Veterinary Services

Generalised and systemic conditions

A 12-week-old pig was submitted from a unit with a history of post-weaning multisystemic wasting syndrome (PMWS) reporting increased mortality due to "sudden deaths". Gross post mortem examination revealed enlarged pale kidneys with extensive cortical petechiation. Lesions of porcine dermatitis and nephropathy syndrome (PDNS) were confirmed on histopathological examination. There was marked carcase pallor and haemoperitoneum due to a ruptured liver, likely to have been a terminal event. There was also evidence of myocardial oedema and marked hepatic congestion suggestive of acute right-sided cardiac failure. It is not known whether this case was representative of the mortality problem on the unit.

Alimentary tract disorders

Type C rotaviral RNA was detected by polyacrylamide gel electrophoresis in faeces from scouring ten-day-old pigs from one unit. Rotavirus (again type C) had been confirmed in November 2005 as the cause of poor post-weaning performance and occasional scour in five-week-old pigs in which histopathological lesions of subacute, but ongoing, viral-type enteropathy had been detected. This was the first time for over a year that diarrhoea problems in the farrowing house had been reported.

Swine dysentery was diagnosed in scouring adult pigs on one outdoor breeding unit. Brachyspira hyodysenteriae-specific DNA was detected by polymerase chain reaction (PCR) in colon contents from one sow and one boar and large spirochaetes were observed in the colonic crypts on histopathological examination of tissues from the sow.

Musculo skeletal conditions

Six pigs were examined from a straw-based finishing unit describing acute onset lameness and some "sudden" deaths within three weeks of arrival on the unit. Some of the lame pigs appeared to respond to parenteral amoxycillin therapy but a number of them failed to respond and subsequently died or were euthanased. A number of causes were identified in the pigs submitted, including osteochondritis dissecans (OCD) and infection due to Mycoplasma hyosynoviae in lame pigs euthanased on-farm and Glässer's disease in both "found dead" and euthanased cases. Considerable activity had been noted in the pigs on arrival and it is possible that excessive exercise in these pigs, previously housed in slatted accommodation, had exacerbated any lameness due to OCD. Mixing of a large number of pigs (albeit from the same source breeding unit) may have increased transmission of Mycoplasma hyosynoviae and Haemophilus parasuis among the group, the latter infection perhaps explaining the partial response to antibiotic therapy and at least some of the reported mortality.

Reproductive disorders

Abortion due to Staphylococcus hyicus was diagnosed in a fourth parity outdoor sow, which had produced stillborn piglets, approximately three weeks before due date. The sow had appeared slightly lethargic and inappetant but without any specific clinical signs and no other cases were reported on the outdoor breeding unit concerned. No significant gross fetal lesions were observed but S. hyicus was isolated from the stomach contents of both piglets examined and from the placenta submitted. A sporadic case of uterine infection with S. hyicus was suspected.