Managerial and environmental determinants of clinical mastitis in Danish dairy herds

Background

Several management and environmental factors are known as contributory causes of clinical mastitis in dairy herd. The study objectives were to describe the structure of herd-specific mastitis management and environmental factors and to assess the relevance of these herd-specific indicators to mastitis incidence rate.

Methods

Disease reports from the Danish Cattle Data Base and a management questionnaire from 2,146 herds in three Danish regions were analyzed to identify and characterize risk factors of clinical mastitis. A total of 94 (18 continuous and 76 discrete) management and production variables were screened in separate bivariate regression models. Variables associated with mastitis incidence rate at a p-value < 0.10 were examined with a factor analysis to assess the construct of data. Separately, a multivariable regression model was used to estimate the association of management variables with herd mastitis rate.

Results

Three latent factors (quality of labor, region of Denmark and claw trimming, and quality of outdoor holding area) were identified from 14 variables. Daily milk production per cow, claw disease, quality of labor and region of Denmark were found to be significantly associated with mastitis incidence rate. A common multiple regression analysis with backward and forward selection procedures indicated there were 9 herd-specific risk factors.

Conclusion

Though risk factors ascertained by farmer-completed surveys explained a small percentage of the among-herd variability in crude herd-specific mastitis rates, the study suggested that farmer attitudes toward mastitis and lameness treatment were important determinants for mastitis incidence rate. Our factor analysis identified one significant latent factor, which was related to labor quality on the farm.     

Risk factors for metritis in Danish dairy cows

A retrospective longitudinal study of metritis was conducted in Denmark on data collected during 1993-1994. Data on herd size, breed, parity, and treatment of disease were obtained from the Danish Cattle Database. Management and production-facility data were collected using a questionnaire, conducted as a telephone interview in 1994. The study included 2144 herds from three regions in Denmark (102,060 cows). Herd-level variables included were: herd size, housing, flooring, grazing, calving measures, and calving supervision. Cow-level variables were: parity, breed, calving season and whether the cow had been treated by a veterinarian for dystocia or the diseases: retained placenta, reproductive disease, ketosis, milk fever, or dry cow mastitis.Marginal multivariable logistic-regression analyses were performed. The cow with highest odds of metritis was a first or greater than or equal to third parity cow, of large breed, that calved during November-April, in a zero-grazing herd. The cow had been treated for dystocia, retained placenta, and at least one other reproductive disease, but not for ketosis.     

Simple and Rapid Quality Control of Sulfated Glycans by a Fluorescence Sensor Assay—Exemplarily Developed for the Sulfated Polysaccharides from Red Algae Delesseria sanguinea

Sulfated polysaccharides (SP) from algae are of great interest due to their manifold biological activities. Obstacles to commercial (especially medical) application include considerable variability and complex chemical composition making the analysis and the quality control challenging. The aim of this study was to evaluate a simple microplate assay for screening the quality of SP. It is based on the fluorescence intensity (FI) increase of the sensor molecule Polymer-H by SP and was originally developed for direct quantification of SP. Exemplarily, 65 SP batches isolated from the red alga Delesseria sanguinea (D.s.-SP) and several other algae polysaccharides were investigated. Their FI increase in the Polymer-H assay was compared with other analytical parameters. By testing just one concentration of a D.s.-SP sample, quality deviations from the reference D.s.-SP and thus both batch-to-batch variability and stability can be detected. Further, structurally distinct SP showed to differ in their concentration-dependent FI profiles. By using corresponding reference compounds, the Polymer-H assay is therefore applicable as identification assay with high negative predictability. In conclusion, the Polymer-H assay showed to represent not only a simple method for quantification, but also for characterization identification and differentiation of SP of marine origin.     

Preschool programs and later school competence of children from low-income families

At follow-up in 1976, low-income children who had attended infant and preschool programs in the 1960's had significantly higher rates of meeting school requirements than did controls, as measured by lower frequency of placement in special education classes and of being retained in grade (held back).     

Changes in mean concentration, phase shifts, and dissipation in a forced oscillatory reaction

Experiments are presented that confirm earlier predictions that the mode of supply of reactants to a nonlinear (bio)chemical reaction determines or controls concentrations at steady states far from equilibrium. The oxidation of nicotinamide adenine dinucleotide (NADH) catalyzed by the enzyme horseradish peroxidase with continuous input of oxygen was studied; NAD+ is continuously recycled to NADH through a glucose-6-phosphate dehydrogenase system. A comparison of steady-state concentrations is made with an oscillatory oxygen input and a constant input at the same average oxygen input for both modes. By varying the frequency and amplitude of the perturbation (O2 influx), the following may be changed: the average concentration of NADH; the Gibbs free energy difference delta G of the reactants and products at steady state; the average rate of the reaction; the phase relation between the oscillatory rate and delta G; and the dissipation. These results confirm the possibility of an "alternating current chemistry," of control and optimization of thermodynamic efficiency and dissipation by means of external variation of constraints in classes of nonlinear reactions and biological pumps, and of improvements of the yield in such reactions (heterogeneous catalysis, for example).     

High-resolution holocene environmental changes in the thar desert, northwestern india

Sediments from Lunkaransar dry lake in northwestern India reveal regional water table and lake level fluctuations over decades to centuries during the Holocene that are attributed to changes in the southwestern Indian monsoon rains. The lake levels were very shallow and fluctuated often in the early Holocene and then rose abruptly around 6300 carbon-14 years before the present (14C yr B.P.). The lake completely desiccated around 4800 (14)C yr B.P. The end of this 1500-year wet period coincided with a period of intense dune destabilization. The major Harrapan-Indus civilization began and flourished in this region 1000 years after desiccation of the lake during arid climate and was not synchronous with the lacustral phase.     

Amplified fragment length polymorphism- and simple sequence repeat-based molecular tagging and mapping of greenbug resistance gene Gb3 in wheat

The greenbug, Schizaphis graminum (Rondani), is the most economically damaging aphid pest of wheat in the southern Great Plains of the USA. In this study, the single, dominant greenbug resistance gene, Gb3, was molecularly tagged and genetically mapped using amplified fragment length polymorphism (AFLP) and simple sequence repeat(SSR) markers. Three AFLP loci were associated with the Gb3 locus in linkage analysis with 75 F_2:3 families from the cross between two near‐isogenic lines (NILs) for Gb3,‘TXGBE273’ and ‘TXGBE281′. Two of these loci, XMgcc Pagg and Xmagg Patg cosegregate with Gb3 in the population analysed. Further analysis indicated that XMgcc Pagg and Xmagg Patg are specific for the Gb3 locus in diverse genetic backgrounds. Two SSR markers, Xgwm111 and Xgwm428 previously mapped in wheat chromosome 7D, were shown to be linked with Gb3, 22.5 cM and 33.1 cM from Gb3, respectively, in an F₂ population of ‘Largo’בTAM 107’, suggesting that Gb3 is located in the long arm of chromosome 7D. The two AFLP markers cosegregating with Gb3 are valuable tools in developing molecular markers for marker‐assisted selection of greenbug resistance in wheat breeding.