Parasitic worms and their treatment in ducks
Stock should be wormed routinely twice a year, and on any other occasion which necessitates it e.g. a bird seems ill, or is coughing. Call ducks do seem to suffer less from worms than geese, but any bird which is under-weight should be treated. Signs of worm infestation include loss of weight and blood staining around the vent. If a bird is wormed and placed on newspaper (in a show pen) for the night, then round worms may be seen in the droppings. If a sample of droppings is collected, the species of worm eggs present can be identified, under the microscope, by the vet. (See the article on worms in the Smallholder magazine - hyperlink above).
Worms which affect waterfowl come in a variety of forms.
Gizzard worm (Amidostomum)—more likely to be lethal in geese.
Gapeworms (Syngamus; Cyathostoma in geese) — make birds cough and, in extreme cases, will asphyxiate them.
Round worms—live in the gut (Ascarides). Occasionally seen in droppings
Caecal worm (Heterakis) which inhabit the caecae (two blind-ending extensions from the gut).
Also tapeworm and fluke.
Most of these worms use earthworms or insects as a host, and wild birds are carriers. So, however clean the environment, there is always is always a low parasite presence. The higher the density of stocking in an establishment, and the greater the length of time over which the land has been used, the greater the importance of regular worming.
The preferred wormer for birds is Flubenvet. This vermifuge can be obtained from your vet and the dosage for ducks should be checked with a vet because ducks are not mentioned on the label. The white powder comes in a 240g tub and usually has a very long use-by date. The product is licensed for birds, and kills all the parasites listed above, at the correct dosage. The dosage for geese and chickens is 120g on 100 kg of food (half the dosage for pheasant). This works out at 1.2g per kilo—easier to measure at one level teaspoonful (3.6g) per 3 kg. Check the weight of a teaspoonful on digital kitchen scales. The white powder adheres well to the pellets—better than to wheat—so just use pellets over the worming period. Don’t mix it with your hand because the powder sticks to your skin. Use a table spoon. The disadvantage of Flubenvet is that you have to feed it for a week, in the food, for it to be effective. So birds who are really ill, and not eating, cannot be dosed in this way. Another product and delivery as a drench (liquid down the throat) would be more suitable. Note that withdrawal times for Flubenvet are stated on the product label.
Ivermectin (pour-on) for controlling internal and external parasites is now available in 10 ml dropper bottles (800 μg/ml [0.8%] strength) from a vet. The recommended dosage is one drop on the skin once a week for 3 weeks. This dosage is for a pigeon and so is a suitable amount for a Call. It is marketed by Pharmaq LTD, Unit 15, Sandleheath Industrial Estate, Fordingbridge Hants SP6 1PA TEL 01425 656081. It is only obtainable through a vet. When using Ivermectin, observe the stated withdrawal time.
The number of worm species that Ivermectin kills is also more limited than flubenvet (tapeworm & fluke are excluded: V Roberts: Diseases of Free Range Poultry, Whittet Books Ltd ISBN 873580 53 3, page 55) but it is doubly useful in that it also systemically kills external parasites, such as northern mite, if used three times, spaced 7-8 days apart.
Note that it is recommended that birds should be wormed twice a year, outside the breeding season. Also, avoid the situation where birds get full of worms, and impacted; or, when the worms are killed, the toxins they release kill the bird.