The British pig health schemes: integrated systems for large-scale pig abattoir lesion monitoring.

Pig health schemes based on abattoir inspections provide an integrated system to optimise the postmortem detection and the reporting of pathological lesions. In Great Britain, two initiatives have been implemented by the pig industry: Wholesome Pigs Scotland (WPS) and the BPEX Pig Health Scheme (BPHS). These schemes record the presence of a range of pathological lesions detected by means of detailed inspection of the pluck and the skin of the slaughtered pigs. The lesions are those associated with a reduction in performance traits or are indicators of animal welfare problems. This paper aims to provide an overview of the objectives behind the BPHS and their activities, outlining similarities and differences between WPS and BPHS on five main operational topics: the lesions monitored, the administration of the schemes, flow of the information, inspection strategies and the major idiosyncratic characteristics of the schemes. These initiatives inform individual producers and their veterinarians of the occurrence of pathological conditions affecting their pig herds. Additionally, they offer the added value of providing nationwide disease monitoring information and have the potential to be a useful surveillance tool for emerging and enzootic conditions.

Characteristics of commercial pig farms in Great Britain and their use of antimicrobials.

A mail survey of 1889 pig producers in Great Britain with more than 100 sows or more than 1000 pigs was carried out to investigate their use of antimicrobials and other health-related management practices. The response rate was 25.5 per cent. Antimicrobials were most commonly administered in feed. Depending on the production system, between 60 and 75 per cent of the farms had used antimicrobials in their weaner rations and 20 to 62 per cent had used them in their grower rations. Antimicrobial injections had been used on 59 per cent of the farms. The use of antimicrobials in pigs of different age groups was variously associated with the scale of production, membership of a quality assurance scheme, the use of vaccination and whether the farmer thought the farm environment could be improved. Half the respondents (49 per cent) indicated that they used growth promoters in their weaners, but fewer used these in their growers (45 per cent) and finishers (34 per cent). Although 63 per cent of the farmers felt that the continued use of antimicrobials for disease prevention was justified, only 21 per cent felt that their continued use as growth promoters was justified.

Epidemiology of porcine non-specific colitis on Scottish farms.

The objective of this study was to investigate epidemiological risk factors for porcine non-specific colitis (NSC). Forty-seven Scottish pig farms, with and without a clinical history of diarrhoea during the growing period (15-40 kg), were selected. The study included farm visits, clinical inspection of pigs, completion of farm management questionnaires, pathological tests into the cause of the diarrhoea and analysis of the non-starch polysaccharide (NSP) content of feeds. The results from 17 farms designated as NSC and 10 control farms suggest dietary associations with NSC. Farms with NSC fed diets with significantly higher levels of NSPs, especially containing the sugars glucose, arabinose and xylose. Few management factors were identified, although the high prevalence of infectious colitis reduced the power of the study.

Concurrent bovine viral diarrhoea virus and Salmonella typhimurium DT104 infection in a group of pregnant dairy heifers.

Two days after being imported into the United Kingdom one of a group of 30 pregnant dairy heifers showed clinical signs of bovine viral diarrhoea virus (BVDV) infection and subsequently died. Before it died the heifer was BVDV antigen-positive and antibody-negative. The gross post mortem findings were suggestive of mucosal disease but in addition to noncytopathic BVD virus, Salmonella typhimurium DT104 was cultured from tissues and gut contents. The other heifers were screened for S typhimurium by culturing faeces, and serology showed that 13 (45 per cent) of the group seroconverted to BVDV in the three weeks between samplings and the remainder were seropositive, indicating previous exposure. During this period four heifers showed clinical signs of acute BVDV infection but recovered uneventfully. Four animals (14 per cent) were positive for S typhimurium DT104 on faecal culture, and three of these excretors concurrently seroconverted to BVDV. Of the 29 heifers remaining in the group, one aborted in late gestation, 26 bore live calves and two delivered stillborn calves. Pre-colostral blood samples from the calves showed that their dams' pre-existing antibody titres correlated well with in utero fetal protection. In non-immune dams, exposure to BVDV between 69 and 120 days of gestation led to the birth of live persistently viraemic calves. Infection between 120 and 140 days of gestation led to the birth of live calves with evidence of congenital damage to the central nervous system, and infection later than 140 days of gestation led to the birth of live, normal calves with high pre-colostral antibody titres to BVDV. One calf which sucked colostrum was antibody and virus antigen-positive when sampled at 12 hours old but regular blood sampling failed to detect viraemia again until the calf was seven weeks old when it became persistently viraemic.

The use of combined xylazine and lignocaine epidural injection in ewes with vaginal or uterine prolapses.

Two millilitres of solution calculated to contain 0.07 mg/kg xylazine and 0.5 mg/kg lignocaine injected at the sacrococcygeal epidural site provided caudal analgesia within 2 min in 61 sheep. This analgesic protocol eliminated forceful abdominal straining behavior following replacement of vaginal prolapse for at least 24 h in 48 of 52 ewes (92%) and in all 9 ewes with uterine prolapse. Moderate pelvic limb ataxia was observed in 25 sheep (41%) for up to 24 h after epidural injection. Sedation was noted in one ewe but no other systemic effects of xylazine injection, such as excessive salivation or ruminal distension, were observed. No long-term adverse reactions to xylazine injection were noted. The combined epidural injection regimen of xylazine and lignocaine is recommended as an adjunct for pain relief and control of abdominal straining following replacement of vaginal and uterine prolapse in ewes.

Immunological differentiation of pathogenic and non-pathogenic isolates of Entamoeba histolytica.

Entamoeba histolytica can act as a harmless commensal organism in the lumen of the large intestine, or can cause invasive amoebiasis. Some workers have suggested that there are two distinct subspecies of this organism, and that only one of these is associated with invasive disease. Present isoenzyme tests to identify the subspecies take several days to analyse: we report a technique that uses immunofluorescence with monoclonal antibodies, takes two days to perform, and may, therefore, assist in the clinical management of patients infected with this organism.