It will come to no great surprise that the inner part of the pigs ear is responsible for balance. Therefore, any disturbance to this will affect the balance and co-ordination. A common cause to this is infection, initially of the middle ear, which exerts pressure on the balance. There are two distinct phases to the disease.
- In the early stages, damage is limited to the middle ear. The pig will frequently shake its head and as it stops the head will be left tilted to one side with the affected ear downwards. The head will then slowly return to normal. This phase is frequently ignored as the pig appears to recover.
- In the second stages, damage occurs to the inner ear and a permanent head tilt results. Head shaking will be frequent and the pig may be unsteady and tend to walk in a circle. In severe cases, the pig will have difficulty eating, drinking and competing with pen mates. And loss of condition will occur.
There are a number of potential causes of middle ear disease. Infection with organisms can occur either from the external ear canal following penetration of the ear drum, or via the eustachian tube from the oropharynx. The former is particularly associated with mange infestation in growing and young adult pigs, whereby rupture of the tympanic membrane is either a direct result of the mites or secondary to head shaking. Rough handling (pulling a pig by the ears) can also damage the ear drum and allow infection.
The Oropharynx is normally colonised by a wide range of organisms, which can spontaneously ascend the Eustachian tube, particularly in young growing pigs. However, inflammation of the oropharynx as part of any upper respiratory tract disease will predispose the animals to a gradual infection. This is particularly seen in association with swine influenza.
Antibiotics (penicillin or other antibacterial solutions) administered in the early stages for a prolonged period of five to seven days will bring about a complete cure. The longer you take to act the more pronounced the condition becomes and the more difficult it will be to treat and the pig may be left with a permanent head tilt but as long as it does not have a raised temperature, free from medication and is steady on their legs there is no reason why you can not carry it on to slaughter weight. Severe cases will almost certainly require euthanasia.