Damage to the feet, joints or muscles of the leg or to nerves controlling the legs can cause pain in lameness as can any of these sites. Erosion of the sole, and bruising on the heels of the accessory digits and erosion of the knees in sucking piglets occurs on poor quality flooring. Effects of lameness are high culling rate, difficulty standing or walking.
- Causes of Lameness >
- Effects of Lameness >
- Diagnosis of Lameness >
- Treatment & Control of Lameness >
Causes of Lameness
Infection enters and can give rise to septic arthritis of the joints of the foot or to synovitis (inflammation of the joint linings). Vesicle (blister) formation in foot-and-mouth disease and swine vesicular disease causes intense lame ness and biotin deficiency can cause lame ness through breakdown in the hoof horn. Foot infection causes footrot in older pigs. Broken bones can cause lame ness as can the loss of the articular cartilage in epiphyseolysis or pelvic damage in the sow and inflammation of the bone (osteitis proliferative) in gilt or sows kept on slippery floors. Joint problems are caused by infection by streptococci, erysipelas or by mycoplasmas and developmental damage as part of the osteochondrosis complex (leg weakness). Adventitious bursitis can cause lame ness and results from hard flooring. Muscle damage can result from Vitamin E deficiency and nerve damage can be physical, resulting from infection (Teschen / Talfan) or nutrition (pantothenic acid deficiency).
Effects of Lameness
Lameness is a failure of the pig to walk normally. Mildly affected pigs have disturbed gait with swaying of the hips or the legs may be bowed.
Pigs which are lame may stand with the back arched, all four feet tucked under the body and the head down to reduce the weight on the feet. The snout may be resting on the ground. Movement is difficult lame pigs and rest frequently, find difficulty in rising and are reluctant to do so.
Lame pigs or sows may not stand for service and collapse easily. Boars may not serve. Lame pigs squeal if sudden if sudden movement results in pain especially if there are broken bones, acute infection or nerve damage.
Pigs with a damaged leg will not place weight on it and hop on the remaining legs sound. Damage to the feet results in snatching the affected foot off the ground or resting it, down to but not placing weight on it.
Lame pigs frequently lose condition as a result of pain or of the underlying disease where infection is responsible, can not compete with others for food or for social position and often lie apart from the group. Lameness is a frequent reason for culling.
Diagnosis of Lameness
Lameness is usually obvious from inspection, but inspection must be thorough. Recumbent pigs must be made to rise and watched walking alone and in good light. Posture (hunched back, head down) may draw attention to lameness in a group as may squealing on movement, poor bodily condition or the presence of skin scratches on pigs which have lost social position.
The site and cause of the lameness requires more detailed examination. When there is lameness or failure to bear weight on a leg, it should be examined systematically, beginning with its appearance, feeling the upper parts, moving the joints for evidence of pain and examining them for signs of heat or swelling (signs of arthritis) and finally examining the feet. These may require cleaning and even trimming of overgrown horn.
More detailed examination can be carried out using nerve blocks, X rays and ultrasound and at post-mortem examination or slaughter. Other pigs in the group should be examined where lameness is widespread, as disease such as erysipelas may be present. The severity and likely duration of the lameness must also be assessed as lame animals cannot be transported in many countries and must be treated or culled on farm.
Treatment & Control of Lameness
Treatment depends upon the nature of the condition present and the severity of the lameness.
- Animals with broken legs must be killed immediately and those with lameness which will not resolve should be culled.
- Infections may be treated with an antimicrobial to eliminate the infectious agent, but animals which do not respond should be re-assessed and culled as unlikely to recover.
- Vesicular disease like foot-and-mouth disease must be notified to the state veterinarian.
- Overgrowth of the hoof horn can be trimmed and local infections treated by injection with antibiotic and use of antibiotic spray or disinfectant footbaths.
- Infected single claws may be removed under local anaesthetic.
- Lame pigs under treatment require support and should be protected from their group, placed on a soft floor of straw or deep shavings and given adequate food and water.
Control also depends on the condition. Erysipelas and Glässer's disease can be prevented by vaccination and streptococcal arthritis and mycoplasmal lameness by antimicrobial treatment of the group.
Injuries to the foot and adventitious bursitis can be reduced by rearing on soft bedding or correctly-designed flooring with pencil edge slats, polypropylene coatings for perforated floorings and round edged aggregate in concrete. Bedding must not remain wet.
