Veterinary Services

Severe skin lesions were reported in two litters of seven-day-old piglets. 40 to 50 percent of each litter was affected and two piglets died. There were multiple irregular areas of hyperaemic skin, in many places becoming confluent, affecting the whole body and limbs (figure 3 - see top right-hand side). Yellow exudate was present and, in some areas, thickening of the epidermis and dermis but minimal scab formation. Staphylococcus chromogenes was isolated from the skin lesions. Histopathology demonstrated widespread acute necrotising epidermopathy and folliculopathy associated with invasive bacterial (coccal) infection. In a third piglet there were more chronic lesions. Congestion, haemorrhage, oedema and acute inflammation more typical of exudative epidermitis were present. The SAC considered the findings consistent with severe necrotising staphylococcal epidermal infection with fibrin exudation and sequelae.

Two of three four-week-old piglets submitted for postmortem examination had swollen joints while the third was inco-ordinated and reluctant to move.  The latter pig had yellow necrotic debris on the gums where the teeth were clipped. At necropsy there were multiple irregular pale areas on the liver surface. The left elbow and both stifle joints contained excess cloudy synovial fluid. Streptococcus suis serotype 1/14 was isolated from the liver and cerebrospinal fluid and Streptococcus dysgalactiae subsp equisimilis from the gums. The latter organism was also isolated from both hock joints of one pig with swollen joints.

The presence of mycotoxins in the feed was associated with ill thrift affected growing pigs on a unit from seven weeks of age. The mortality rate was 20 percent. Moderate growths of Actinobacillus pleuropneumoniae were isolated from the lungs of three of six ten-week-old pigs submitted for postmortem examination. One of these had small enzootic pneumonia-like consolidated areas in the cranial lung lobes and another had adhesive pleurisy. All three had evidence of viral-type pneumonia on histopathology. One pig had mild greasy pig disease. Another had excess peritoneal fluid and pleurisy. Haemophilus parasuis was isolated in profuse growth from the lung, confirming that this was a case of Glasser’s disease. On histopathology the pigs showed consistent changes in the lymphoid tissues. The spleens had very prolific extramedullary haemopoiesis with numerous megakaryocytes. There were also numerous precursor cells, mainly of the erythrocyte series. The lymph nodes had numerous precursors of mainly the myelocyte series. The SAC considered these findings indicative of severe bone marrow suppression and suspected a toxic cause.  Subsequent testing of bile samples from cohort pigs from the unit showed high mycotoxin levels.

An outdoor, organic herd experienced three sudden deaths in a group of 16 five-month-old Gloucester old spot pigs.  The field was exposed with poor shelter and the pigs were fed whey, cheese, bread, oats and bran.  At postmortem examination an increased volume of pericardial fluid was seen and the right side of the heart appeared slightly dilated.  Histopathology was onsistent with hepatosis dietetica and cardiac failure.

Hepatosis dietetica was also diagnosed in a nine-month-old pot-bellied boar fed a diet of barley, cabbage and bananas. The liver showed a combination of lesions from acute to chronic on histopathology. There was widespread acute hepatocellular degeneration affecting periacinar and midzonal regions. In addition, there was widespread distortion of lobules, disorganised structure, regeneration of hepatocytes in portal areas and areas of fibrosis and inflammation. The acute hepatic lesions were consistent with a diagnosis of hepatosis dietetica. The chronic features suggested previous sublethal episodes resulting in distortion and disorganisation.

Alimentary conditions

Two five-month-old pigs were submitted for postmortem examination to investigate the cause of sudden deaths shortly after movement. A gilt had serosal corrugation and thickening of the small intestine, with blood clots attached to the mucosa. The large intestine had patchy dark areas associated with dried blood clots adherent to the mucosa. On histopathology there was a proliferative and necrotising enteropathy suggestive of Lawsonia intracellularis infection. The small intestines contents were liquid and bloody. On histopathology there was severe intestinal necrosis and haemorrhage. Proliferative haemorrhagic enteropathy was diagnosed by histopathology and demonstration of intracellular bacteria typical of L. Intracellularis.

Locomotor conditions

Three six month old pigs were submitted from a herd with a lameness problem.  Affected joints contained watery, blood stained joint fluid and the synovial membrane was inflamed.  M. hyosynoviae was isolated in all cases.