numbers will be for people using Safeguard Suspension 10% dewormer.

First of, let me show why I believe the dosage of .23ml per pound of body weight to be incorrect. I know most people are using the 2.3mg/lb to calculate the dosage that's on the safeguard website. But that is actually quite misleading.
It's 2.3mg/lb for 100lbs.
There is 100mg of fenbendazole per ml of liquid.
It means it's actually 2.3/100 == 0.023ml/lb of body weight.
The prove is in the chart on the same site: https://www.merck-animal-health-usa.com/safe-guard/cattle/products/safe-guard-suspension
A goat weighing 25lbs would require a dosage of 0.6ml since 0.023 * 25 == 0.575 ~= 0.6

Now does that mean a chicken weighing approximately 5 pounds would require 0.115ml of the dewormer?
NO. It does not. Because the dosage for a chicken is actually 0.454mg/lb as seen on the Safeguard Aquasol page: https://www.merck-animal-health-usa.com/species/poultry/products/safe-guard-aquasol

I quote from the Safeguard Aquasol page:
"Chickens: Dose calculation:
The daily dose of 1 mg fenbendazole per kg BW (0.454 mg/lb) is equivalent to 0.005 mL Safe-Guard® AquaSol per kg BW (0.00227 mL/lb). The required daily volume of product is calculated from the total estimated body weight [kg] of the entire group of chickens to be treated."

Now as it states above, when using safeguard Aquasol, the dosage is 0.00227ml/lb of the chicken's body weight. But as I said before, most people aren't using Aquasol, they're using the 10% suspension meant for cattle and goats. The main difference that I've seen between the two safeguard products is just the amount of fenbendazole per ml of liquid.
Safeguard Aquasol contains 200mg/ml.
Safeguard Suspension 10% contains 100mg/ml.
The cattle dewormer is half as strong as the Aquasol. Thus for chickens the dosage to administer is 0.00454ml/lb.

Here is also some more math if it feels like it shouldn't be this simple.
For the site to say that 0.00227mL/lb of Aquasol is equivalent to 0.454g/lb of 1mg fenbenazole, they had to divide 0.454 by 200 since Aquasol contains 200mg/ml of fenbenazole.
0.454 / 200 == 0.00227mL/lb
Using this formula, where the 10% suspension contains 100mg/ml.
0.454 / 100 == 0.00454mL/lb

Also I know the dosage for the 10% suspension and Aquasol both seem quite low but it you refer back to the Aquasol website, it states to use 25ml per day for 11,000lbs worth of birds. The 10% suspension is also only using a mere 0.6ml for a goat that weighs 25lbs. So 0.23ml/lb for a chicken is actually a very very high dose.

You can also read the labels for both medications here for more details: https://merckusa.cvpservice.com/product/basic/view/1047396?key=label
https://merckusa.cvpservice.com/product/view/1047550

TLDR: The dosage for chickens using Safeguard Suspension 10% is 0.00454mL/lb of body weight

 

[casportpony]

Welcome to BYC.

The 0.23 ml per pound dose (50 mg/kg) is correct if you want to treat *all* worms including capillary worms. Note that egg withdrawal is recommended.


This low dose of 0.00454 ml (1 mg/kg) you are referring to is also correct, but it's for treating large roundworms & cecal worms. It will *not* treat capillary worms, gapeworms, etc.

The correct dose depends on what worms you want to treat.


From a vet:

---

 

[poiuytrewq]

0.23 ml per pound dose (50 mg/kg)

low dose of 0.00454 ml (1 mg/kg)

can I ask what the numbers in the parenthesis indicate? Is it supposed to be the concentration of the medication like how Safeguard suspension 10% has 100mg/mL of liquid or is it suppose to be the metric version and it's saying that 50mg/kg is the equivalent of 0.23ml/lb?

 

[casportpony]

When medication is given, the dose list is almost always written as mg/kg. which means number of milligrams per kilogram to give.

The low dose you are talking about is 1 mg/kg, right?

The two types of fenbendazole you are talking about are Aquasol & the coat/cow/horse stuff.

Aquasol is 200 mg/ml. That means there are 200 mg of fenbendazole in 1 milliliter.

The coat/cow/horse stuff is 100 mg/ml. That means there are 100 mg of fenbendazole in 1 milliter.

Still with me?

One has to ask oneself what worms one wants to treat, pick the dose that treats those worms, and then do a little math.


The math formula is *always* the same:
Weight of bird in pounds, divided by 2.2 (converts to kg), times the dose, divided by the number of mg in one ml.

If you are sure your 5-pound hen does not have any worms other than large roundworms or cecal worms:
5 / 2.2 x 1 / 100 = 0.0227 ml

If you think your 5-pound hen might have capillary worms:
5 / 2.2 x 50 / 100 = 1.136 ml

 

[poiuytrewq]

I think I see the issue now and I believe it's caused by the discrepancy between the amount of fenbendazole per mL vs the amount of liquid per mL.

When converting from mL to mg, you're supposed to multiply by 1000 and the density of the liquid. The density of water is approximately 1g/cm^3 or 1g/mL. So we usually just say that there is 1000mg/mL.

Now the tricky part appears here, at least for me.
In a bottle of Safeguard for cattle/goats, there is 100mg of fenbendazole per mL. BUT this does not mean there is 100mg of LIQUID per mL or does it?

Safeguard dewormer for cattle/goats is a 10% suspension. Meaning only 10% of the stuff inside is the fenbendazole and when you use it, you shake it up and hope the stuff you need had been distributed properly.

Let's say you have the 125mL bottle of dewormer, this technically means there is 12,500mL of fenbendazole in the bottle right?

You can see how this is confusing right?

The amount of liquid and fenbendazole isn't a one to one ratio so when calculating the dosage, a person is asking how much liquid to give per pound of chicken but the answers feel like they're indicating how much fenbendazole to give.

I'm not saying the dosage of ~0.23mL/lb(rounded up tp 0.25mL/lb) is incorrect and as you've mentioned, some worms require a bigger dose. But as I mentioned in my original post, a cow at 100lbs only requires 2.3mL of the liquid which equals to 0.023mL of liquid per pound of cow. Even when a bigger dose is needed, how could it be 10 times more per pound of bird than it is per pound of cow.
In my head, 0.23mL of fenbendazole per pound of bird makes sense but 0.23mL of liquid which should contain 23mg of fendendazole per pound of bird doesn't sound right.

And please by all means, correct me if I'm wrong or misunderstanding anything. I do want to wrap my head around this somehow.

 

[dawg53]

Chickens have a faster metabolism rate than mammals which require a higher dose of the wormer in order to be effective. Benzimidazoles are poorly absorbed into the bloodstream and mostly excreted unlike in mammals.
Birds are a different ball game when it comes to administering wormers.

 

[RubyLady]

Forgive me, but I have dyscalculia so the math is lost on me.

I found 2 roundworms on my oldest hen's fluffy butt this morning when I noticed she wasn't acting normally and seemed sick. She's maybe 4 years old. She's the only one acting sick out of 13 hens. I clean the poop out of the coop every morning and haven't seen any worms, but they've all been lying around in warm humid conditions because they can't free-range due to foxes. Good worm weather...

I used 4 ml of the goat SafeGuard in 1 gallon of water (as recommended on many YouTube channels) and split it into two rubber dishes. I am supposed to do this for 5 days.

I am not able to wrangle and administer wormer individually by myself (which I see would be better) due to my arthritis.

Can some of you math people help figure out about how much each hen is likely to injest via the water, especially if I am stirring it up frequently during the day or giving them a fresh batch a couple of times a day? it didn't seem to settle at all and was still well mixed an hour later. I shook it up in a gallon jug, I didn't just stir it.

Thanks.

Edit: I should also say, they usually have two 1 gallon buckets to drink from and they never even drink half of that in one day. I have 13 laying hens.

 

[RachaelV123]

Forgive me, but I have dyscalculia so the math is lost on me.

I found 2 roundworms on my oldest hen's fluffy butt this morning when I noticed she wasn't acting normally and seemed sick. She's maybe 4 years old. She's the only one acting sick out of 13 hens. I clean the poop out of the coop every morning and haven't seen any worms, but they've all been lying around in warm humid conditions because they can't free-range due to foxes. Good worm weather...

I used 4 ml of the goat SafeGuard in 1 gallon of water (as recommended on many YouTube channels) and split it into two rubber dishes. I am supposed to do this for 5 days.

I am not able to wrangle and administer wormer individually by myself (which I see would be better) due to my arthritis.

Can some of you math people help figure out about how much each hen is likely to injest via the water, especially if I am stirring it up frequently during the day or giving them a fresh batch a couple of times a day? it didn't seem to settle at all and was still well mixed an hour later. I shook it up in a gallon jug, I didn't just stir it.

Thanks.

Edit: I should also say, they usually have two 1 gallon buckets to drink from and they never even drink half of that in one day. I have 13 laying hens.

I'm curious about this because I also struggle with some of my chickens. Some I have no problem administering meds but others will fight me to the death it seems like, so if it would actually work in water, I'd love to know this as well.

 

[RubyLady]

I'm curious about this because I also struggle with some of my chickens. Some I have no problem administering meds but others will fight me to the death it seems like, so if it would actually work in water, I'd love to know this as well.

I did use the SafeGuard for goats in their water, but decided to also get a dose of the paste into the one I knew had roundworm.

She's the oldest and when I let them all out into their yard in the morning, she's the last. I was able to let them out and keep her in easily. Then I gave her a small bit of hard-boiled yolk mixed with the paste and she ate it right up. Easy peasy!

I'm going to do the follow-up round the same way with all 13 to make sure they are getting dosed. Just let one bird out at a time into the fenced yard, feed them their egg yolk and paste, and let that one out to free-range. That way I have only one bird to deal with at a time and no one pushing in and eating the other hen's dose.

Maybe that will help you. I have the same issue. Half of mine will sit on my lap and let me do anything and the other half is not so compliant. But they all love hard-boiled egg yolk!

 

[RachaelV123]

I did use the SafeGuard for goats in their water, but decided to also get a dose of the paste into the one I knew had roundworm.

She's the oldest and when I let them all out into their yard in the morning, she's the last. I was able to let them out and keep her in easily. Then I gave her a small bit of hard-boiled yolk mixed with the paste and she ate it right up. Easy peasy!

I'm going to do the follow-up round the same way with all 13 to make sure they are getting dosed. Just let one bird out at a time into the fenced yard, feed them their egg yolk and paste, and let that one out to free-range. That way I have only one bird to deal with at a time and no one pushing in and eating the other hen's dose.

Maybe that will help you. I have the same issue. Half of mine will sit on my lap and let me do anything and the other half is not so compliant. But they all love hard-boiled egg yolk!

That's a really good idea, thank you! I swear, one of my roosters knows when I'm trying to give him meds and won't eat anything I try giving him. It could be his favorite snack and he still won't touch it. Smart little monster he is.