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.     

Soil Physicochemical Changes Following Buffelgrass Establishment in Mexico

Clearing brush from rangeland and seeding it to buffelgrass (Cenchrus ciliaris L.) is a popular range improvement practice in Mexico, but no data are available on the effects of these practices on soil properties. Twenty-nine study sites were randomly selected across 3 major climatic regions in Mexico: 13 in the northwest, 11 in the northeast, and 5 in the southeast. Soils under buffelgrass stands more than 10 years old and on adjacent virgin rangelands were sampled at 0-10, 10-20, and 20-30 cm depths to quantify sand, silt, clay, organic C, total N, pH, EC, CEC, available P, and exchangeable Ca2+, Mg2+, Na+, and K+.Because soil variables were not significantly (P 0.05) different among depths, only data from the surface horizon received further analysis. Soils in the northwest had higher (P 0.05) sand content and were particularly low in total N (0.08%), Ca2+, and K+, while soils of wetter and warmer southeast Mexico were significantly (P 0.05) higher than the other two regions in measures of soil fertility such as organic C (10 times higher), total N, and CEC (both at least 3 times higher). Long-term buffelgrass establishment had the most effect on soils in the southeast and no significant effect (P0.1) on soils of northeast Mexico. Soil organic C and total N both declined (P 0.025) by about 40% under buffelgrass pastures in the southeast; excgangeable Ca2+ decreased (P=0.027) by 21% in the same region, and Mg2+ declined (P=0.03) by 36% under buffelgrass in the northwest. Soil P did not respond to buffelgrass establishment. The findings of this study suggest that high forage yields following conversion of rangeland to buffelgrass pasture will be less sustainable in subtropical regions with high rainfall (mean of 1070 mm in this study) than in the semiarid zone with inherently poorer soils.     

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。     

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.     

贺兰山西坡森林主要种群关系及其动态研究

本文从种群的相关与生态位重叠研究入手,揭示了贺兰山西坡森林生态系统中主要种群的相互作用程度和性质,从而找到了该区森林群落发生发展的内在动力。为进一步合理利用贺兰山森林资源、充分发挥其以理水为主导的系统功能奠定了种群关系的研究基础,也提供了可能的调节途径。     

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.     

气象因子与羊草生长高度的关系研究——以内蒙古草甸草原区为例

为研究1990—2017年内蒙古草甸草原羊草生长高度与主要气象因子之间的关系,根据内蒙古草甸草原气候特点,选取呼伦贝尔市牧业气象试验站1990—2017年历年5月1日—8月31日各旬降水、温度、日照时数及其相应累加值等6个水热环境参数变量,以及同期同地区羊草生长高度监测数据,建立羊草生长高度与主要气象因子关系模型,对羊草高度与气象因子之间的关系进行相关与回归分析。结果表明,羊草生长高度与返青日期呈负相关,与5月中旬降水量、6月中旬日照时数、5月1日—6月20日降水总量呈正相关;5月1日—6月20日降水总量可以影响到7月中旬羊草高度,是影响羊草高度年内最高值的重要气象因子;以旬为单位通过逐步回归的方法建立了各旬羊草生长高度与气象因子的关系模型。研究结果为该地区草地植物生长动态变化研究提供了基础数据。