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Discussion Starter · #1 · (Edited)
Ivomec is a brand name for the chemical ivermectin, a wormer used in the beef and lamb industries that has somehow become viewed as a potential go-to wormer in goat dairy operations, despite the fact that it is illegal to do so in commercial cattle dairy operations due to the long-term persistence of ivermectin residues found in the milk.

Milk Withdrawal Data
If you click this publication,
Look at Table 2 on page 2 for the milk withdrawal times for Ivermectin in goats.

Food Animal Residue Avoidance Databank recommended Milk Withdrawal Intervals (WDI) for ivermectin in Dairy Goats:

If dosed at a rate of 0.2 mg/kg of body weight on a standard breed goat it can be:
  • 40 days for SC (subcutaneous injection) [and no, that is not a typo]
  • 6 days for oral route of administration
If dosed at a rate of 0.2-0.4 mg/kg of body weight on a standard breed goat it can be:
  • 9 days for oral route of administration
Applied topically at rate of 0.5 mg/kg of body weight on a standard breed goat it can be:
  • 7 days for topical application

"Those withdrawal times are just guidelines though. FDA regards the complete absence of ivermectin in milk as the only acceptable situation, Van **** says, and any trace amount in milk, even if below the tolerance level established for other cattle, is a violation." "Finally, Van **** points out that even veterinarians cannot use ivermectin in dairy cows. Provisions for "extra-label drug use" allow veterinarians to use certain drugs for purposes or in classes of animals not specified on the label, but only if there is no approved, effective drug available for the intended purpose. In the case of parasite control in lactating dairy cattle, there are approved, effective drugs available with no milk withdrawal times, and extra-label use of ivermectin in [dairy] cattle remains illegal." "Dr. Tom Van ****, with Merial animal health, stresses that ivermectin is not approved for use in lactating dairy heifers or cows under any conditions." [In other words, if it is an animal intended for meat, that is the 'other cattle' that there is a tolerance level for, so there is a certain level of ivermectin residue acceptable for meat consumption, but not for milk, which must be completely free of any residue.]

Why? Because Ivermectin is very different than other wormers in that it is lipid soluble, and therefore can be problematic for a dairy animal being how it will stay stored in her body for an extended period of time. It is not legal to use in cattle dairies for this reason. And any trace of ivermectin found in commercial milk intended for human consumption is not allowed.

Metabolism rates vary from individual to individual, thus withdrawal times can vary according to each individual animal's ability to metabolize (process, detoxify, get rid of) the drug. An animal with a compromised immune system will take longer to metabolize a toxin thereby resulting in a longer withdrawal time. The FARAD guidelines represent the minimum withdrawal periods.

The FDA takes ivermectin residue seriously enough to fine commercial dairies for violations if found in the milk supply. Our government agencies are not known to be concerned about much, you can have cattle diseased with Johne's for example, and they are still allowed to remain in dairies producing milk for human consumption even though there are concerns that consuming such milk may be linked to Crohn's disease. So someone in the FDA must have reason to consider ivermectin residue in milk to be more dangerous than meets the eye.

An excellent article on why ivermectin for dairy animals is not a good idea: When Not to Use Ivermectin.

The Dangers of Ivermectin Use in Lactating Dairy Cows


Note: The FARAD recommended withdrawal times were based on studies that were performed on a standard size breed of goat. So for miniature breeds there haven't been any studies to provide any guidelines on a safe withdrawal time period and being how other drugs are supposed to be adjusted in dosage for minis that should be taken into consideration. Miniature breeds have a different metabolism rate so it isn't as simple as a mere body weight conversion. The reason I mention this is that the potential for overdosing a miniature breed of goat is high, and most vets are not well informed about this. Generally the higher the dose the longer it will stay in their system and thus equal longer withdrawal times.

Also of note, the recommended meat withdrawal times for ivermectin vary and can be shorter or longer in duration depending on the route of administration, but this discussion is about milk withdrawal so if anyone is interested they can check the above FARAD link for that data.


Further reading:

A study on Ivermectin use and resulting milk residues:

There was also a study done on how it impacts soil health and biodiversity: "Environmental impact of ivermectin excreted by cattle treated in autumn on dung fauna and degradation of faeces on pasture."
The Dangers of Ivermectin Use in Lactating Dairy Cows

When Not to Use Ivermectin


Some Little Known Facts about Ivermectin:
  • "Care should be taken when using ivermectin for treatment of nonlactating animals on a dairy farm. Treating dry cows can result in ivermectin residues in milk if insufficient time elapses between treatment and parturition"[1]
  • "Ivermectin is exceptionally potent, with effective dosages levels that are unusually low."
  • "Due to the high lipid solubility of ivermectin, this compound is widely distributed within the body."[2]
  • Milk containing traces of ivermectin has been found to be harmful for dog consumption
  • "Ivermectin also deposits in adipose tissue, which act as a reservoir that contributes to the long persistence of this drug in the body."[3]
  • "The response to ivermectin... can last for 6-12 months."[4]
  • Ivermectin is not approved for lactating animals.
  • Also, for humans "ivermectin is... not recommended for use in pregnancy or in children under 5 years of age."[5]

626 Posts
And yet i still am going to use it. Why change something thats been working great? If not ivermectin than what, herbal wormers? Going the herbal route just isn’t feasible when you have a large herd of 40 to 50 head.

76 Posts
Discussion Starter · #3 · (Edited)
I did not want to suggest any alternatives in this thread as the topic and focus was milk safety.

But I understand completely, some of the herbal ones can seem and sometimes be too expensive, depending on the product in question. Any product that is not effective is not worth much, regardless of the price. But how do you properly calculate economic savings of a product without also considering that it might have the potential to have negative health consequences?

I was just told that one of the links in the post wasn't working, and in it, Dr. Van **** does suggest alternatives that have less or no milk withdrawal period:

In my other thread on wormer effectiveness, I shared some info that was gleaned during a comparison trial. I did not share my own current practices. And my herd is not small by any means so I know what it's like to need - not just want but need - something that makes sense economically.

So without naming any brands, I will say that I buy my ingredients in bulk, mix my own and use that most of the year with great success, and suffice it to say that without intervention worms are a huge threat to goat health in this region. For more crucial times of year, in the worst months of wet, humid and hot weather, I use herbal products that I purchase, and also use that for does immediately after kidding. I have saved more money that way and have found that to be the most economical method for larger herds than any other method on the market that I am aware of, whether conventional, alternative or integrative. Anyone is welcome to PM me for more details, or read my other thread on herbal wormers.

I also supplement with copper (in the COWP form).

I know of some farms and goat breeders who are able to successfully control their herd's worm loads with COWP and lespedeza alone. For others using both works for the majority of the year. The ability to have this method work effectively in your herd will of course vary according to one's unique situation: weather conditions, climate, terrain, geographical location, feed quality, hay quality, pasture health, herd health and local worm populations. I don't want anyone reading this to get the wrong impression that this is possible everywhere. It's not. I also don't want anyone reading this take that to mean that you won't need to deworm your goats if you use COWP and lespedeza. That depends on the other factors listed above. Or that you don't need to monitor your herd's worm loads. You still do. For my herd, COWP and lespedeza are aids that I have found beneficial to their health, but I still need to deworm using herbal wormers. Personally I can attest to the fact that lespedeza can and does reduce and control barber's pole worm in dairy goats.

Lespedeza is around 16% protein and rich in calcium and some people add lespedeza pellets to the dairy feed ration (some add it but cut down on or lessen the other part(s) of the feed portion).

New research has proven that the previous recommendations for copper supplementation for goats were way too low. There are vets in my area that are using COWP on goat and even sheep farms with great success (though sheep require a lower dose of COWP, or 1/2 gram under 100 lbs, and after they reach 100 lbs. then 1 gram per 100 lbs. every 3 months). This has consistently resulted in far less need to use wormers, which in turn has led to economic savings. Regardless of which wormer is used, anything that decreases the need for it saves money.

And saving money without sacrificing food safety is one of the goals farmers strive for.
Indeed, saving money is one of our favorite subjects.

More on copper below:
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