Veterinary Services

An umbilical hernia, fibrinous peritonitis and intussusceptions were diagnosed in a nine-week-old boar. There were four deaths due to ruptures over a four day period and a further three live affected boars were failing to thrive. Only boars were affected.  There was an eight to ten cm. diameter hernia at the umbilicus, with skin ulceration on the ventral aspect of the hernia. The ventral wall of the hernia was about three to four cms thick due to oedema. The hernia contained fibrinous material but the intestine had not herniated. The abdomen contained a large amount of fibrin and there was an adhesive peritonitis present, especially involving the intestines. There was also an eight cm. intussusception and a large organising blood clot, about 25 cm. in length, in the adjacent intestinal lumen. SAC C VS advised that the breeding records should be examined to identify if a particular boar was the sire of all of the cases.

Malignant lymphoma was diagnosed in an 18-week-old finishing pig that died suddenly. There was massive enlargement of lymph nodes, especially the mesenteric nodes which were up to four cm. in diameter. On histopathology the lymph nodes were heavily infiltrated by immature lymphocytes leaving little evidence of lymph node structure. Many mitotic figures were evident in these lymphocytes. Immature lymphocytes had also infiltrated the renal cortex, occupying the interstitial tissue and forming irregular masses.

Alimentary tract disorders

Two six-week-old boars died following the onset of acute scour and dehydration in a group that were on a feed change. Both pigs had flocculent, grey, very watery colonic contents. Profuse growths of Salmonella Typhimurium phage type 120 were isolated in direct and in enrichment cultures from the small and large intestinal contents of both pigs. In a different herd, ill thrift and diarrhoea with ten per cent morbidity was reported to be affecting two pens of seven-week-old pigs. Four deaths had occurred. Salmonella Typhimurium phage type 120 and K88 E. coli were isolated in cultures. On histopathology there was a moderate, diffuse lympho-plasmacytic typhlocolitis. SAC C VS considered the non-specific histopathological changes could have arisen in association with chronic low-grade salmonellosis or could have been diet-related, with opportunistic salmonella involvement.

Brachyspira hyodysenteriae DNA was detected by PCR in faeces from 15-week-old pigs that were showing signs of scour and weight loss. They had been treated for swine dysentery but the problem was continuing. Swine dysentery was diagnosed on another two units where the disease was known to exist but had been well-controlled medically.  Oesophagostomum dentatum eggs were detected in significant numbers (150 to 750 eggs per gram) in four faecal samples from gilts with loose faeces from the same unit.  These samples also contained low numbers of coccidial oocysts (300 to 500 oocysts per gram).  Four samples from another unit with a similar history had coccidial oocyst counts of up to 25,200 o.p.g.

Respiratory tract disorders

An outbreak of respiratory disease occurred in a unit which was considered to be free of enzootic pneumonia. Coughing began in the breeding herd but spread to the weaners. Two affected sows were euthanased and submitted for postmortem examination. In one there was deep purple congestion of the lungs and severe generalised oedema. The lungs failed to collapse and there was a large volume of froth in the trachea. The other had generalised pulmonary congestion and oedema and deep pink consolidation of the apical, middle and accessory lobes of the lungs and margins of the diaphragmatic lobes. The diaphragmatic lung lobes were mottled and the lungs were overinflated. Histopathology revealed similar changes in both, comprising widespread acute interstitial pneumonia, necrotising bronchiolitis, diffuse pulmonary oedema and fibrin exudation. The bronchiolar epithelium was necrotic with an intense inflammatory cell reaction. There was also evidence of acute lymphadenitis in the mediastinal lymph node. Fibrinous thromboemboli were present in some of the pulmonary capillaries of the second sow. Although the changes suggested an acute viral-type pneumonia, possibly swine influenza, no influenza A RNA was detected by PCR. However, Mycoplasma hyopneumoniae DNA was detected by PCR in the lung samples.  This was the start of a major enzootic pneumonia breakdown in the herd. Subsequently all six sows blood sampled for Mycoplasma hyopneumoniae serology were antibody positive in the ELISA test.