Background and history

Abscesses are pockets of pus that contain dead cell material and large numbers of bacteria.

The bacteria usually enter the body through damage to the skin or via the external orifices.

They become walled off from the body tissues, or the bacteria are disseminated by the blood stream to develop abscesses elsewhere in the body. Near the skin surface they may become painful and may have an inflamed appearance. Identification of an abscess at slaughter can cause the possible condemnation of the carcass and hence loss of earnings, therefore it is important to identify and treat abscesses as soon as they are noted.

Haemorrhage into the tissues from a recently ruptured blood vessel, or a haemorrhage of long standing, is the only condition likely to be confused with an abscess. Such pockets of blood are called haematoma. In the case of a haematoma either pure blood or a very thin blood-stained liquid will be withdrawn. If they have been present for a long time a clot will have formed, in which case only serum or a clear liquid will be withdrawn.

Clinical signs

• Possibly emaciation and death.
• Small to large swellings.
• Pigs show pain / discomfort.
• Evidence of fluid – pus or blood in the swellings.
• Red skin may be ulcerated.
• Often damage evident to the skin.
• Lameness from spinal abscesses.

Diagnosis

Diagnosis is based on the clinical signs of abnormal swellings under the skin, especially with overlying scars. To confirm the diagnosis, feel and press the swelling to ascertain if the contents are fluid or solid and whether they are beneath the skin or deep seated. To examine the swelling more closely, restrain the pig by a wire noose or by heavy sedation (Stresnil 1ml/10kg), and sample the contents. This is carried out using a 10ml syringe with a 18mm 16 gauge needle attached. The needle is inserted at the lowest soft point of the swelling and fluid withdrawn. If it is an abscess a white, yellow or green substance of either a watery or a cheesy consistency will appear.

Causes

• Fighting (particularly when sows are grouped at weaning).
• Secondary infection arising from other conditions such as swine pox, porcine reproductive and respiratory syndrome (PRRS), pneumonia or tail biting.
• Small widespread abscesses in the skin (pustular dermatitis) may be seen following general illness, septicaemia and/or greasy pig disease.
• Damage to the skin by sharp objects in the environment. A typical example would be a neck abscess associated with worn and jagged metal on feeders.
• Trauma to feet, knees, tail.
• Teeth removal.
• Poorly administered injections.
• Chronic abscesses may form around joints following fractures.

Prevention

• Identify various projections and sharp objects in the environment. A typical example would be a neck abscess associated with worn and jagged metal on feeders.
• Long-acting antibiotic injections given at the time of damage will often prevent infection.
• Reduce fighting. More information on how to do this?
• Prevent tail biting and vice.
• Check injection procedures.

Treatment

• Treatment is aimed at draining the pus. Sometimes draining will occur naturally after the abscess bursts, but most require lancing or opening surgically. To do this make an incision approximately 15–20mm long at the lowest point particularly where it is soft and fluctuating. A sharp scalpel blade with only 15mm exposed is inserted into the abscess in a downward movement to open it up. Carry this out only when the sow is restrained. A quick controlled movement of the blade will cause little pain, far less than trying to infiltrate a local anaesthetic. The pus should be squeezed out and the interior washed using a syringe and sterile saline solution. Such a solution is made by adding five grams of salt to one litre of previously boiled water. The wound must be kept open for at least three or four days or until all the pus has drained out, otherwise the abscess may reform.
• Most of the organisms that cause abscesses in the pig are either penicillin or oxytetracycline sensitive.
• If the area is badly inflamed, squeeze into the hole an antibiotic cream (a cow mastitis tube is ideal) containing penicillin/streptomycin, oxytetracycline, amoxycillin or ampicillin.
• Treatment should be given by intramuscular injection – if the area is inflamed or the sow is ill. Medicines that could be used include:
  • Penicillin/streptomycin daily for 3–4 days.
  • Amoxycillin long-acting (LA) every other day.
  • Oxytetracycline (LA) every other day
  • Penicillin (LA) every other day.