Tetanus is a bacterial disease caused by the toxin produced by Clostridium tetani.
Tetanus occurs when C.tetani are present in damaged body tissue with lowered oxygenation. Puncture wounds such as nail pricks in horses' feet, penetrating splinters of wood, shearing cuts and lamb-marking wounds provide very good conditions for tetanus to develop. However, tetanus can also follow mulesing,dehorning or ring application and even wounds too small to be noticed.
Signs of tetanus occur from about four days to three weeks or longer after infection is established in a wound. The animal may have a stiff gait, "lockjaw" can develop and the third eyelid may protrude across the eye. The animal will usually go down with all four legs held out straight and stiff and the head drawn back. Convulsions may occur and the animal usually dies due to the breathing muscles becoming paralysed.