Alimentary tract diseases

Salmonellosis

The carcases of two growing pigs aged six weeks were submitted to Winchester as part of an investigation into increased mortality within a group of 900 growers. Necropsy revealed an extensive fibrino-necrotic colitis and typhlitis and a multi-resistant Group B Salmonella 4,5,12;i;-, a monophasic variant of Salmonella Typhimurium, was isolated.

Bury also diagnosed Salmonellosis as the cause of necrotising colitis in seven-week-old housed pigs. The salmonella isolated was S. Typhimurium phage type U288 and showed multi-drug resistance (resistant to tetracycline, ampicillin, sulphamethoxazole/trimethoprim, chloramphenicol, streptomycin and sulphonamide compounds) as commonly seen in S. Typhimurium isolates from pigs. In both cases appropriate advice was given on disease control and potential zoonotic risk.

Respiratory Diseases

Actinobacillus pleuropneumoniae

Two 17-week-old pigs were submitted to Thirsk for investigation into sudden death in finishing pigs. The unit was experiencing four per cent post-weaning mortality, almost all of this in the month prior to slaughter. Post-mortem examination revealed generalised fibrinous peritonitis and pericarditis with a necrotising tracheitis in one pig. The lungs of both animals demonstrated consolidation affecting approximately 50 per cent of lung tissue. Actinobacillus pleuropneumoniae and Pasteurella multocida were isolated from lung tissue; Bury also identified Actinobacillus pleuropneumoniae as the cause of thirty-five post weaning deaths in a batch of 400, ten week old growers. Pigs were seen coughing and dyspnoeic prior to death.

Other diseases

Detachment of the Ischial Tuberosity

Bury investigated a problem of increased culling of homebred replacement gilts at various stages from service to farrowing. The gilts showed malaise and lameness unresponsive to antimicrobial or anti-inflammatory treatment. Necropsy of one gilt which had farrowed, revealed detachment of the left ischial tuberosity of the pelvis associated with a large abscess at the site of separation. Detachment of the ischial tuberosity in sows was described by Done et al (1979, Veterinary Record Vol. 105 pp 520 - 523). Another gilt submitted had lesions consistent with osteochondrosis dissecans in both shoulder joints with bony changes in the joints indicating secondary osteoarthritis. In one of the shoulder joints, a cartilage flap had recently separated from the articular cartilage leaving exposed bone which was likely to have been painful and to have caused malaise in the gilt. Factors contributing to the development of osteochondrosis on the farm are being examined.

Neurological Diseases

RVC diagnosed Congenital Type A2 tremors in a litter of piglets that were all euthanased soon after birth. The litter was from a different farm to a case previously investigated in June. However, the gilt in this new outbreak originated from the previous farm and had temporarily returned to it for service. Piglets with A2 tremors have a deficiency of spinal cord myelin. The cause of A2 tremors is thought to be in utero viral insult of unknown identity although PCVII has been implicated in some cases.

Further Reading

-

Find out more information on the diseases mentioned by clicking here.