Nutritional management of recurrent colic and colonic impactions

Although diagnosis and treatment of horses with colic have improved in the last 30 years, horses with recurrent colic can be a diagnostic and management challenge for both owners and veterinarians, and colic remains a high priority health concern of owners (Mellor et al. 2001 ). Nutritional management of these cases is often based on previous experience combined with recommendations from the evidence‐based literature. This review will briefly summarise the aetiologies of recurrent colic and primarily focus on evidence‐based nutritional management of colonic impactions, sand enteropathy, inflammatory bowel disease, and idiopathic recurrent colic, which is limited. Additional topics to be covered elsewhere in this series that are relevant to this topic include nutritional management of gastric ulceration, liver disease, colitis, geriatric horses, and feeding the horse pre‐ and post surgery.     

Statistical spring wheat yield forecasting for the Canadian prairie provinces

A study to forecast regional spring wheat (Triticum aestivum L.) yields on the Canadian Prairies was conducted, based on simulated daily water use and soil water contents derived from the National Drought Model. Empirical linear regression models were calibrated from 1976 to 2006 spring wheat yield data for this purpose. Potential predictors assessed were mainly those indicators related to water stress conditions at different crop growth stages. Stepwise regression and cross-validation were employed for the selection of the predictors in multivariate linear regression models used for forecasting spring wheat yields from seeding to harvest. The cross-validated “forecasts” for 1976–2006, using data up to harvest, explained 77%, 64%, 63% and 70% of yield variances, respectively, for Alberta, Saskatchewan, Manitoba and the entire Prairie region. Root mean squared error of the “forecasts” ranged from 8% to 11% of the average yields. The prediction accuracy earlier in the season was often lower than later in the season. Usable prediction accuracy was found by the middle of the growing season (around heading or anthesis), but only marginally effective at seeding time, especially so for Saskatchewan.     

Analysis of weight uniformity, content uniformity and 30-day stability in halves and quarters of routinely prescribed cardiovascular medications

Objectives

Congenital and acquired cardiac disorders are frequently diagnosed in small breed dogs and cats. In order to appropriately dose cardiovascular drugs for small patients, fractions of commercially available tablets must be prescribed. The aims of this study were to evaluate weight and content uniformity and 30-day chemical stability in halves and quarters of 11 drug formulations commonly prescribed to treat cardiovascular disorders in small breed dogs and cats.

Animals, materials and methods

Fifteen tablets from 11 drug formulations were obtained within the same lot. Tablets were split by a single operator using a commercially available pill splitter. Whole tablets, halves and quarters were weighed and stored in plastic containers. High-pressure liquid chromatography or liquid chromatography with mass spectrometry were utilized to determine drug content and repeated 30 days later to estimate chemical stability.

Results

Statistically significant weight variability, content non-uniformity and chemical degradation were found for some formulations. Digoxin showed a significant degradation that should be considered in clinical practice.

Conclusions

It appears that pill splitting is overall a relatively reliable practice; however tablets should not be split ahead of time but only immediately prior to intended usage.     

Septic peritonitis in a Percheron mare associated with Clostridium haemolyticum

This report describes an 11‐year‐old Percheron mare that presented with signs of colic and was ultimately diagnosed with bacterial peritonitis of unknown origin. Bacterial culture of a peritoneal fluid sample isolated 2 Clostridial species, one of which was strongly suspected to be Clostridium haemolyticum. The horse was markedly hypoalbuminaemic at presentation, leading to the development of low oncotic pressure and ventral oedema. The mare was administered a low molecular weight/low molar substitution hydroxyethyl starch solution in conjunction with other therapies that resulted in marked improvement of clinical signs. The purpose of this report is to describe the clinical findings associated with equine peritonitis associated with C. haemolyticum, a rarely identified pathogen in the horse. Secondly, this report serves to describe the beneficial effects of tetrastarch administration in a clinical case with severe hypoalbuminaemia and ventral oedema.     

Applying molecular genetic tools to tiger conservation

The utility of molecular genetic approaches in conservation of endangered taxa is now commonly recognized. Over the past decade, conservation genetic analyses based on mitochondrial DNA sequencing and microsatellite genotyping have provided powerful tools to resolve taxonomy uncertainty of tiger subspecies, to define conservation units, to reconstruct phylogeography and demographic history, to examine the genetic ancestry of extinct subspecies, to assess population genetic status non-invasively, and to verify genetic background of captive tigers worldwide. The genetic status of tiger subspecies and populations and implications for developing strategies for the survival of this charismatic species both in situ and ex situ are discussed.     

Tuber age as a contributory factor in the water relations of potato (solanum tuberosum L.)

Seed tuber age effects on the response of potato plants (cv Alpha) to different drought stress regimes during the pre-tuberization period were evaluated. During a slow drying cycle of approximately 2 weeks’ duration, young expanding leaves on plants grown from young or old seed tubers showed no evidence of osmotic adjustment and pre-stressing the plants did not affect this situation. Pre-stressed plants from young and old tubers possessed a higher relative water content at a zero turgor potential than unstressed plants. However, tuber age did not affect significantly the relative water content at zero turgor potential. Plants derived from young seed tubers exhibited improved drought resistance such as reduced water loss from mature leaves, a larger root/shoot dry weight ratio and possible effects on root distribution in soil.     

Factors affecting diurnal stem contraction in young Douglas-fir

Diurnal fluctuation in a tree's stem diameter is a function of daily growth and of the tree's water balance, as water is temporarily stored in the relatively elastic outer cambial and phloem tissues. On a very productive site in southwestern Washington, U.S.A., we used recording dendrometers to monitor stem diameter fluctuations of Douglas-fir at plantation ages 7 and 8 and related the fluctuations to environmental variables measured on-site. Growing-season diurnal stem contraction (DSC) averaged 0.21% of stem diameter, while dormant-season DSC averaged 0.03% of stem diameter. Maximum daily stem diameter generally occurred between 7:00 and 9:00 Pacific Standard Time (PST) and minimum stem diameter occurred between 17:00 and 20:00 PST. Diurnal stem contraction during the growing season was predicted by a model that included vapor pressure deficit and solar radiation (adjusted R² = 0.84). A similar model predicted DSC during the dormant season with an adjusted R² = 0.26. Soil water availability was high, and soil water content was not correlated with DSC. On four of the coldest winter days (mean daytime air temperature <0 °C), large decreases in stem diameter were observed. Recording dendrometers, used for continuous diameter measurements throughout the growing season, have the potential to provide important information not only on tree growth but also on a tree's water balance.     

Sulfite oxidase enzyme activity in soil

Several methods for measuring sulfite oxidases (EC 1.8.2.1 and EC 1.8.3.1) have been developed for microbial systems, but none have been systematically adopted for soils. We describe an assay method to measure sulfite oxidase in soil that is based on the use of potassium sulfite (K₂SO₃) serving as the substrate and electron donor, and potassium ferricyanide [K₃Fe(CN₆)] serving as the electron acceptor. Sulfite oxidase activity is expressed as micromoles of K₃Fe(CN)₆ reduced g^-1 soil 4 h^-1. Sulfite oxidase activity was linearly related to amount of soil in the assay (up to 3 g) and incubation time (up to 5 h). The average K _m value for K₂SO₃ serving as the substrate for the sulfite oxidase reaction in four diverse soils was 3.48 mM. The activation energy values calculated for soil sulfite oxidase ranged from 40.4 to 61.4 kJ mol^-1. The sulfite oxidase assay does not require any specialized equipment and is expected to be useful in studying biological sulfite oxidation in soils treated with sulfites or in naturally occurring soils where sulfur cycles between reduced (i.e., sulfite) and oxidized (i.e., sulfate) states due to flooding and drying.