The effect of Johne's vaccination on tuberculin testing in farmed red deer (Cervus elaphus)

AIM: To assess the degree of interference with bovine tuberculin testing in farmed red deer that vaccination of young deer with an oil-adjuvanted vs aqueous formulation of live attenuated Mycobacterium paratuberculosis Strain 316F vaccines would be likely to cause, and to compare immunological responses between vaccine formulations.

METHODS: Five-month-old red deer (n=45) were randomly allocated to three treatment groups of 15 animals, which received either no vaccine, a single 2-ml dose of an oil-adjuvanted formulation or two 2-ml doses, 6 weeks apart, of an aqueous formulation of live attenuated M. paratuberculosis Strain 316F vaccine injected subcutaneously (S/C) in the neck (Control, Oil-adjuvant Ptb, and Aqueous Ptb groups, respectively). Injection-site reactions were described and measured on Weeks 3, 6 and 9. Animals were weighed and lymphocyte transformation tests (LTT) and antibody enzyme-linked immunosorbent assays (ELISA) using avian, bovine and Johnin tuberculin were conducted on blood samples collected at Weeks 0, 6, 12, 15, 24, 27, 36 and 39. A bovine mid-cervical skin test (MCT) was applied at Week 12, and comparative cervical skin tests (CCTs) at Weeks 24 and 36. At Week 42, the animals were slaughtered at a commercial deer slaughter premises and subjected to rigorous meat inspection.

RESULTS: Two animals were eliminated at the start of the trial due to a positive cross-reaction with bovine tuberculin in the initial LTT. Almost all animals reacted to the MCT at Week 12, with mean skin thicknesses of 3.9, 2.9 and 1.0 mm for the Oil- adjuvant Ptb, Aqueous Ptb and Control groups, respectively. When the CCT was conducted at Week 24, 2/15 Oil-adjuvant Ptb, 2/14 Aqueous Ptb and 1/14 Control animals were classified as CCT-positive to bovine tuberculin. By Week 36, all animals were CCT-negative. The Oil-adjuvant Ptb vaccination resulted in high persistent levels of antibody that reacted with bovine tuberculin, compared with negligible levels in the Aqueous Ptb group.

Overall, a single dose of the Oil-adjuvant Ptb vaccine in deer stimulated a vigorous, cross-reactive immune response, evidenced by high LTT, skin-test and antibody reactions to bovine tuberculin, with both cell-mediated and humoral characteristics. By comparison, two doses of the Aqueous Ptb vaccine produced less cross-reactivity and a bias towards a cell-mediated response. The Oil-adjuvant Ptb vaccine resulted in moderate injection- site lesions that were quite persistent, whereas the Aqueous Ptb vaccine resulted in smaller nodules that regressed more quickly.

CONCLUSIONS: Vaccination of farmed deer with an oil-adjuvanted Johne's vaccine has the potential to cause significant interference with routine tuberculin skin testing. The cross-reactivity should decline with time and the CCT should be able to clear MCT-positives, but there is a risk of false-positives to the blood test for tuberculosis (BTB), due to high persistent levels of antibody. The CCT could be used as a primary skin test in vaccinated deer on some farms.

The Aqueous Ptb caused fewer problems with skin testing and produced significantly less bovine antibody than the Oil-adjuvant Ptb, but stimulated persistent cell-mediated immune responses that may provide some protection against Johne's disease.     

Nitrogen fertilisation of weeping love grass (eragrostis curvula) at Dohne

Three field trials on the nitrogen fertilisation of the Ermelo cultivar of Eragrostis curvula conducted over seven years were collated and reviewed. Dry matter yields in tons obtained from these trials, excluding first year results, were used to derive the regression equation y = 3.9 x — 0.4 x² + 1.3 for the yield response to increments of 100 lb of nitrogen per morgen per annum. This response was nearly linear up to 300 lb of nitrogen, and more than 400 lb of nitrogen was required for maximum dry matter production. The crude protein content of the herbage increased progressively with increasing rates of nitrogen. The recovery of fertiliser nitrogen varied from 51 to 70 per cent ; the latter being achieved by (he application of 300 lb of nitrogen. Ammonium sulphate produced considerably higher dry matter yields than urea or limestone ammonium nitrate when applied in a single dressing in the spring. When the nitrogen was applied in three dressings the yields from urea and LAN were increased and no longer significantly different from those due to ammonium sulphate.     

乳酸菌添加剂对青藏高原燕麦青贮品质的影响

[目的]研究乳酸菌添加剂对青贮燕麦发酵品质的影响,为燕麦的青贮提供技术条件。[方法]按0．005g／kg燕麦的添加量,将乳酸菌粉剂直接加入燕麦,采用捆裹青贮系统进行青贮。处理80d后,观察其感官特征并测定品质,与普通青贮燕麦和青刈燕麦进行比较。[结果]乳酸菌青贮燕麦的气味、色泽和手感均优于普通青贮燕麦,其pH值低于3．8,乳酸与乙酸的比值下降,乳酸占总酸的比例增加,DM、CP和Ash含量增加,NDF、ADF含量降低。[结论]乳酸菌添加剂改善了青贮燕麦的品质,所得燕麦属于优质青贮料。     

Perceptions of transcatheter device closure of patent ductus arteriosus in veterinary cardiology and evaluation of a canine model to simulate device placement: a preliminary study

Objectives

The purpose of this study was to evaluate a canine patent ductus arteriosus (PDA) model developed for practicing device placement and to determine practices and perceptions regarding transcatheter closure of PDA from the veterinary cardiology community.

Exploiting Knowledge of Pathogen Effectors to Enhance Late Blight Resistance in Potato

Late blight disease of potato, caused by Phytophthora infestans, is the most serious disease of this crop on a global scale and is thus a threat to food security. Use of resistant potato cultivars to prevent late blight does not have a very successful history, as P. infestans genotypes have overcome the deployed resistances. Thus, there is a need to identify more durable resistances, or identify and develop novel forms of resistance that exploit vulnerabilities in the biology of P. infestans. Application of molecular biology tools in P. infestans research has recently culminated in the identification of several avirulence effectors matching specific resistances in potato, the sequencing of the P. infestans genome and identification of hundreds of candidate translocated pathogen ‘RXLR’ effector proteins that may promote disease progression. Strategies for prioritising these effectors for further research are revealing those that are highly expressed during infection, difficult for the pathogen to alter rapidly, essential for P. infestans pathogenesis and recognized by resistant accessions of Solanum spp. These effector characteristics are being used to identify and characterise resistances from Solanum germplasm that may prove more durable. In addition to RXLR effectors, P. infestans also produces a broad spectrum of additional secreted proteins. These are exposed to plant cells and may potentially act to trigger resistance, either as broad spectrum pathogen-associated molecular patterns or as specific effectors of resistance. Alternatively, conserved secreted proteins may be attractive targets for novel agrichemical development. We have silenced a diverse selection of these candidate secreted proteins in P. infestans and demonstrated their effects on late blight disease development. Results from these studies are aiding a deeper understanding of P. infestans disease development and identifying potential pathogen weaknesses for exploitation in future control measures.     

The influence of drought on the survival of eggs of Austroicetes cruciata,Sauss

Ohne Zusammenfassung     

Soil microbial activity in opencast coal mine restorations

Abstract. A number of restored areas, a soil store and undisturbed areas on opencast coal mine sites, all of similar soil type, were sampled. The microbiological activity (dehydrogenase assay), nitrogen mineralization and nitrifying potentials and physico-chemical characteristics of the soils were determined. Dehydrogenase activities ranged from 140 to 580 μg TPF g^-1 24 h^-1 in undisturbed control soils, whereas the disturbed soils had activities of 10 to 220 μg g^-1 24 h^-1, with the smallest activities being recorded in the stored and most recently reinstated soil, indicating that disturbance has depressed microbial activity. Nitrogen mineralization potential was significantly affected by disturbance, with a value of 18 to 26 μg inorganic N g^-1 21 d^-1 in the soil store and 38 μg^-1 21 d^-1 in a soil reinstated for six months, although the values were less than this in soils reinstated for up to six years. Nitrifying potential was not significantly less in the stored soils, being within the range of 60 to 135 μg nitrate N formed g^-1 soil 21 d^-1, which was similar to that found in the undisturbed control soil. The water-holding capacity was less in the stored soil than the undisturbed controls, and was significantly less in soil reinstated for 1.5 to 2.5 years, being only 65% of the undisturbed value (0.66 g water g^-1 soil). Ammonium content of the soil store was one hundred fold larger in the soil store than in the controls (0.6 to 1.7 μg ammonium N g^-1). The carbon contents in the control soils ranged from 4.5 to 7.2%, whereas the stored and reinstated soils had generally less amounts ranging from 1.6 to 5.8%. There was a significant and positive correlation between water-holding capacity and nitrifying potential. The implications for long-term restoration are discussed.     

Acute myelogenous leukaemia in a mare

SUMMARY: A 5-year-old Thoroughbred mare presented with a 4 week history of weight loss, fever and leukopenia. Rectally, a large active foetus, thickened spleen and an abdominal mass were palpated. Leukopenia, mild anaemia, marked thrombocytopenia and hyperfibrinogenaemia were found. Cytology and cytochemical staining of a bone marrow aspirate supported a diagnosis of acute myelogenous leukaemia. The mare deteriorated despite medical therapy and was humanely euthanased.     

Regulation of uterine estrogen receptors (ER) by beta-adrenergic stimulation in immature rats

The effects of a 3-day intramuscular (i.m.) administration of clenbuterol (25 μ.g/ Kg), propranolol (12 mg/kg), clenbuterol (25 μg/kg) plus propranolol (12 mg/ Kg) and estradiol (0.5 μg) upon the female reproductive system were investigated in immature Sprague-Dawley rats. Clenbuterol and estradiol treatments induced a significant increase in uterus weight and in relative uterus weight, whereas in the groups treated with propranolol and clenbuterol plus propranolol no differences were detected versus controls. The uterine estrogen receptor levels were significantly increased by clenbuterol administration. In the rats dosed with propranolol and clenbuterol plus propranolol, no modifications occurred in estrogen receptor concentrations when compared with control values. Uterine progesterone receptors were never significantly affected by any of the considered treatments. Data obtained indicate that clenbuterol treatment induces an increase in uterus weight and in estrogen receptor levels and that these effects are regulated by acute beta-adrenergic stimulation, as the contemporaneous administration of high doses of a beta-blocker inhibit such effects.