Tetanus 'Klem-in-die-kaak' in Angora goats
By Dr Mackie Hobson BSc(Agric),BVSc

1. Diseases

Tetanus is occasionally seen in Angora goats after castration using an elastic ring but infection through any penetrating wound such as after shearing or difficult birth, by the bacteria Clostridium tetani, is possible.

Necrotic (dead) tissue creates the necessary anaerobic environment for the bacteria to grow and produce the potent neurotoxin which causes the rigidity and muscle spasms seen in the disease.

Where does the infection come from?

The spores of C. tetani are present in soil, dust and faeces of the goat. The bacteria is part of the normal intestinal flora of the gut and plays so plays a role in the spread and concentration of the spores in the environment and hence why areas around ‘kraals’ and sheds is usually the most contaminated area.

How long is the incubation period after infection?

Several factors influence the length of the incubation period of tetanus so the incubation may be:

• As short as 3 days but usually 1-3 weeks
• It is possible for the spores to remain dormant in the wound for a long time (months to years)

Clinical signs:

Clinical signs usually first appear in the head and neck region and then the upper body before extending to the legs.

• Stiffness, mild bloat, wide based stance, stiff ears, ‘grinning’ facial expression may be seen in the early stages.
• Stiffness of muscles is seen especially the goat is stimulated by handling or noise.
• Spasms develop in all muscles when stimulated.
• Prolapse of 3^rd eyelid, spasm of nostrils, tail
• Stiffness of hind legs common
• Kids may have a ‘grinning’ facial expression due to the contraction of facial muscles.
• The goat will fall down in lateral decumbency and go into spasm before showing (head pulled back over shoulder).

The goat will usually die 12-72 hours after signs are observed. Fatality usually 100% after clinical signs are shown.

In cases where very low doses of toxin occur it is possible the condition may be prolonged up to 10 days and  it is possible (unusual) for the goat to recover.

Diagnosis:

This is usually based on the history and clinical signs.

The identification of the bacteria from smears and isolation of the bacteria from cultures of the wound is possible but rarely done.

Are there other diseases with similar clinical signs

Plants poisoning by:

• Sarcostemma viminale
• Cynanchum
• Euphorbia mauritanica

Recumbent goats suffering with CNS lesions (Thiamine Vit B1, Pulpy Kidney, Heartwater)

These can be excluded by the absence of prolapse of 3^rd eyelid and rigidity of leg muscles.

Treatment and prevention:

Vaccination is important in the prevention of the disease and most broad based clostridial vaccines will contain tetanus. It is important to maintain immunity by following the manufacturers guidelines. See our website for multiclostridail vaccine options: https://www.angoras.co.za/page/vaccine_cover_1st_addition#116

Wounds should be treated at time of shearing and castration. Clostridium tetani is susceptible to penicillin, tetracyclines which most Angora farmers will have available in injectable form or topical sprays.

It is important to keep all shears and surgical instruments as sterile as possible,

In an outbreak it is possible to give the healthy kids the tetanus antitoxin which provides protection for 3 weeks.

Once clinical signs develop humane euthanasia is considered the best option as prognosis is so poor. Valuable animals can be sedated, placed in dark room and treated with muscle relaxants. The wound can be surgical debrided and treated with penicillin. Expensive antitoxin can be used. Treating the goat showing clinical signs may cause unnecessary suffering.

References:

Infectious Diseases of Livestock (J. Coetzer, G.Thomson and R.Tustin)