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Alpacas, unlike other grazing species such as sheep and cattle that become virtually immune to worms as they grow older, do not achieve a long-lived immunity to nematodes (worms). This may be an evolutionary outcome from the fact that they are used to a very expansive environment with relatively low stocking density up in the Andean mountains.
The alpaca is most susceptible as a youngster when eating grass, but is also at risk as an adult as they do not appear to form a solid immunity. I think we see more problems in adults because the challenge from worms is high. Alpaca owners often only have limited amounts of space available for their animals to graze and fields are grazed over and over, year-on-year, not getting time to rest. Therefore the build-up of worms can be high and the adults can succumb if the challenge is that great.
Signs of weight loss, with or without diarrhoea/mucky backsides, are the common presentations. Often if problems are seen with 'fly strike' (maggots hatched out on the skin of alpacas from fly eggs) there is often an underlying problem and commonly we find that the animal is debilitated by worms.
Worming should not be a routine treatment throughout the summer, as is advocated by the old school of sheep farmers. I would strongly recommend that dung samples are submitted to your local vet or laboratory, who will be able to tell you whether there is a worm burden (i.e. how many eggs per gram are found in the dung) and whether or not your animals need worming.
The decision to treat for worms is not just be based on the number of eggs in the dung, but also on the history and stocking density on the farm. Pasture rotation is the gold standard in worm control. Resting pastures, not just for a few weeks but for one to two years is the most effective way of reducing your worming need and the challenge on the alpacas.
Pasture rotation on an annual basis with cattle and crops on the land in the interim years is the best way of rendering the pasture clean of most worm eggs. Resting fields for a matter of weeks or months will still mean the pasture is contaminated with worms. Please ask your vet to discuss pasture rotation.
Dung collection or “vacuuming” as is performed by many horse owners is a good way to reduce the worm pressure on limited grazing space. Specific machines can be purchased to help the operation or the old fashion broom and shovel method can be used!
Worming products all come from three families of chemicals, although the trade names for these drugs vary considerably. Consult your vet to help you decide which the most appropriate treatment is. The three families are the Avermectins the Levamisoles and the Benzimedazoles (white drenches).
It should be noted that using some of these products at the normal cattle or sheep dose is inadequate for worm control in the alpaca. For example, “Panacur” should be used at 20mg/kg which is
4X the sheep dose. HOWEVER, “Levamisole” needs to be used at a lower dose than sheep and cattle, as toxicity is possible at twice the normal alpaca dose. Therefore one should consult your vet to ensure that you are using your worming products correctly.
In an emergency please telephone (01793) 522483 (24hrs).
Drove Veterinary Hospital, 252 Croft Road, Swindon, Wiltshire SN1 4RW.
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