No abstract

The aim of this retrospective study was to reveal the causes of bovine abortions, stillbirths and neonatal deaths in Finland. All cases submitted for necropsy to laboratories of the Finnish Food Safety Authority Evira between 1999 and 2006 were included. A total of 434 cases were received, of which the majority (336) were obtained as routine laboratory diagnostic service and additional 98 cases from two research projects. The production type was available in 242 cases, of which 55% were from dairy farms and 45% beef cow-calf farms. A total of 271 entire fetuses, 147 stillborn or neonatal calves dead within the first 24 hours and sixteen tissue samples were obtained. Placental tissue was available in 116 cases (26%).A full necropsy was performed to fetuses and calves including sample collection for histopathology, bacteriology and virology as appropriate. Conventional bacteriological methods were used for culturing aerobic, anaerobic, and microaerophilic bacteria, fungi, salmonella, campylobacteria, and staining for brucella. Since 2004 detection of mycoplasma was performed (total n = 146). BVD (n = 188) and IBR (n = 188) viruses were isolated in cell culture and serology was used for BVD, IBR and bovine parvovirus for 48, 50, and 93 samples, respectively. (1) were found occasionally. In neonatal calves Bacillus licheniformis (7/140, 5%)) was the most common bacterial isolation, followed by Escherichia coli (3), Staphylococcus sp. (3) and Arcanobacterium pyogenes (1), Streptococcus sp. (1) and Mannheimia varigena (1). Neospora caninum was diagnosed from three cases showing encephalitis or myositis.None of the samples were positive for BVD or IBR viruses, neither their antibodies. Parvovirus antibodies were common (58%, 56/93), however no pathological lesions were associated with parvovirus seropositivity. Thus the significance of this finding remains questionable.

Two hundred and forty piglets were used in a 2 x 6 factorial experiment to study the effects of weaning age (26 or 36 d) and four formic acid-based feed additives on the performance of pigs from weaning to slaughter. Either formic acid (F) or a mixture of formic acid, propionic acid, and potassium sorbate (FPS) or a mixture of formic acid, propionic acid, and sodium benzoate (FPB) or formic acid in a diatomaceous earth carrier (FD) were added to the diets of weaned piglets (from weaning to 60 d of age) and growing (18-46 kg) and finishing pigs (46-107 kg) to provide 8, 6, and 6 g acid per kg feed, respectively. The negative control treatment's (C) diets contained no growth promoters, whereas the positive control treatment's weaner and grower diets were supplemented with 40 mg/kg of avilamycin (A). The piglets weaned at the age of 26 and 36 d weighed 7.6 and 10.7 kg at weaning (p < 0.001), and 18.5 and 17.9 kg at the age of 60 d (p > 0.05), respectively. There was a weaning age x feed additive interaction in the weight gain of piglets after weaning (p < 0.05). The weight gain of piglets weaned on day 26 was enhanced by A, FPS, and FD (p < 0.05), and that of piglets weaned on day 36 by A and FPB (p < 0.05). The feed conversion ratio was not affected by weaning ages but was decreased in groups A, F, FBS, and FPB (p < 0.05). The severity of post-weaning diarrhoea was less in groups A, F, FPS, and FD than in C (p < 0.05). In piglets weaned on day 26, faecal water content and the total Escherichia coli count were highest 9 d after weaning. The total E. coli count was reduced only by FD (p < 0.05). Increased faecal water content was characterized by increased faecal Na+ and decreased K+ concentrations. Weaning age did not influence performance or carcass quality in the growing-finishing pigs. Feed additives did not affect weight gain in the growing pigs, but FPS and FPB enhanced weight gain during finishing period and total fattening (p < 0.05). In summary, the pigs' growth performance from weaning to slaughter was not affected by weaning age but it was enhanced by mixtures of formic and propionic acids with small amounts of sorbate or benzoate.

There are no approved standards for antimicrobial susceptibility testing of the fastidious spirochete Brachyspira hyodysenteriae. An interlaboratory study was performed to establish MIC quality control ranges for six antimicrobial agents for the type strain of B. hyodysenteriae using broth dilution. The results showed that B. hyodysenteriae B78T ATCC 27164T is a suitable quality control strain. This is a first step toward standardization of methods regarding this anaerobe.

Faeces samples were taken three times at two-week intervals, from the farrowing units of four herds of known Brachyspira (formerly Serpulina) status and one of unknown Brachyspira status. Brachyspira hyodysenteriae, Brachyspira pilosicoli, Brachyspira intermedia and Brachyspira group III were isolated from the faecal samples from the weaners in the herds using either a maximum of 50 ppm of olaquindox or no feed additives. The detection rates were relatively consistent. However, B hyodysenteriae was not detected at one sampling in a known positive herd. The prevalence of Brachyspira species was also studied in feeder pigs originating from LSO 2000 health class farrowing units, comparable with specific pathogen-free herds. These farms were free from swine dysentery, sarcoptic mange, swine enzootic pneumonia and progressive atrophic rhinitis. Fifty of 428 herds were sampled once. B hyodysenteriae was not isolated from any of them, but B intermedia, B pilosicoli and Brachyspira group III were isolated from five, 14 and 37 of the herds, respectively. The detection of Brachyspira species did not relate to the prevalence of diarrhoea in the herds, as judged by the farmers. The herds using carbadox (40 to 50 ppm) had a lower prevalence of Brachyspira species than those using olaquindox (40 to 50 ppm).