Cardiac Power Output during Dobutamine Stress Test in Horses

Although echocardiography has greatly improved the diagnostic possibilities in equine medicine, determining the prognosis remains a difficult task. In humans, maximal cardiac power output (CPO) has been described as a powerful indicator of exercise capability and outcome in heart disease. The aim of the study is to describe the measurement of CPO by echocardiography and by thermodilution in healthy horses. Six healthy horses were studied. Cardiac output (CO) was measured by thermodilution and Doppler echocardiography at rest and during a pharmacologic stress test consisting of 35 μg/kg atropine followed by incremental steps 2, 4, 6, and 8 μg/kg/min of dobutamine infusion. Mean arterial pressure (MAP) was measured invasively by a catheter introduced into the transverse facial artery. CPO was calculated as the product of CO and MAP. Baseline CPO measured by thermodilution and by Doppler echocardiography was 10.7 ± 3.3 and 13.7 ± 4.5 watts, respectively. CPO increased significantly with pharmacologic stimulation and reached maximal CPO of 66.4 ± 3.6 and 60.4 ± 5.1 watts when measured by thermodilution and Doppler echocardiography, respectively. This study describes an estimation of CPO in horses. Further studies should demonstrate the usefulness of CPO as a predictive indicator in horses suffering from cardiac disease.     

Comparing floristic composition in treefall gaps of certified, conventionally managed and natural forests of northern Honduras

? Forest certification sets requirements for minimizing the impacts of logging on the natural structure and floristic composition of forests.

? We assessed the impact of certification by comparing the floristic composition of 52 taxa of trees and shrubs in the treefall gaps of certified, conventionally managed and protected forests in northern Honduras.

? The highest abundance of light-benefiting taxa was found in certified forests, whereas conventionally managed forests were floristically more similar to natural forests. The environmental conditions measured in certified gaps were not favourable for a natural forest floristic composition.

? Past logging may have altered the species composition in certified forests relatively more than in conventionally managed forests. This implies that the need for restoration operations should be considered in certification requirements, along with landscape-level planning to enhance post-logging recovery.

     

Water retention characteristics of coarse porous materials to construct purpose-designed plant growing media

ABSTRACT

Among potential components to construct Technosols for urban greening purposes, the commercially available geogenic coarse porous materials (CPMs) are mainly used in practice because of their high porosity. However, the knowledge of the hydraulic behavior of CPMs as well as of their mixtures with other substrates is limited, provoking their suboptimal usage. Therefore, we determined the water retention characteristics, including the available water capacity (AWC) of six geogenic CPMs: porlith, expanded shale, expanded clay, tuff, pumice, and lava. In order to obtain the water retention characteristics of the CPMs as well as of their mixture with sand (1:4 per volume), the following methods adapted from soil physics were applied over a wide range of pressure heads: Equi-pF apparatus, ceramic tension plates, pressure plate extractors, WP4C apparatus, and water vapor adsorption. The results were used to parametrize the modified Kosugi model (using SHYPFIT 2.0). Porlith and tuff have the highest AWC (0.37 m³ m^?3 and 0.17 m³ m^?3, respectively) and are the only ones which can be recommended as effective water-retaining materials. Further materials exhibit an AWC less than 0.10 m³ m^?3. The CPMs exhibit a bimodal pore size distribution, which can be well described by the applied model, except for pumice and expanded shale. The mixtures present overall low AWCs up to 0.07 m³ m^?3, with the pure sand having less than 0.03 m³ m^?3. For practical application a quite high ratio of CPM is needed, and the mixing material must be adapted to the hydraulic properties of the CPMs. The water inside the CPMs may be easily available for plant roots able to penetrate in the CPMs’ coarse pores.     

Mikro- und makroskopische Untersuchungen an Straßenbaumveredelungen im Hinblick auf die Beeinflussung ihrer Bruchsicherheit

Aim of the study was to identify changes within xylem structure of grafted trees which could possibly lead to a higher risk of breakage. Therefore, 83 trees from the genera Prunus, Sorbus, Carpinus, Quercus, Robinia and Crateagus were examined at the macro- and microscopic level. All wood samples showed changes in their xylem structure in the areas at or around the contact zone of stock and scion. Cells were deviated in different angles from the stem axis in the tangential direction. Furthermore, whirled grain areas were found adjacent to the contact zone. Abnormal xylem structures could be found in various quantum's. Despite the observed changes in the xylem structure, the risk of breakage is not significantly increased. An e-mail based survey among 496 administrations of rural districts in Germany and bigger towns all over Germany including 64 botanical gardens and arboretum, revealed only nine cases of stem breakage at the contact zone of grafted trees. These breaks were found in the genera Tilia, Fagus and Robinia. Further studies are recommended to gain more knowledge about how xylem structure develops during the lifespan of a tree under stress conditions, especially in urban environments.     

The relationship between antibody status to bovine corona virus and bovine respiratory syncytial virus and disease incidence,reproduction and herd characteristics in dairy herds

Background

Bovine respiratory syncytial virus (BRSV) and bovine corona virus (BCV) affects cattle worldwide. Our objective was to evaluate the effects of these infections on general health and reproduction parameters measurable on herd level and to explore the association between antibody status and some herd characteristics.

Methods

We collected a pooled milk sample from five primiparous cows from 79 Swedish dairy herds in September 2006. The samples were analysed for immunoglobulin G antibodies to BCV and BRSV with indirect enzyme-linked immunosorbent assays. Herd level data from 1 September 2005 to 30 August 2006 were accessed retrospectively. The location of the herds was mapped using a geographical information system.

Results

Ten herds were antibody negative to both viruses and were compared with 69 herds positive to BCV or BRSV or both. Positive herds had a higher (P = 0.001) bulk tank milk somatic cell count (BMSCC) compared with negative herds. The medians for all other analyzed health and reproductive parameters were consistently in favour of the herds negative to both viruses although the differences were not statistically significant. A higher proportion (P = 0.01) of herds used professional technicians for artificial insemination, rather than farm personnel, amongst the 33 herds negative to BCV compared with the 46 positive herds.

Conclusions

Our result shows that herds that were antibody positive to BCV and/or BRSV had a higher BMSCC compared with herds negative to BCV and BRSV. There was also tendency that negative herds had a better general herd health compared with positive. A higher proportion amongst the BCV negative herds used external technicians for AI instead of farm personnel, indicating that it is possible to avoid infection although having regular visits. Negative herds were located in close proximity to positive herds, indicating that local spread and airborne transmission between herds might not be of great importance and that herds can stay free from these infection transmission although virus is circulating in the area.     

Alopecia areata in Eringer cows

Alopecia areata is a hair loss disorder in humans, dogs and horses with a suspected autoimmune aetiology targeting anagen hair follicles. Alopecia areata is only sporadically reported in cows. Recently, we observed several cases of suspected alopecia areata in Eringer cows. The aim of this study was to confirm the presumptive diagnosis of alopecia areata and to define the clinical phenotype and histopathological patterns, including characterization of the infiltrating inflammatory cells. Twenty Eringer cows with alopecia and 11 Eringer cows without skin problems were included in this study. Affected cows had either generalized or multifocal alopecia or hypotrichosis. The tail, forehead and distal extremities were usually spared. Punch biopsies were obtained from the centre and margin of alopecic lesions and normal haired skin. Histological examination revealed several alterations in anagen hair bulbs. These included peri‐ and intrabulbar lymphocytic infiltration, peribulbar fibrosis, degenerate matrix cells with clumped melanosomes and pigmentary incontinence. Mild lymphocytic infiltrative mural folliculitis was seen in the inferior segment and isthmus of the hair follicles. Hair shafts were often unpigmented and dysplastic. The large majority of infiltrating lymphocytes were CD3⁺ T cells, whereas only occasional CD20⁺ lymphocytes were present in the peribulbar infiltrate. Our findings confirm the diagnosis of T‐cell‐mediated alopecia areata in these cows. Alopecia areata appears to occur with increased frequency in the Eringer breed, but distinct predisposing factors could not be identified.