A typical case of swollen head due to Clostridium novyi type A. (Photograph: Dr Johan van Rooyen)

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When swollen head (dikkop) disease rears its ugly head in a sheep or goat flock, it is usually a painful experience for both the animal and its owner. Stockfarm approached Dr Mari-Louise Nel, a veterinarian at CapeCross Veterinary Services in Cradock, to find out more about this Clostridium novyi bacterium-causing disease.

We also asked Dr Johan van Rooyen from Steynsburg Animal Hospital to provide some information that will help readers distinguish between the different forms and conditions of swollen head in sheep and goats (Table 1).

Head-butting rams

Sheep and goat rams are more susceptible to swollen head disease due to young rams’ tendency to fight one another. Dr Nel says this routinely leads to head wounds around the base of the horn, leaving the animal exposed to a bacterial infection caused by Clostridium novyi type A.

“This may cause severe swelling on the ram’s head,” she says, “which can descend into the animal’s neck and chest. At times a watery discharge seeping from the head wounds is also noticeable. Sick animals are listless and have little to no appetite, leading to weight loss and decreased production. Animals can even succumb in severe cases.”

Bacterial swollen head disease caused by inflamed head injuries usually occurs due to fighting among rams. Similar clinical symptoms, with severe swelling of the head, can also be attributed to the ingestion of poisonous plants such as ganskweek (or gansbossie) or Devil’s Thorn (duwweltjies), or even snake bites (Table 1). It is also possible to confuse swollen head and bottle jaw, which is associated with wireworm and liver fluke, when the swelling descends to the throat.

Table 1: Different conditions of swollen head in sheep and goats, and guidelines for treatment and prevention. (Source: Dr Johan van Rooyen)

Treatment and prevention

Bacterial swollen head disease can be treated to some extent, but according to Dr Nel, prevention is better than cure. “When it comes to treating the disease, your veterinarian will usually recommend penicillin and an anti-inflammatory agent. If the animal refuses to feed, giving meal or chopped lucerne, as well as keeping the animal sheltered from the sun and elements, will help.”

Swollen head as a result of plant poisoning. (Photograph: Dr Johan van Rooyen)

Preventing swollen head disease by administering a vaccine specifically developed for it is very effective. When sheep are first immunised, they receive two injections three to four weeks apart, after which they are immunised once a year, says Dr Nel.

Rams are normally immunised for the first time at the age of six months and then annually prior to the breeding season.” She says this is because rams can be quite combative during this time and the vaccine helps prevent swollen head caused by injuries. “The remaining sheep are immunised three to four weeks before being shorn.”

Bottle jaw due to wireworm or a protein deficiency. (Photograph: Dr Johan van Rooyen)

Other preventative measures could also be put in place, she says. This includes studying the social structure of the rams and separating the more dominant ones from the others. The camps in which rams are kept can be too small at times, leading to head butting and subsequent swollen head disease.

For more information, contact Dr Mari-Louise Nel on 048 881 0197 or cradock@capecross.co.za, or Dr Johan van Rooyen on 087 551 2783 or veearts.sdh@nokwi.co.za.

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