Trichostrongylid infections in sheep after rainfall during summer in southern Australia

OBJECTIVE: To relate trichostrongylid infections acquired by sheep during summer to prevailing weather conditions. PROCEDURE: Groups of worm-free 'tracer' sheep were put onto pastures, previously contaminated with trichostrongylid eggs, for successive periods of 2 weeks from December to March. After grazing the sheep were housed for 6 weeks. Weekly worm egg counts and worm counts were used to estimate the numbers of worms acquired and related to weather conditions during the grazing period. RESULTS: No worm eggs were detected in the faeces of sheep that grazed at the end of January when only 7 mm of rainfall was recorded. At other times rainfall between 12 and 24 mm occurred and strongyle egg counts were generally either < 50 or > 150 eggs per g (epg). Mean counts of 1,100 Ostertagia and Trichostrongylus adults gave rise to mean counts of about 350 epg whereas about 6,000 Nematodirus spp were associated with mean egg counts of about 200 Nematodirus spp epg. CONCLUSIONS: Rainfall events during summer determine the numbers of trichostrongylid larvae acquired by sheep in summer but further studies are necessary before the implications for strategic control programs in southern Australia can be fully assessed.     

Linkage analysis using direct and indirect counting and relative efficiencies for codominant and dominant loci

A method based on direct and indirect counting is developed for rapid and accurate linkage analysis for codominant and dominant loci. Methods for estimating gender-specific recombination frequencies are available for cases where at least one of the two loci is multiallelic and for biallelic loci with mixed parental linkage phases where at least one locus is codominant. Most of the estimates of gender-average and gender-specific recombination frequencies required iterative solutions. The new method makes use of the full data set, yields exact estimates of the recombination frequencies when the observed and expected genotypic frequencies are equal, and are computationally efficient. Relative efficiency of various data types is affected by the inheritance mode and by parental linkage phases of biallelic loci, but unaffected by the locus polymorphism when using the full data set for linkage analysis. The ability to determine parental linkage phases is affected by the locus polymorphism as well as inheritance mode. Intercross (or F-2 design) is more efficient for mapping codominant loci, whereas backcross is more efficient if dominance is involved. Mixed parental linkage phases of biallelic loci are less efficient than coupling or repulsion linkage phases. Ignoring noninformative offspring results in biased estimates of recombination frequency for biallelic loci only and reduced LOD scores for all cases.     

Effects of feeding a blend of grains naturally contaminated with Fusarium mycotoxins on swine performance,brain regional neurochemistry,and serum chemistry and the efficacy of a polymeric glucomannan mycotoxin adsorbent

The co-occurrence of Fusarium mycotoxins in contaminated swine diets has been shown to result in synergistic toxicity beyond that observed for individual toxins. An experiment was conducted, therefore, to investigate the effects of feeding a blend of grains naturally contaminated with Fusarium mycotoxins on growth, brain regional neurochemistry, serum immunoglobulin (Ig) concentrations, serum chemistry, hematology, and organ weights of starter pigs. Three levels of glucomannan polymer (GM polymer, extract of yeast cell wall, Alltech Inc.) were also tested for its efficacy to overcome Fusarium mycotoxicoses. A total of 175 starter pigs (initial weight of 10 +/- 1.1 kg) were fed five diets (seven pens of five pigs per diet) for 21 d. Diets included (1) control, (2) blend of contaminated grains, (3) contaminated grains + 0.05% GM polymer (4) contaminated grains + 0.10% GM polymer and (5) contaminated grains + 0.20% GM polymer. Diets containing contaminated grains averaged 5.5 ppm deoxynivalenol, 0.5 ppm 15-acetyldeoxynivalenol, 26.8 ppm fuuric acid, and 0.4 ppm zearalenone. Feed intake and weight gain of all pigs fed contaminated grains was significantly reduced compared to controls throughout the experiment. The weights of liver and kidney, expressed as a percentage of body weight, were lower in pigs fed the contaminated diet than in those fed the control diet. The feeding of contaminated grains significantly reduced concentrations of dopamine in the hypothalamus and pons and concentrations of dihydroxyphenylacetic acid and norepinephrine in the pons. The ratios of 5-hydroxyindoleacetic acid to serotonin, however, were elevated in the hypothalamus and pons. The feeding of contaminated grains increased serum IgM and IgA concentrations, while serum IgG concentrations were not altered. The supplementation of GM polymer prevented some of the mycotoxin-induced alterations in brain neurotransmitter and serum Ig concentrations. In summary, the feeding of grains naturally contaminated with Fusarium mycotoxins reduced growth, altered brain neurochemistry, increased serum Ig concentrations, and decreased organ weights in starter pigs. Some of the Fusarium mycotoxin-induced changes in neurochemistry and serum Ig concentrations can be prevented by the feeding of yeast cell wall polymer at appropriate concentrations, although this was not reflected in increased growth rate under these experimental conditions.     

Effect of high-oil corn or added corn oil on ruminal biohydrogenation of fatty acids and conjugated linoleic acid formation in beef steers fed finishing diets

Three Angus steers (410 kg) cannulated in the proximal duodenum were used in a replicated 3 x 3 Latin square to evaluate the effects of dietary lipid level and oil source on ruminal biohydrogenation and conjugated linoleic acid (CLA) outflow. Dietary treatments included: 1) typical corn (TC; 79.2% typical corn), 2) high-oil corn (HOC; 79.2% high-oil corn), and 3) the TC diet with corn oil added to supply an amount of lipid equal to the HOC diet (OIL; 76.9% TC + 2.4% corn oil). Duodenal samples were collected for 4 d following 10-d diet adaptation periods. Data were analyzed with animal, square, period, and treatment in the model and planned, nonorthogonal contrasts were used to test the effects of dietary lipid content (TC vs HOC and OIL) and oil source (HOC vs OIL) on ruminal biohydrogenation. Intake and duodenal flow of total long-chain fatty acids were increased (P < 0.05) by over 63% for diets containing more lipid regardless of oil source. Apparent ruminal dry matter and long chain fatty acid digestibilities were not altered (P > 0.05) by dietary lipid level or oil source. Ruminal biohydrogenation of total and individual 18-carbon unsaturated fatty acids was greater (P < 0.05) for diets with higher lipid content. Biohydrogenation of oleic acid was greater (P < 0.05) for HOC than OIL, but biohydrogenation of linoleic acid was lower (P < 0.05) for HOC than OIL. Duodenal flows of palmitic, stearic, oleic, linoleic, and arachidic acids were more than 30% greater (P < 0.05) for diets containing more lipid. Flow of all trans-octadecenoic acids was greater (P < 0.05) for diets containing more lipid. Corn oil addition increased (P < 0.05) the flow of trans-10 octadecenoic acid and the trans-10, cis-12 isomer of CLA by threefold compared to feeding high-oil corn. Feeding high-oil corn or adding corn oil to typical corn rations increased intake, biohydrogenation, and duodenal flow of unsaturated long-chain fatty acids. Compared with high-oil corn diets, addition of corn oil increased duodenal flow of trans-10, trans-12 and cis-12 isomers of octadecenoic acid and the trans-10, cis-12 isomer of CLA. The amount of cis-9, trans-11 isomer of conjugated linoleic acid flowing to the duodenum was less than 260 mg/d, a value over 20 times lower than flow of trans-11 vaccenic acid indicating the importance of tissue desaturation for enhanced conjugated linoleic acid content of beef.     

Weaning,yearling, and preharvest ultrasound measures of fat and muscle area in steers,bulls, and heifers

Longissimus muscle area and fat thickness were measured following weaning, at yearling, and prior to harvest using real-time ultrasound, and corresponding carcass measurements were recorded 3 to 7 d following the preharvest scan in composite steers (n = 116, 447 +/- 19 d), bulls (n = 224, 521 +/- 11 d), and heifers (n = 257,532 +/- 12 d). Although fat deposition was limited in bulls and heifers from weaning to yearling, coefficients of variation ranged from 8.46 to 13.46% for muscle area, and from 27.55 to 38.95% for fat thickness, indicating that significant phenotypic variance exists across genders. Residual correlations, adjusted for the effects of year of birth, gender, and age at measurement, were high and ranged from 0.79 to 0.87 among ultrasound and carcass measures of muscle area. Residual correlations among ultrasound and carcass measures of fat thickness were also high, ranging from 0.64 to 0.86. Weaning and/or yearling ultrasound muscle area yielded similarly accurate predictions of carcass muscle area. Yearling ultrasound fat thickness accounted for 13% more of the observed variance in carcass fat thickness than the weaning ultrasound measure in single-trait prediction models. When both weaning and yearling ultrasound measures were used to predict carcass fat thickness, partial R2 values were 0.15 and 0.61 for weaning and yearling ultrasound fat thickness, respectively. The difference between predicted and carcass measures with respect to muscle area (fat thickness) was less than 6.45 cm2 (2.5 mm) for 80.2 to 88.9% (90.3 to 95%) of animals. Preharvest ultrasound measures yielded standard errors of prediction of less than 4.95 cm2 for muscle area and 1.51 mm or less for fat thickness. These results indicate that ultrasound measures taken between weaning and yearling provide accurate predictors of corresponding carcass traits in steers, bulls, and heifers.     

Oestrogen-induced bone marrow aplasia in a dog with a Sertoli cell tumour

A 10-year-old male Drahthaar dog with unilateral cryptorchidism was examined because of feminisation and myelotoxicity. Radiography and ultrasonography revealed an abdominal mass which was surgically removed. The mass was identified as a Sertoli cell tumour on histological examination. Findings on bone marrow examination were compatible with aplasia due to the oestrogens secreted by the tumoral cells. Treatment with fluids, antibiotics, whole blood transfusions, corticosteroids and lithium carbonate was unsuccessful. Survival time was 22 days after surgery.     

New molecular biology detection methods for tick-borne infectious agents

Tick-borne zoonotic pathogens are well known in many areas all over the world. Among the tick-borne transmitted diseases in Switzerland, Lyme disease caused by Borrelia burgdorferi, ehrlichiosis caused by various species of Ehrlichia and tick-borne encephalitis caused by the tick-borne encephalitis virus (TBEV) are the most important zoonotic diseases. Early diagnosis and treatment is necessary to prevent fatal infections and chronic damage to various tissues. Due to the variety of uncharacteristic clinical signs, tick-borne diseases are not easily recognized. Diagnosis is based on clinical findings, a record of tick exposure, and direct or indirect detection of the pathogen. Here we discuss briefly the most important tick-borne infections and their diagnosis with emphasis on a new molecular diagnostic tool--the real-time TaqMan PCR--and its importance for the diagnosis of tick-borne pathogens.     

Explosive increase in Salmonella java in poultry. Consequences for public health

In the Netherlands S. Paratyphi B variation Java increased in poultry from less than 2% of all isolates before 1996 up to 40% in 2001. This development in poultry runs in parallel with that in Germany and appears not to occur in other European countries. A German study shows that in the late nineties it concerns isolates of only one multi-resistant clone of Java (in Holland as well) whilst isolates before the middle nineties were genetically much more heterogeneous and sensitive to antibiotics. Although the exposition of humans to contaminated poultry meat is relatively high, human patients with a Java infection are rare. Treatment of poultry flocks with quinolones was about 13% in 2000-2001. Resistance to flumequin of Java increased from 3% between 1996-1999 to 20% between 2000-2002 whilst that of other serotypes in poultry remained about 7%. Java is also fast becoming less sensitive to ciprofloxacin which is the antibiotic of first choice in serious cases of salmonellosis. The ministries of public health, agriculture and the production boards, with their research institutes, together with the poultry meat production chain integrations have recently decided to work together in order to determine the public health importance of the Java epidemic in poultry and finding measures for effective control in the poultry industry.     

Evaluation of the SNAP foal IgG test for the semiquantitative measurement of immunoglobulin G in foals

The SNAP Foal IgG test (IDEXX) as evaluated for its accuracy and usefulness by measuring blood samples collected from 42 foals between 24 and 48 hours after birth. The results were compared with the single radial immunodiffusion (SRID) test as the reference method. The SNAP test was quick and easy to perform, and the results were similar to those obtained by SRID in 64 per cent of the samples. The best results were found with low (< 400 mg/dl) and high (> 800 mg/dl) concentrations of immunoglobulin G, with an accuracy of 80 per cent and 89 per cent, respectively. The intermediate concentrations were usually lower when measured by the SNAP test than by the SRID test, possibly owing to the variable volume of blood added to the test with the sample loop.     

Salmonella enterica subspecies enterica serotype Typhimurium and Escherichia coli O86 in wild birds at two garden sites in south-west Scotland

Salmonella enterica subspecies enterica serotype Typhimurium and Escherchia coli O86:K61:NM are two bacteria that can cause outbreaks of mortality in garden birds visiting bird tables and other feeding stations. Two sites in south-west Scotland were monitored for the two organisms for 12 months. At site A, large numbers of birds fed throughout the year, and at site B smaller numbers of birds fed only in the winter months. Samples of composite faeces were collected from the feeding stations and screened for the organisms, and any dead birds were also screened. S Typhimurium definitive type (DT) 56 (variant) was found to be endemic at site A, and was recovered from 48 per cent of samples of composite faeces collected from the bird table, from 42 per cent of composite faeces from underneath a hanging feeder, and from 33 per cent of composite faeces from below a roost used by house sparrows; the organism was also isolated from the carcases of six wild birds found dead at the site. In contrast, S Typhimurium (DT41) was recovered only once at site B, from 2 per cent of the composite faeces from below a hanging feeder, and no dead birds were recovered from the site. E coli O86 was not recovered from the faeces collected from either site, but was isolated from a bird that died from trauma at site A.