Deworming Deer and Elk

Safeguard and Panacur are just a couple of names for the anthelmintic (anti-parasitic) drug fenbendazole. It is available for oral administration (granules, crumbles & paste) and in some cases by prescription only. It is moderately effective in treating intestinal worms and lungworm but not particularly effective on adult liver flukes. Withdrawal times established in New Zealand range from 4-14 days. Suggested time is 14 days in the United States.

NOTE: AMDUCA – Animal Medicinal Drug Use Clarification Act – does not allow extra-label drug use (ELDU) of feed mixed anthelmintics, but does allow pour-ons, oral, injectible and water-mixed medications. None are approved for use in cervids aside from ELDU application. Canada has approved the use of Ivomec Eprinex for cervid livestock.

The most effective recommended dewormer for cervids is Cydectin (moxidectin) which is a pour-on. Label directions should be carefully read for this application to assure maximum effectiveness. (NOTE: not to be given to fawns with little body fat or emaciated adults.) Meat withdrawal times are not established in USA or Canada. NZ rates 21 withholding, and Australia approves 7 days. Suggested withdrawal interval (WDI) in USA is 21 days.

Levasol (levamisole) is not effective in deer species, according to Dr. Ken Waldrup of the Small Ruminant Practitioner’s Association and the Texas Animal Health Association. Valbazen (albendazole) dewormer should not be used on pregnant does, as it is known to cause birth defects.

Ivomec (ivermectin) is available in sub-cutaneous injectible form as well as pour-on. Veterinarians tell me that it is just as effective to give the injectible form orally. Promectin (generally used for horses) is basically the same thing. Ivomec Plus includes a liver-fluke additive. Ivomec F is NOT effective against liver flukes. Ivermectin’s withdrawal time is 28 days in New Zealand for the pour-on. No time established for sub-cutaneous. Suggested withdrawal here in USA is 56 days.

NOTE! It is recommended that in whitetail deer the dosages be doubled when treating for intestinal worms.

Ivomec and Cydectin deliver anthelmintics for control of gastrointestinal roundworms, lungworm, liverflukes in some forms, cattle grubs, sucking lice and mange mites.

October and April are months to routinely deworm deer. A repeat dose should be given in approximately 30 days. Even if only one animal is diagnosed, the entire herd should be treated with a preventive dose and afflicted animals should receive the treatment dose.

Fecal testing does not always tell the true story. Since first-round treatments may knock down the egg-laying process, second fecal samples tested may show “negative” infestation. Best to be safe rather than sorry and give the second round of dewormer to be sure.

Pour-on dewormers are usually most easily applied to tame deer. All others will have to be run through a chute or immobilized for the process of pour-ons or sub-cutaneous injection. Deer farmers must assess the risks of confinement or chemical immobilization against the benefits of deworming.

It is important to use preventative measures such as anthelmintic therapies coupled with pasture rotation to prevent repopulation after parasitic invasion. Quarantine of newly acquired animals for at least 30 days is also beneficial in determining if they are carrying unwanted parasites and preventing an outbreak in a clean herd. An ounce of prevention is worth a pound of cure!

Deworming should not be done on a continuing basis. Constant exposure to the anthelmintics creates parasites that are more and more likely to be resistant to the drugs.

Use only under the advice of your veterinarian, even if the medications are available over-the-counter.

By Thelma Morgan