Atrophic rhinitis of swine--a multifactorial disease?

Atrophic rhinitis is caused by toxigenic Pasteurella multocida strains. The infection is supported by Bordetella bronchiseptica and other widespread agents and by non-infectious factors damaging the nasal epithelium. The term "infectious multifactorial disease" means in German, that ubiquitous low-virulent agents cause disease when intensified by non-infectious factors. Atrophic rhinitis does not belong to this group but is an infectious disease, caused by a specific agent and influenced by several factors.     

Genetic diversity and historic introgression in German Angler and Red Dual Purpose cattle and possibilities to reverse introgression

Recovering native uniqueness has major importance for breeds with historic introgression. The aim of the study was to estimate population genetic parameters for two local red cattle breeds from Northern Germany and to study possibilities to reverse introgression. Genealogical information consisted of 90,783 individuals for German Angler and 187,255 individuals for Red Dual-Purpose cattle breed, with additional information on sex, born, breed, status, and conventional breeding values. It is concluded that the native genetic contribution could be included as an additional trait in the total merit index in order to recover a part of the native genetic background. Native contributions should be estimated in the long term from marker data in order to account for Mendelian sampling. The maintenance of a sufficient genetic diversity of native alleles can be achieved by an advanced OCS with appropriate constraints.     

Plasma haptoglobin concentration in cattle with surgically corrected torsio uteri intrapartum

In 26 cows with surgically corrected torsio uteri intra partum, severity of disease, wound healing and secondary diseases were correlated with plasma haptoglobin concentration. The objective of the investigation was to determine, if an increased plasma haptoglobin concentration indicates the severity of disease respectively expected wound healing disorders or secondary diseases. The degree of severity of disease was determined by rectally diagnosed elasticity of the uterus before the surgery. In the present investigation, the severity of a uterine torsion intra partum could not be evaluated by determining the plasma haptoglobin concentration. In 9 of 11 days of investigation there was no significant difference in the plasma haptoglobin concentration of animals with an elastic uterus (animals with good prognosis) in contrast to cows with tight uterus (patients with poor prognosis) found. The significant differences on the 6th and 7th day post surgery are related to secondary diseases in patients with poor prognosis, which develop evidently earlier and form stronger. The correlation of all cows with--to those without secondary illnesses shows, that 10 days post surgery patients with secondary diseases have a significant higher plasma haptoglobin concentration (p < 0.05) compared to animals without secondary illnesses. No correlations existed between plasma haptoglobin concentration and wound healing in the examined cattle. A postoperatively increase of haptoglobin indicates a higher risk of secondary illnesses and complications.     

A data-driven fuzzy approach to simulate the critical shear stress of mixed cohesive/non-cohesive sediments

Purpose

The critical shear stress of cohesive and mixed cohesive/non-cohesive sediments is affected by multiple interacting physical, chemical and biological parameters. There are various mathematical approaches in the scientific literature for computing critical shear stress. However, processes that influence sediment stability are still not fully understood, and available formulas differ considerably. These discrepancies in the literature arise from random system behaviour (natural variability of the sediments), different definitions of the critical shear stress, different measurement techniques and different model frameworks (scope of the parameters, undisturbed versus artificial sediment samples). While analytical approaches fail to address the involved uncertainties, fuzzy logic-based models integrate uncertainty and imprecision.

Materials and methods

With this in mind, a data-driven neuro-fuzzy model (ANFIS) was used to determine the critical shear stress based on sediment characteristics such as wet bulk density and grain size distribution. In order to select model predictors systematically, an automated stepwise regression algorithm was applied. The database for this analysis consisted of 447 measurements of the critical shear stress originating from 64 undisturbed sediment samples.

Results and discussion

The study identified clay content as the primarily controlling variable for erosion resistance. Depending on the characteristics of the sampling location, the bulk density was also selected as a model predictor. In comparison to analytical models that are available in the scientific literature, the fuzzy model achieved higher correlation coefficients between measured and predicted data.

Conclusions

The neuro-fuzzy-model includes uncertainties of input variables and their interactions directly. Thus, it provides a reliable method for the prediction of erosion thresholds of cohesive/non-cohesive mixtures. It was also shown that this approach requires fewer measured variables as well as fewer assumptions than the models it was compared to.