Pressure sores develop on pigs (sows / boars) which are confined to a hard living area or in areas of close contact between pig and a hard structure. They are particularly common in animals which are paralysed (following streptococcal meningitis or bowel edema) or in those confined to stalls. The sores develop over bony prominences such as the point of the shoulder when subcutaneous fat levels can not protect the prominence.
- Causes of Pressure sores >
- Effects of Pressure sores >
- Diagnosis of Pressure sores >
- Treatment & Control of Pressure sores >
Causes of Pressure sores
The condition may be acute as in a paralysed animal or be chronic, in which case thickening of the skin over the area concerned may precede ulceration.
The formation of calluses or thickened skin may protect the area concerned and may be accompanied by the formation of adventitious bursae which are fluid-filled pockets between the callus and the pressure point.
These are most common over the bony prominences of the hock and are associated with lying on hard floors. Once pressure sores have formed, they may remain open or heal by scarring from the outside inwards. If infection occurs, they may continue to ulcerate until they reach bone and cause osteomyelitis or arthritis.
Effects of Pressure sores
Pressure sores are visible on the point of the shoulder in thin sows confined to a farrowing crate on an uneven floor. They appear as circular ulcers on the point of the shoulder and may be up to 5-10 cm in diameter. The ulcer often penetrates the skin and subcutaneous tissue but the base is composed of granulation tissue and bleeding is unusual. Reddened, swollen edges may indicate infection.
Smaller ulcers may be found on prominences on the feet, particularly if there are large gaps between slats or sows are confined to stalls on poor quality concrete. These ulcers tend to be smaller.
Linear ulcers form along the line of the neck tethers or where animals get their heads trapped between the bars of a pen. As soon as the pressure is removed, ulcers heal and healed ulcers may be seen in thin sows after weaning as hairless white scars. Calluses appear as thickened areas of skin subject to repeated rubbing and adventitious bursas appear as soft, fluctuating swelling over areas subject to pressure. Call both uses and adventitious bursae remain for a considerable time after the pressure is removed. Ulcers may be found on pigs within days of paralysis.
Diagnosis of Pressure sores
Care must be taken to examine both sides of an animal and to examine the feet, particularly in a lame animal. Paralysed animals must be turned to confirm the presence or absence of pressure sores. Sores must be distinguished from cuts and scrapes which may bleed or heal by scabbing. Calluses call on bony prominences are identifiable by inspection but adventitious bursae may require manipulation for detection as they may not be apparent in a standing or moving animal.
The presence of infection should be identified by the red colour and swelling of the surrounding tissue or the presence of black material or pus on the floor of the ulcer. Diagnosis of pressure sores relies on the fact that they heal by scarring and hair that does not reappear over an old ulcer.
Once the presence of ulcers is established, the causes should be sought. Lack of subcutaneous fat is a major contributing cause and should be obvious. A hard floor pen or piece of furniture is usually the direct cause. Restriction of movement is another obvious cause and paralysis and confinement to crates are also obvious.
Treatment & Control of Pressure sores
- The first priority is to remove the animal or from the hard surface area causing the pressure sores. This animal can be moved or provided with bedding.
- Animals with troubles which have reached the bone or a joint should be humanely destroyed.
- The sore should be assessed for infection and treatment given by injection, if infection is present.
- Topical antimicrobial sprays or dusting powders with wound, should be applied to eliminate risk of surface infection during healing.
- Thin animals should receive extra rations.
- Paralysed animals with pressure sores should be humanely killed as their presence is one of the criteria for immediate destruction.
- Animals to be Housed in spaces where troubles developed should be in good bodily condition and the hard surface responsible improved to prevent the problem.
- Poor flooring should be replaced and bedding provided where foot problems or shoulder troubles have developed.
- Animals to be confined in crates where pressure sores have occurred can be exercised daily to reduce the problem.
Prevention of adventitious bursas may require attention to housing or the provision of bed long before the problem appears. Paralysed animals should be well bedded and turned regularly to avoid pressure sores and killed if they can not recover.
