Deer and exotics pick up internal parasites or their eggs from the ground, then they reproduce internally.  To complicate things further, the animal will then shed the eggs in pens or pasture.  While deer and exotics can handle a certain level of internal parasites, once egg numbers pass a certain threshold internally, animals will begin to perform poorly and can progress to the point of morbidity if left untreated in your herd.  Issues with this are usually more common on years we have above average rainfall, like we are currently seeing in Texas. While there are many proven anthelmintics (expelling or destroying parasitic worms especially of the intestine) that can address parasites when they get above a certain threshold, I have had requests for some unusual methods to try to address parasite issues that I feel need to be addressed. While these may sound natural or holistic in nature, you could actually be doing more harm than good.

The two most common requests we have received have been for inclusion of diatomaceous earth (an organic powder that consists of the fossilized remains of tiny aquatic organisms, called diatoms) or copper oxide wire particles. While there is anecdotal data to support that these may work to decrease parasite numbers, there is also data to show how these ingredients can negatively impact health or performance. Remember, it is best to work with licensed veterinarians that you have a vet/client relationship with when there are issues with internal parasites. It is essential to determine which bug you actually have and what is the best course or action to remedy. Most cases will call for a proven anthelmintic. While these “natural” methods may help producers sleep better at night it is my intention to detail why each could be a cause for concern nutritionally and why don’t recommend or practice either in any of our facilities.

Diatomaceous earth is made from the remains of fossilized marine algae called diatoms. The product is mined and reduced to powder form. It has been used with some success as an insecticide, but its use as an anthelmintic has not been proven with any significance. The powder acts as tiny pieces of glass that tear the shells of insects and other arthropods. Many farmers add diatomaceous earth to the rations of their animals, among others, because it contains minerals and is relatively inexpensive.

Some claim that diatomaceous earth acts as a dewormer when added on a regular basis in the amount of 2% of the ration. Scientific tests on the subject are limited however and opinions of farmers are contradictory. Moreover, diatomaceous earth has no effect on lungworm and is not very appetizing. It is also a lung irritant. Given that the level of dust is already quite high in pens, diatomaceous earth does not seem appropriate when the animals are fed in captivity. The main motivation for adding diatomaceous earth to rations should not be to control internal parasites. Besides possible negative effects from respiratory issues, its effect on rumen bacteria and microbes is unknown, due to the sharp silica edges, it is also not what I would want going through the digestive system of any ruminant animal as it could be causing all kinds of issues that would lead to secondary infections. Basically it’s similar to finely grinding glass and putting it in the feed. Studies have not been done to determine the negative effects nutritionally on the digestive system of whitetail deer or exotics, but the physical characteristics alone should be enough to make you want to stay away from it. Inclusion of DE will skew mineral ratios due to the antagonistic nature of what it is composed of. It will also vary from one supplier or load to the next as it has no guaranteed analysis, so mineral package you are providing will be constantly changing.

The other request we have started to receive is for copper oxide wire particles. This is basically formulating toxic levels of copper being into a ration and why we will not do it. Copper oxide wire is also not an approved feed ingredient, so inclusion would most likely have to come from bootlegging it out of a cattle bolus which would be sketchy at best. While there is anecdotal data available that inclusion of high levels of copper oxide wire particles into the diet of a ruminant may lower the number of internal parasites present, none of the studies consider the negative nutritional effects that could come with feeding toxic levels of copper even for a short duration. Any time an antimicrobial like this is included in the ration, we are most likely going to negatively impact the rumen microbial environment which will most likely decrease performance more than the parasites do. The other considerations are the unknown down-stream effects that could be seen from a reproductive and immunity standpoint.

While both of these “treatments” are being recommended by some, I strongly recommend urging managers to stay away from both. We are basing this on the fact that there is limited nutritional data on response to either and we never want to recommend feeding anything we know will most likely negatively impact the rumen environment. We recommend going with proven anthelmintics that have sound nutritional data to back them up. Rattlesnake venom will most likely work on worms as well, but I wouldn’t use it in my feed!

Author: Bobby Deeds, Wildlife Specialist, Record Rack