Veterinary Services

Generalised and systemic conditions

Porcine stress syndrome was diagnosed in a stud boar that had been found dead in its pen subsequent to an unsuccessful attempt to collect semen. Pale soft exudative muscle was seen in several muscle groups, most marked in the hamstring, triceps and psoas muscles. Histopathological examination of tissue revealed acute myofibre degeneration. No other evidence of intercurrent disease was detected. The finding of such lesions in a breeding line reported to be free of the Haln (Hal 1843) mutation is unusual.

Alimentary tract disorders

An investigation was undertaken into the cause of a 10% mortality rate in finishers between 40 and 100kg bodyweight on a whey-feeding unit. Post mortem examinations showed gross changes consistent with whey bloat in all cases. The fault was thought to lie in the high proportion of the diet being fed as whey (40% of dry matter equivalent). Nutrition company advice suggested reducing the whey component to 20% of the diet and increase the available concentrate feeding accordingly. The outcome of these changes is awaited.

Four ten-week-old pigs were submitted to investigate a problem of black scour, dysentery, wasting and increased mortality. Post mortem examination revealed colitis of varying severity with the worst affected cases showing large areas of mucosal necrosis. Brachyspira hyodysenteriae-specific DNA was detected by polymerase chain reaction (PCR) in all four pigs, confirming the diagnosis of swine dysentery.

Respiratory tract diseases

An enzootic pneumonia (EP) breakdown was suspected on one "high health" unit reporting an outbreak of coughing (of two months duration) in weaned pigs of all ages. An increased average lung score had also been detected during routine abattoir monitoring with around 70% of slaughter pigs showing EP-like lung lesions. Gross examination of two sacrificed seven-week-old pigs revealed generalised pale anteroventral pulmonary consolidation. Extensive lesions of exudative bronchointerstitial pneumonia with pronounced peribronchiolar lymphocytic "cuffing" reaction were observed on histopathological examination of affected lung. Although no Mycoplasma culture or PCR testing was performed, the clinical picture and the histopathological findings were considered consistent with EP due to Mycoplasma hyopneumoniae. The source of the breakdown is not known and although the unit had taken in replacement gilts (without quarantine) from a multiplication herd where an EP breakdown was subsequently confirmed, the coughing outbreak appeared to predate the introduction of these pigs.