Roundworms – A Year-round Problem

There are several possible internal parasites that can be found in turkeys. The most common culprit in the upper Midwest is a roundworm species the Large Round-worm, also known as Ascaridia dissimilis. This species has been a management hurdle for the turkey industry long before we moved from outdoor ranging to indoor barns. When infections with this nematode occur, most people have one of three responses.

1) worms are not a problem and the expense of treatment is not warranted.
2) worms are a significant problem, and ineffectual treatment is undertaken.
3) worms are a significant problem, and effective treatment is undertaken via close monitoring and usually with prescription.

We should gravitate to the third management option.

Controlling round worms is a must and eliminating them is possible. Control is necessary because although only heavily infected birds will show droopiness, emaciation and diarrhea, and possibly mortality, the primary damage from round worms is reduced efficiency of feed utilization, especially by the immature form, which produces the most severe damage.

Identifying the issue

For some background, adult worms are approximately one and a half to three inches long and are almost as wide as the diameter of an ordinary pencil lead. Thus, they can be seen easily with the naked eye. You can observe them by looking closely at the small intestine as early as a week after hatch, and they grow very quickly and feed voraciously. So once the problem is identified, immediate action is necessary.

The life history of this parasite is simple and direct. In the intestine of the bird, female worms lay thick, heavy-shelled eggs that pass in the feces. A small embryo develops in the egg but does not hatch immediately. The larvae in the egg reaches infective stage within two to three weeks. Embryonated eggs are very hardy and under laboratory conditions may live for two years. Under ordinary conditions, however, few probably live more than one year. Disinfectants and other cleaning agents do not kill eggs under farm conditions.

Birds become infected by eating eggs that have reached the infective stage. Our goal is to decrease the amount of egg contamination in the environment by cleaning. However, to be effective, we must also eliminate new eggs from being deposited. We do this with an effective deworming program that eliminates the worms before they have a chance to breed. The result is a reduction in deworming practices because we will eliminate the contamination, and we will realize increased feed efficiency at the same time with the program.

Methods for deworming
There are four choices for deworming. The following three options do not require a prescription:

1) Wazine (piperazine) in the water
2) Safeguard (Fenbendazole) in the feed
3) Safeguard in the water

The fourth option, which is Valbazen in the water, requires a prescription to obtain, and I prefer to use non-prescription methods.

Safeguard in feed
The most effective choice is Safeguard in the feed. The reason is simple – it is the most consistent way to get a constant application of dewormer to the birds. There is no settling out of the drug, and it kills both the immature and adult worms. Remember, turkeys are eating worm eggs at a constant rate, for an example let’s use 10 eggs per day. That means that in the 2-3 week life cycle of the worm, that translates to 210 worms of varying ages at the end of a 3 week period. Safeguard kills them all. In reality, a single roundworm female lays thousands of eggs per day – which makes the 10 eggs in our example a vast understatement of the problem, but it gives us a good idea. The draw back to Safeguard in the feed is that it works best with a two-tank system, because for 7 days the birds must only eat feed with Safeguard. Those who lack a two-tank system should manage the feed appropriately to be empty when the Safeguard feed gets there.

Wazine in water
Wazine works well at paralyzing the adult worms, and it does not require a prescription, but it does not affect the immature worms and if the adult worms are not expelled during the time of application, they will not die. They can crawl in the intestine so if they are not passed they will continue to be a problem. In this scenario, out of the 210 worms, you have possibly killed about 20 of the adults, and in 2-3 days more of the immature worms will reach adult status and are breeding for several days until the next treatment.

Safeguard in water
There is a formulation of Safeguard for water application. The molecules have been filtered to remove the larger pieces to allow for better waterline application. This vastly reduces the problem of the larger molecules creating issues with application. Although the feed application is preferred in my book – the water application with the new formulation is much more effective than it was before. It is also a bit more expensive, although in some cases it is the best option. This added cost is the reason why feed application is my preferred method over water application.

Valbazen in water
Another option is to get a prescription to use valbazen in the water. However, valbezen is a heavy molecule that settles out in water lines. This means it will only be effective in a percentage of the birds. If we speculate that 50% of the birds will be treated and have 0 worms, the other half have 250 because even though treatment has lasted several days, they have not been dewormed.
Commonly the best and more recommended option is to deworm your turkeys using Safeguard in the feed. If that is not a possibility then one of the other options can be used. It is important to remember the limitations and benefits of each option and decide which is the best fit for your program.

If you select Safeguard, there are some ways to work with the current systems.

• In one-tank systems, run the feed in the tank as low as possible, at least into the cone, and run the feed for nine days.
• In two-tank systems, empty one tank and refill that tank with feed containing Safeguard and feed continuously for seven days.
• It is vitally important to feed the Safeguard as indicated without interruption, if it is interrupted it will not be effective and it is too expensive to be unwisely utilized.

Timing is crucial
To determine when to run the Safeguard, teach your supervisors/helpers and/or yourselves to open up cull birds after the birds have been placed in the grow barns for three weeks. Check at least two, preferably three birds. Be sure that they have feed in the small intestine before opening. What is seen in the birds will determine when they must be dewormed.

If the worms are less than ½ inch in length, run the Safeguard in two weeks. If worms are an inch in length, deworming should happen within the week. Worms that are 1.5 inches in length were missed during the last inspection. Deworm birds with worms 1.5 inches long or longer as soon as possible. In cases where no worms were present, check the birds again in two weeks.

Once the Safeguard has been started, check the birds again in two weeks after it has finished running. The Safeguard kills all life stages of the worms, leaving us back to square one when it finishes running. A review of the worm history on the farm will determine how many times the flock will need to be dewormed. The longer we control the worms, the lower our egg burden will be. Do not be surprised by the need to deworm the first flocks more than once.