Low prevalence of bovine tuberculosis in Somali pastoral livestock, southeast Ethiopia

A cross-sectional study of bovine tuberculosis (BTB) detected by the comparative intradermal tuberculin test (CIDT) was conducted in livestock of the Somali region in southeast Ethiopia??in four pastoral associations from January to August 2009. In 94 herds, each of 15 cattle, camels, and goats was tested per herd leading to a total of 1,418 CIDT tested animals, with 421 cattle, 479 camels, and 518 goats. A herd was considered positive if it had at least one reactor. Prevalence per animal species was calculated using a xtgee model for each species. The individual animal prevalence was 2.0% [95% confidence interval (CI), 0.5?C8.4], 0.4% (95% CI, 0.1?C3%), and 0.2% (95% CI, 0.03?C1.3) in cattle, camels, and goats, respectively. Prevalence of avian mycobacterium purified protein derivative (PPD) reactors in cattle, camels, and goats was 0.7% (95% CI, 0.2?C2.0%), 10.0% (95% CI, 7.0?C14.0%), and 1.9 (95% CI, 0.9?C4.0%), respectively, whereby camels had an odds ratio of 16.5 (95% CI, 5.0?C55.0) when compared to cattle. There was no significant difference between livestock species in BTB positivity. In the present study, the prevalence of bovine tuberculosis was low in Somali pastoral livestock in general and in camels and goats in particular. The high proportion of camel reactors to avian PPD needs further investigation of its impact on camel production.     

非晶态木质纳米纤维素机械特性的建模

为提高对以木纤维为填充材料的复合材料的理解和性能分析,对木质纳米纤维素中的非晶态结构进行分子建模与拉伸变形仿真研究.通过对纳米纤维素非晶态结构进行周期性边界条件建模,在能量最小化和热平衡后,基于ReaxFF力场用开源代码程序LAMMPS对模型进行拉伸变形仿真,模拟原子间的相互作用,对其数据结果采用MATLAB进行后处理分析,并采用可视化开源软件Atomeye对变形过程进行监控.通过所建模型仿真研究数据,可以计算得到木质纳米纤维素纳观尺度的机械特性,求得纳观结构中应力一应变曲线,将其同实验数据相比较,用于预测材料宏观尺度各特性以及本构关系.该研究为今后分析高分子聚合物和纤维素的纳米微观界面相容性打下基础,能更好地理解高分子纤维聚合材料的力学性能.     

Two novel and potentially endemic species of Phytophthora associated with episodic dieback of Kwongan vegetation in the south‐west of Western Australia

Two novel homothallic species of Phytophthora causing dieback of Kwongan vegetation in south‐west Western Australia are described here as Phytophthora arenaria sp. nov. and Phytophthora constricta sp. nov. DNA sequencing of the ITS rDNA and cox1 gene confirmed that P. arenaria and P. constricta are unique species residing in ITS clades 4 and 9, respectively. Phytophthora arenaria has been isolated from vegetation occurring on the northern sandplains which are warmer and drier than the southern sandplains from which P. constricta has been predominantly isolated, and both species appear morphologically and physiologically well adapted to the ecosystems in which they occur. Both species have been associated mainly with dead and dying Banksia species and the pathogenicity of both P. arenaria and P. constricta to Banksia attenuata was confirmed in this study. The combination of unique DNA sequences, including considerable variation in cox1 sequence data, thick oospore walls and physiological characteristics that appear to be adaptations favouring survival in the harsh Kwongan ecosystem suggest that these species may be endemic to Western Australia.     

Welfare indicators during broiler slaughtering

1. The aim of this study was to identify the most relevant welfare indicators for unloading, lairage, stunning, killing and post-mortem inspection in a poultry slaughter plant. Different indicators were unloading duration, lairage time, environmental variables in the lairage facilities, shackling time and electrical variables used in the water bath.

2. Lairage time did not correlate strongly with dead on arrival. Heat stress was limited by means of ventilation systems, correct cage placement and appropriate stocking density per crate. The acceptable shackling period was about 30 s.

3. The presence of a corneal reflex showed that an animal was alive, while spontaneous wing flapping, spontaneous eye blinking and response to a painful stimulus were regarded as indicators of stunning efficiency.

4. It was concluded that the presence of recent traumatic injuries during the post-mortem inspection could be a valid means to establish whether corrective measures concerning the handling, transport and loading procedures should be taken.

     

Evaluation of a Whole Blood Glutaraldehyde Coagulation Test for the Detection of Failure of Passive Transfer in Calves

The accuracy of a commercially available whole blood glutaraldehyde clot test in the detection of failure of passive transfer (serum immunoglobulin [Ig]G₁ < 1,000 mg/dL) in neonatal calves was evaluated. Serum samples were obtained from 242 calves ranging in age from 1 to 8 days, and comparisons were made with serum lgG₁ concentrations determined by radial immunodiffusion. Both the sensitivity and specificity of the currently marketed whole blood glutaraldehyde clot test are inadequate for routine diagnostic use. Concerns regarding test sensitivity are the most problematic. Sensitivity varied from 0.41 to 0.00, depending on the choice of test endpoint. Specificity varied from 0.85 to 1.00, depending on the choice of test endpoint. Regression analysis demonstrated that the relationship between serum lgG₁ concentration and the glutaraldehyde clot results, although significant (P< .10), was of negligible biological relevance ( r ² = .034). J Vet Intern Med 1996; 10:82–84. Copyright © 1996 by the American College of Veterinary Internal Medicine .     

A new approach to understanding the impact of circadian disruption on human health

Background  

Light and dark patterns are the major synchronizer of circadian rhythms to the 24-hour solar day. Disruption of circadian rhythms has been associated with a variety of maladies. Ecological studies of human exposures to light are virtually nonexistent, however, making it difficult to determine if, in fact, light-induced circadian disruption directly affects human health.     

Alleviation of salt stress by arbuscular mycorrhizal in zucchini plants grown at low and high phosphorus concentration

With the aim of determining whether the arbuscular mycorrhizal (AM) inoculation would give an advantage to overcome salinity problems and if the phosphorus (P) concentration can profoundly influence zucchini (Cucurbita pepo L.) plant responses to AM, a greenhouse experiment was carried out with AM (+AM) and non-AM (−AM). Plants were grown in sand culture with two levels of salinity (1 and 35 mM NaCl, giving electrical conductivity values of 1.8 and 5.0 dS m⁻¹) and P (0.3 and 1 mM P) concentrations. The percentages of marketable yield and shoot biomass reduction caused by salinity were significantly lower in the plants grown at 0.3 mM P, compared to those grown at 1 mM P. However, even at high P concentration, the absolute value of yield and shoot biomass of +AM zucchini plants grown under saline conditions was higher than those grown at low P concentration. The +AM plants under saline conditions had higher leaf chlorophyll content and relative water content than −AM. Mycorrhizal zucchini plants grown under saline conditions had a higher concentration of K and lower Na concentration in leaf tissue compared to −AM plants. The P content of zucchini leaf tissue was similar for +AM and −AM treatments at both low and high P concentrations in the saline nutrient solution. The beneficial effects of AM on zucchini plants could be due to an improvement in water and nutritional status (high K and low Na accumulation).     

Circadian light

The present paper reflects a work in progress toward a definition of circadian light, one that should be informed by the thoughtful, century-old evolution of our present definition of light as a stimulus for the human visual system. This work in progress is based upon the functional relationship between optical radiation and its effects on nocturnal melatonin suppression, in large part because the basic data are available in the literature. Discussed here are the fundamental differences between responses by the visual and circadian systems to optical radiation. Brief reviews of photometry, colorimetry, and brightness perception are presented as a foundation for the discussion of circadian light. Finally, circadian light (CL_A) and circadian stimulus (CS) calculation procedures based on a published mathematical model of human circadian phototransduction are presented with an example.     

Serum haptoglobin concentration in cattle

To obtain a basal concentration of serum Haptoglobin (Hp) in cattle in Taiwan, Hp concentrations were measured from serum samples collected from 10 healthy heifers, every week for one year. The values were also compared with those collected from 15 cows diagnosed with postpartum metritis. The heifers were successfully impregnated by artificial insemination six months after the tests. Hp concentrations were also measured in the serum collected from 11 other cows within 3 weeks after parturition. The Hp assay developed in this study gave a good correlation (r=0.893)with Western blotting. The Hp concentration of 454 serum samples from the 10 heifers had a mean value of 83.6 +/- 34.1 mg/l, and there was no significant difference among individual heifers. The basal value of Hp in heifers was calculated as less than 73.6 mg/l. No significant difference in Hp concentration was observed among the 10 heifers during cold and warm seasons (19.8 +/- 2.2 degrees C vs 27.3 +/- 1.4 degrees C), or before and after pregnancy. The mean serum Hp concentration from cows suffering from postpartum reproductive disorders was 1133.5 +/- 627.1 mg/l, which was significantly greater than the serum of healthy heifers and postpartum cows (104.6 +/- 61.0 mg/l) (P<0.05). These results demonstrate that Hp concentration may be a useful indicator for cows with postpartum reproductive disorders.     

Effects of dietary corticosterone on peripheral blood lymphocyte and granulocyte populations in immature domestic fowl

Four-week-old chickens were fed on diets containing 0, 5, 10, 20 and 40 mg corticosterone per kg for eight days. Packed cell volume (PCV), the numbers of granulocytes (G) and lymphocytes (L), the G:L ratio and plasma corticosterone concentration were measured. Plasma corticosterone concentration was increased by dietary corticosterone from day 2 onwards. The number of lymphocytes was increased by serial bleeding but dietary corticosterone depressed the response and caused a dose-related lymphocytopenia from day 1. There was a dose related increase in granulocytes from day 4 and a dose-related increase in G:L ratio from day 1. A dose-related increase in PCV was evident only on days 2 and 4. Correlation coefficients showed little evidence of relationships between plasma corticosterone concentrations and the recorded blood variables.