Veterinary Services

Alimentary tract disorders

An outbreak of scour among recently weaned piglets prompted submission of three four-week-old affected animals. Histopathological examination of intestinal tissues from two of the piglets revealed evidence of viral-type enteropathy in the small intestine and evidence of coccidiosis in the caecum and colon. Rotavirus infection was suspected, although no rotaviral RNA was detected in polyacrylamide gel electrophoresis testing of intestinal contents. In the third pig there was evidence of acute bacterial-type enteritis suggestive of post-weaning colibacillosis. An untyped haemolytic E. coli was isolated from this pig. The herd had a long history of type C rotavirus involvement in post-weaning scour problems but this submission highlighted the often multifactorial nature of piglet scour and the benefit of submitting multiple live cases to achieve a more representative diagnosis.

Clostridial enteritis was suspected as the cause of scour affecting three-day-old piglets in an outdoor herd. Although no clostridia were isolated on bacteriological culture, examination of small intestine from two affected pigs revealed lesions of acute necrotising enteritis with extensive clostridial invasion of the mucosa and submucosal oedema, congestion and haemorrhage. Sows had not received any clostridial or E. coli vaccination.

Six pigs, between six and seven weeks of age, were submitted from a unit reporting 30% mortality in a group of outdoor-reared pigs weaned into an off-site straw court. Similarly reared pigs weaned into strawed accommodation on the main unit were unaffected. Widespread diarrhoea and poor growth were noted within a week of entering the accommodation. Severe typhlocolitis was noted on gross post mortem examination of all pigs with terminal ileitis in some of the cases. Salmonella Goldcoast was isolated from all pigs. Histopathological examination of tissues revealed a complex picture of intestinal disease. In two of the younger pigs there was evidence of small intestinal villous atrophy with submucosal inflammatory cell infiltration consistent with a subacute viral-type enteropathy. Bacterial-type colitis was observed in both pigs, with spirochaetal involvement in one of the pigs suggestive of Brachyspira pilosicoli infection (although no Brachyspira spp. were isolated) and mixed bacterial-type colitis in the other. Lesions suggestive of post-weaning multisystemic wasting syndrome were not observed in these two pigs although lymphoid depletion and histiocytic infiltration characteristic of the disease were noted in four older pigs submitted (in conjunction with mixed bacterial-type colitis). It is thought likely that a combination of rotaviral infection and salmonellosis immediately post-weaning was responsible for the initial problem, with PMWS as a secondary challenge. A second batch of pigs in a neighbouring court suffered similar problems but subsequent batches in different accommodation appeared to be unaffected. Rigorous cleansing, disinfection and resting of the affected accommodation was suggested prior to any further use.

Respiratory tract diseases

The introduction of infected replacement gilts was thought to be responsible for an outbreak of enzootic pneumonia (EP) in a commercial herd. The gilts had been moved into the sow shed directly from the multiplication herd (without quarantine) on which an EP breakdown was subsequently confirmed.

Neurological disorders

Spinal meningioma was diagnosed following post mortem examination of a seven-week-old pig with history of poor hind limb motor control and "knuckling", but otherwise healthy. Other pigs in the litter were clinically normal. No gross abnormalities were detected in the brain, spinal cord or any of the locomotor structures, but histopathological examination revealed a ventral spinal meningioma in the thoraco-lumbar spinal cord. No abnormalities were detected in other neurological and muscle tissues examined.