Lameness in Farrowing Pigs

Neonatal septic polyarthritis, a common cause of death and culling in suckling pigs, is due to various facultative and specific pathogens that cause localized infections that precede septicemia.

Healthy pigs often compete for teat order and paddle with their legs while suckling, causing skin abrasions of the carpi or coronary bands. Bacterial infection often becomes established under the resulting scabs. Poor hygiene at tail docking, ear notching, or castration, as well as careless clipping of needle teeth, can also result in localized infections.

Infected wounds can lead to bacteremia in pigs, with organisms accessing the synovial membrane and polyarthritis an outcome. Microorganisms can also gain entry to the circulatory system via the tonsils or oropharynx or as a result of an ascending omphalophlebitis.

Pigs with exudative epidermitis are also prone to polyarthritis; however, this susceptibility may be a reflection of the same type of skin damage discussed above.

Pigs with neonatal polyarthritis become lethargic, painful, and less competitive to suckle. Joints become swollen, painful, and warm, with severe lameness affecting one or more limbs. With time, the soft, fluctuant joint swellings become firm. At necropsy, creamy or green pus is found in and around swollen joints (particularly the elbows, carpi, stifles, and hocks), in the umbilical stalk, and sometimes over the meninges or in the fissure between the cerebrum and cerebellum.

The umbilicus should be always be examined to see whether it is hard and swollen and a possible portal of entry.

Organisms isolated from baby pigs included streptococci (eg, Streptococcus suis), staphylococci, Trueperella pyogenes, Escherichia coli, Actinobacillus suis,  and, less frequently, Glaesserella parasuis, Pasteurella multocida, or Erysipelothrix rhusiopathiae. Affected pigs that survive and are weaned often become runts that fail to thrive in the nursery.

Treatment of neonatal polyarthritis is based on bacterial culture and antimicrobial sensitivity profiles, as well as on applicable regulations on product use. Antimicrobial treatment must be initiated early in the course of the disease to be effective, and treating all pigs in the group at risk may be prudent, especially if S suis is implicated. Penicillins have been the drugs of choice, depending on the causative agent and sensitivity.

Regardless of the cause of a local infection, if septic polyarthritis is an ongoing problem, it is important to observe the practices used in farrowing rooms and look for opportunities for improvement. An all-in all-out flow of pigs is important, and scrupulous hygiene in farrowing crates helps to decrease environmental contamination and the incidence of neonatal polyarthritis.

Prevention of neonatal polyarthritis may be difficult because most types of floors, including those bedded with straw, can cause skin abrasions. Plastic-covered woven wire, which provides a smooth, relatively soft, self-cleaning floor, may help; plain woven wire is similar, if it is smooth. If replacement of flooring is not economically viable, sections of clean, soft carpeting may help minimize skin abrasions.

Separate instruments should be used for teeth and tail clipping, and they should be cleaned and disinfected between pigs, preferably using a dry paper towel. Soaking instruments in contaminated disinfectant solution between pigs or litters promotes contamination and infection.

If teeth are not clipped or if there are sharp remnants of clipped teeth, pigs that suckle aggressively can lacerate the faces of other pigs, resulting in pyoderma.

Castration equipment must be kept sterile and sharp. If tail stumps are infected, antiseptic solution may be used as a spray to improve hygiene.

Piglets are more prone to neonatal polyarthritis under the following conditions:

• The litter is from a gilt. Colostral protection against this syndrome and other infectious diseases of baby pigs increases as a sow ages.

• The litter is large. Lesions on faces and forelimbs are more common because the pigs have to compete more to suckle.

• The nursing sow has hypogalactia or agalactia. Piglets have more forelimb lesions because they must spend more time nursing.

Neonatal foot lesions fall into two main categories: either the sole or heel is damaged by the floor, or the hoof wall is traumatized because the sow stands on a piglet’s foot or a piglet gets its foot trapped in the flooring.

Bruises or lacerations develop on either the sole or the heel. The lesions are associated with worn and rough floor surfaces and with floors that have either solid or perforated surfaces. Rough flooring can also cause bruising in soft tissue below the hoof wall. If spaces between slats are large, digits can be entrapped, and lameness results from bruising or infection at the coronary band.

Pigs on expanded metal floors can incur heel and wall injuries leading to loss of accessory digits. Second and third digits may be damaged as the pigs thrust with their feet during suckling and catch their toes against sharp metal edges. Sharp spicules on woven wire cause lacerations and predispose the pig to infectious laminitis and polyarthritis.

Prevention is based on selecting floors that minimally injure feet or skin. Because of similarities with infectious polyarthritis, the approach to treating and preventing foot lesions is similar (see above). Improved hygiene within the environment may help decrease septic laminitis and allow injuries to heal.

Splayleg (or spraddle leg) is precipitated by weakness and immaturity of skeletal muscles at birth that is due to impaired myotubular development. Forelimbs, hind limbs, or all four limbs may be affected such that the piglet either walks with difficulty or cannot stand.

Splayleg appears sporadically in litters, and typically only a few pigs in a litter are affected. A hereditary component has been reported in European Landrace Swine and, to a lesser extent, in Large White Swine. Male, premature, and small pigs, as well as pigs from older sows, seem especially susceptible.

Deficiencies of choline, methionine, and thiamine in the sow’s diet may precipitate splayleg, and zearalenone toxicity via the sow’s milk has been implicated; however, the exact cause is controversial.

To varying extents, pigs with splayleg are unable to move around and they die, either because the sow crushes them or because of hypoglycemia. Alternatively, skin and foot abrasions develop, predisposing the pig to arthritis, polyarthritis, or pododermatitis and osteomyelitis of the digits.

Timely management practices are essential to ensure that pigs can feed and avoid hypoglycemia and hypothermia. If only the hind limbs are affected, they can be hobbled so that the pig can lever itself up using forelimbs and hop around to nurse. Various hobbles, including a figure-eight tape or bandage, have been successful.

Some recommend taping the pelvic limbs so that they are directed cranially on the belly. By using the limbs or pushing against a belly band, the pig potentially develops and strengthens muscles, which can enable it to walk after a few days. Hobbles must be removed within a few days of walking, to avoid ischemic necrosis of the skin and other tissues as the pigs grow.

Pigs with splayleg may require assistance to suckle colostrum and milk for the first few days of life. Some advocate the use of “hot boxes” to nurture these and other ailing pigs, relying on milk replacers as the main source of food once the pig has had colostrum. Because slippery floors exacerbate the condition, temporary use of sanitized mats may help. Any nutritional deficiency or mycotoxin contamination of food should be addressed.

Iron toxicosis in piglets due to injection with iron preparations soon after birth may be associated with muscle fiber fragility, especially if the sow, and therefore the piglet, has a vitamin E or selenium deficiency. Inadequate hygiene or technique when baby pigs are injected with an iron preparation can lead to bruising and septic myositis. This problem can be resolved by adequate training of farrowing-room staff.