Purification and quantitative measurement of bovine serum amyloid-A

Bovine serum amyloid-A (b-SAA) was purified from a pool of acute phase serum using hydrophobic interaction chromatography and gel filtration. Serum was applied at a low salt concentration to a phenyl-sepharose column and SAA was eluted with a gradient of 0 to 6 M guanidine-HCI. Fractions containing SAA were pooled, concentrated and further purified by gel filtration on Superose-12. The concentration of SAA in bovine serum was quantified by an indirect ELISA using rabbit anti-human SAA and horseradish peroxidase conjugated donkey anti-rabbit IgG. Dilutions of an acute phase bovine serum sample were used as working standards. The SAA concentration of this standard was determined by comparison with purified b-SAA on SDS-polyacrylamide gel electrophoresis followed by densitometry at 590 nm. The assay detection limit was 3 μg ml⁻¹; the intra-assay coefficient of variation was 4 per cent and interassay coefficients of variation were 5·5 per cent and 7·2 per cent at 66 and 178 μg ml⁻¹ SAA, respectively. In calves experimentally infected with Pasteurella haemolytica type A1 the ELISA was able to detect a 10-fold increase of SAA within 24 hours of inoculation.     

Kunjin flaviviral encephalomyelitis in an Arabian gelding in New South Wales, Australia

Flaviviruses, including Kunjin virus, are arboviruses that cause encephalomyelitis in humans and horses. This case report describes an Arabian gelding exhibiting neurological signs of flavivirus encephalomyelitis, the diagnostic investigation and confirmation of an unreported case of Kunjin virus equine encephalomyelitis in Australia.     

Nutritive value of forage species grown in the warm temperate climate of Australia for dairy cows: Grasses and legumes

The objective of this study was to quantify the differences in the nutritive value over 4 seasons, of 7 C₃ temperate grasses, 2 C₄ tropical grasses and 11 clover species used as forages for dairy cows. The nutritive value was assessed in terms of nutrient content and the availability of effective rumen degradable protein, rumen by pass protein, metabolisable protein (MP) and fermentable metabolisable energy.

All species were grown in plots as monocultures under conditions of non limiting nutrients and moisture and harvested by mechanical means. All species had a high crude protein content and this resulted in a high effective rumen degradable protein: fermentable metabolisable energy ratio varying from 15, for cowpeas (Vigna unguiculata) to 29 for birdsfoot clover (Lotus corniculatus), and all were above the ratio of 11 required for optimal microbial protein synthesis in the rumen of dairy cows. The calculated availability of MP varied from 105 g/kg dry matter (DM) for cowpeas to 173 g/kg DM for berseem clover (Trifolium alexandrinum) indicating that all forages would be able to meet the requirements of dairy cows producing up to 30 L/milk/day, provided they were able to consume over 19 kg DM of forage/cow/day.

Grasses had much higher hemicellulose (neutral detergent fibre minus acid detergent fibre) content than legumes. Kikuyu (Pennisetum clandestinum), a C₄ grass, had a higher proportion of hemicellulose content than the C₃ temperate grasses. Perennial ryegrass (Lolium perenne) and kikuyu had a similar metabolisable energy (ME) density (9.9 MJ/kg DM) in summer. The mean ME density of perennial ryegrass, prairie grass (Bromus wildinowii) and short rotation ryegrass (Lolium multiflorum) winter was similar at 10.6 MJ/kg DM and slightly higher than cocksfoot (Dactylus glomeratus), phalaris (Phalaris tuberosa) and fescue (Fescue arundunicea) which had a mean ME density of 10 MJ/kg DM.

All forages grown were able to satisfy MP and ME requirements of dairy cows producing up to 30 L milk/cow/day, provided they were able to consume sufficient forage to achieve this level of production.     

Effects of collecting serial tracheal aspirate and bronchoalveolar lavage samples on the cytological findings of subsequent fluid samples in healthy Standardbred horses

Objective To evaluate the effect of collecting serial tracheal aspirate (TA) and bronchoalveolar lavage (BAL) samples on the cytological findings of subsequent fluid samples obtained from horses without clinical signs of respiratory disease. Study design Experimental. Study population Six healthy Standardbred horses. Methods Endoscopically‐guided TA samples, and BAL samples collected using the blind field technique were obtained from the six horses on days 1, 2, 3, 4, 5, 12, and 17. On day 17, horses were sampled three times: at baseline and at 2.5 h and 4 h apart. The differential cytology of the fluid samples collected at each time point was expressed as percentages and compared statistically. Results There was a significant increase in neutrophil percentage in the TA samples taken at day 17 (at 2.5 h but not at 4 h apart). There was no significant change in the neutrophil percentages in the TA samples when repeated samples were taken ≥24 h apart. There was no significant change in the neutrophil percentages in the BAL fluid at any collection point. There were inconsistent changes in the percentages of lymphocytes and macrophages in the BAL fluid over time, but these remained within normal reference ranges and were considered clinically insignificant. Conclusions Serial TA and BAL samples can be taken at 24 h intervals without affecting the cytological findings of subsequent fluid samples collected using the techniques described.     

Acute phase proteins in cattle: discrimination between acute and chronic inflammation.

Acute phase proteins such as serum amyloid A, haptoglobin, and alpha 1-acid glycoprotein have been identified as markers of inflammation in cattle because they are produced by the liver in response to pro-inflammatory cytokines. This study was designed to assess whether they could be used to discriminate between acute and chronic inflammation. Their concentrations were measured in serum samples from 81 cattle in which inflammation was classified by thorough clinical examination, supported by postmortem findings, as being acute in severity in 31 and chronic in 50. The classical haematological markers of inflammation were also determined in blood from the animals. Serum amyloid A had a maximum (100 per cent) clinical sensitivity in discriminating between the acute and chronic cases, and haptoglobin had the highest clinical specificity of 76 per cent; counts of neutrophils and band neutrophils had sensitivities of 71 per cent and 42 per cent and specificities of 30 per cent and 72 per cent, respectively. It was concluded that serum amyloid A and haptoglobin may be used to discriminate between acute and chronic inflammatory conditions.     

Studies on Cellulitis and Other Disease Syndromes Caused by Escherichia coli in Broilers in Sri Lanka

Cellulitis caused by Escherichia coli in broilers results in substantial losses to the broiler industry in North America and Europe due to condemnations at slaughter. The objective of this study was to identify cellulitis in broilers in Sri Lanka and to characterize the E. coli from cellulitis and other colibacillosis lesions. Twenty-four farms from the low- and mid-country were selected and bacterial isolations were obtained from 241 birds. Two hundred and ninety-one gross lesions were observed in these 241 birds and 162 E. coli isolates were obtained. Cellulitis was observed in 21% of the birds. Twenty-one per cent of the birds had multiple lesions due to E. coli. The frequency of detection of other disease syndromes was 162 (67%) birds with pericarditis, 26 (11%) airsacculitis, 24 (10%) hepatitis, 12 (5%) perihepatitis, and 16 (7%) polyserositis (a combination of pericarditis, perihepatitis and airsacculitis). Serogroups O78, O2, O85 and O88 were distributed among the 32% of typable E. coli and 81% of isolates were assigned to three biotypes. Forty-four per cent of the E. coli isolates produced aerobactin and 88% demonstrated resistance to the bactericidal effect of normal chicken serum. The majority of the E. coli isolates were resistant to the antibiotics commonly used in poultry. All the E. coli isolates were non-haemolytic and 25% of the isolates produced K1 capsule. This study demonstrated the presence of cellulitis in Sri Lanka and this report describes some of the phenotypic characteristics of the E. coli isolates.     

化药防治羊硬蜱病试验

将1150只感染有草原革蜱和森林革蜱的绵羊分为3个组,分别为驱蜱项圈组（400只）、灭蜱灵组（550只）和对照组（200只）。项圈组在治疗后0、7、15、28、45、60、75、95天,羊只平均染蜱数分别为10.3、0.9、0.7、0.3、0.4、0.5、0.5、0.1只;而对照组分别为10.2、9.2、13.6、10、9.2、6.4、8.8、4.2只。灭蜱灵组在治疗后0、18、33、48、68天,羊只平均染蜱数分别为9.8、0.5、0.7、0.5、0.1只,而对照组分别为10、9.2、6.4、8.8、4.2只,表明两个防治组保护效果均较好。