Pulmonary gas exchange and plasma lactate in horses with gastrointestinal disease undergoing emergency exploratory laparotomy: a comparison with an elective surgery horse population

Objective: To characterize pulmonary gas exchange and arterial lactate in horses with gastrointestinal disease undergoing anesthesia, compared with elective surgical horses, and to correlate these variables with postoperative complications and mortality. Study Design: Prospective clinical study. Animals: Horses undergoing emergency laparotomy for acute intestinal disease (n=50) and healthy horses undergoing elective surgery in dorsal recumbency (n=20). Methods: Arterial blood gas analysis was performed at predetermined intervals on horses undergoing a standardized anesthetic protocol. Alveolar–arterial oxygen gradient was calculated. Predictive factors for postoperative complications and death in colic horses were determined. Results: Arterial oxygen tension (P_aO₂) varied widely among horses in both groups. P_aO₂ significantly increased in the colic group after exteriorization of the ascending colon. P_aO₂ and alveolar–arterial oxygen gradient were not significantly different between groups, and neither were correlated with horse outcome. Arterial lactate in recovery ≥5 mmol/L was associated with a 2.25 times greater relative risk of complications and lactate ≥7 mmol/L was associated with a 10.5 times higher relative risk of death. Conclusion: Colic horses in this population were not more likely to be hypoxemic than elective horses, nor was gas exchange impaired to a greater degree in colic horses relative to controls. Arterial lactate sampled immediately after anesthetic recovery was predictive for postoperative complications and death.     

Persistent spatial clusters of plasmacytosis among Danish mink farms

Aleutian disease (Plasmacytosis) is caused by the Aleutian mink disease virus (AMDV), an autonomous parvovirus and affects many mustelid species, including the American mink (Neovisonvison). In Denmark, an eradication program reduced the prevalence of test-positive farms from 100% in 1976 to 15% in 1996. Nevertheless, the disease persists in the Vendsyssel district of Northern Jutland, despite the eradication efforts. In this study, we used spatial epidemiological analysis to test for spatial autocorrelation of the distribution of farms positive for the disease. We investigated 2375 farms in Denmark (342 of which were located in the Vendsyssel district), during the period 2000-2008. For the purpose of our study, a farm was considered positive when, on any test conducted in a year, at least three animals were tested positive. To detect spatial clusters, we performed a retrospective analysis with spatial scan statistics. We performed one analysis for each of the nine years (2000-2008). A separate analysis was conducted with only the farms in Vendsyssel included. The spatial cluster analysis revealed a significant cluster throughout the time period studied in Northern Jutland. The only exception was 2002 when an outbreak was detected in the southern part of Jutland, and not in the north. The farm-level prevalence of the disease in Denmark was highest in this year, suggesting that the outbreak in the south could have masked the persistent signal from the north; the northern cluster was still significant when analysing only the Vendsyssel populations. These results confirm that Northern Jutland continues to have a significantly higher number of cases than expected if the disease was randomly distributed.     

Glyphosate and glufosinate-based herbicides: fate in soil,transfer to,and effects on land snails

Purpose  

The aim of this work was to assess the transfer and effects of two widely used herbicides on the land snail Helix aspersa during long-term exposure under laboratory conditions.     

Effects of dobutamine on cardiovascular function and oxygen delivery in standing horses

Dobutamine is routinely used to improve cardiovascular function in anaesthetized horses. However, dobutamine in conscious horses is insufficiently investigated. Ten research horses that were already instrumented for a preceding trial were included into the study. Cardiovascular variables were recorded and blood samples taken after instrumentation (Baseline), before starting dobutamine and after 10 min of dobutamine infusion (2 µg kg⁻¹ min⁻¹). A significant increase in systemic blood pressure, mean pulmonary artery pressure and right atrial pressure, and a decrease in heart rate were observed with dobutamine compared with baseline measurements. Arterial and mixed venous haemoglobin and oxygen content, as well as mixed venous partial pressure of oxygen increased. No significant changes in cardiac output, stroke volume, systemic vascular resistance, arterial partial pressure of oxygen, or oxygen consumption, delivery and extraction ratio were detected. Concluding, dobutamine increased systemic blood pressure without detectable changes in stroke volume, cardiac output or systemic vascular resistance in conscious horses.     

Effects of nitrogen fertilization and irrigation on N2O emissions from a sandy soil in Germany

The aim of this study was to investigate the effect of supplemental irrigation on the amount of N₂O emissions on a sandy soil in north-east Germany. N₂O flux measurements were carried out over two vegetation periods from the emergence of plants to harvest. The level of N₂O emissions was low, which is typical for sandy soils in north-east Germany. In both periods, irrigation had no increasing effect on N₂O emissions. Relevant factors were the soil temperature and the soil water-filled pore space (WFPS), which were mainly influenced by weather conditions. This may indicate that nitrification was the main source of N₂O emissions. In conclusion, this study has confirmed that sandy soils under weather conditions of north-east Germany generally have a very low potential for N₂O emissions.     

Factors that affect the demand for potato products in the United States

A demand model was developed to determine the factors that affect the demand for potato products in the United States. The following market components were analyzed: potato chips; dehydrated-foodservice; dehydrated-retail; fresh; frozen-foodservice; and frozen-retail. Equations were estimated for each of the six components via ordinary least squares. Factors found to affect demand were population, consumer price index, consumer income, consumer debt, retail potato product price, females in the labor force, percentage of households with microwave ovens, restaurant meal expenditures, price of substitute potato products, price of complement products, and advertising expenditures. The demand for all of the potato products was found to be inelastic, but fresh demand was the most inelastic.     

Assessing nitrogen fixation in mixed- and single-species plantations of Eucalyptus globulus and Acacia mearnsii

Mixtures of Eucalyptus globulus Labill. and Acacia mearnsii de Wildeman are twice as productive as E. globulus monocultures growing on the same site in East Gippsland, Victoria, Australia, possibly because of increased nitrogen (N) availability owing to N(2) fixation by A. mearnsii. To investigate whether N(2) fixation by A. mearnsii could account for the mixed-species growth responses, we assessed N(2) fixation by the accretion method and the (15)N natural abundance method. Nitrogen gained by E. globulus and A. mearnsii mixtures and monocultures was calculated by the accretion method with plant and soil samples collected 10 years after plantation establishment. Nitrogen in biomass and soil confirmed that A. mearnsii influenced N dynamics. Assuming that the differences in soil, forest floor litter and biomass N of plots containing A. mearnsii compared with E. globulus monocultures were due to N(2) fixation, the 10-year annual mean rates of N(2) fixation were 38 and 86 kg ha(-1) year(-1) in 1:1 mixtures and A. mearnsii monocultures, respectively. Nitrogen fixation by A. mearnsii could not be quantified on the basis of the natural abundance of (15)N because such factors as mycorrhization type and fractionation of N isotopes during N cycling within the plant confounded the effect of the N source on the N isotopic signature of plants. This study shows that A. mearnsii fixed significant quantities of N(2) when mixed with E. globulus. A decline in delta(15)N values of E. globulus and A. mearnsii with time, from 2 to 10 years, is further evidence that N(2) was fixed and cycled through the stands. The increased aboveground biomass production of E. globulus trees in mixtures when compared with monocultures can be attributed to increases in N availability.     

Microbial biomass estimations in soils from tussock grasslands by three biochemical procedures

Microbial biomass was determined by three biochemical procedures in nine topsoils from a climosequence in tussock grasslands. The pH values of the samples ranged from 4.4 to 6.2 and organic C contents from 2.5 to 20.0%. When determined by a chloroform-fumigation procedure, contents of biomass C and mineral-N (Min-N) flush ranged from 530–2780 and 59–167 μgg^?1 dry soil respectively. Adenosine 5'-triphosphate (ATP) content ranged from 2.2 to 10.7 μg g^?1 dry soil. All three estimates were significantly correlated with each other and with several soil properties, including organic C and total N contents and CO₂ production. They were not significantly correlated with any climatic factor.In spite of these significant correlations, the ratios of the biomass estimates varied appreciably in the different soils. The ratios of biomass C/Min-N flush ranged from 7.8 to 22.8 (average 12.5), biomass C/ATP from 163 to 423 (average 248) and Min-N flush/ATP from 12 to 35 (average 22). These ratios were mostly higher than those found elsewhere for Australian and English soils. The high biomass C/ATP and Min-N flush/ATP ratios did not appear to originate from inefficient extraction of “native” ATP or from the soils' P status. Based on these results, care in the use of factors for obtaining soil microbial biomass content from Min-N flush or ATP values is indicated.