Dispersal strategies of juvenile pike (Esox lucius L.): Influences and consequences for body size,somatic growth and trophic position

Individual variability in dispersal strategies, where some individuals disperse and others remain resident, is a common phenomenon across many species. Despite its important ecological consequences, the mechanisms and individual consequences of dispersal remain poorly understood. Here, riverine Northern pike (Esox lucius) juveniles (age 0+ (young-of-the-year) and 1+ years) were used to investigate the influence of body size and trophic position (at capture) on the dispersal from off-channel natal habitats and the subsequent consequences for body sizes, specific growth rate and trophic position (at recapture). Individuals that dispersed into the river (“dispersers”) were not significantly different in body size than those remaining on nursery grounds (“stayers”). For trophic position, 0+ dispersers were of significantly lower trophic position than stayers, but with this not apparent in the 1+ fish. Following dispersal into the river, the dispersers grew significantly faster than stayers and, on recapture, were significantly larger, but with no significant differences in their final trophic positions. Early dispersal into the river was, therefore, not associated with early dietary shifts to piscivory and the attainment of larger body sizes of individuals whilst in their natal habitats, contrary to prediction. These results suggest that despite an increasing risk of mortality for individuals dispersing early from natal areas, there are long-term benefits via elevated growth rates and, potentially, higher fitness. Such early dispersal behaviour could be driven by early competitive displacement.     

Ultrasonographic evaluation of the coxofemoral joint region in young foals

The objective of this study was to investigate the effect of xylazine on the stress and pain response of lame cows undergoing claw treatment in lateral recumbency (LR). Twenty-four lame, German Holstein-Friesian cows were included in a prospective, blinded, placebo-controlled clinical case study. Cows were randomly allocated to two groups (n=12) and either treated with xylazine (0.05 mg/kg BW, i.m.) or an equal volume of saline (controls) 15 min before placing them in LR. Before surgical treatment, each cow received retrograde intravenous local anaesthesia (LA). Over a period of 6h, heart rate (HR), respiratory rate (RR), plasma concentrations of cortisol, glucose, lactate and non-esterified fatty acids (NEFA) were determined at preset time intervals and the animals' behaviour was recorded via video recording and pedometer. All xylazine-treated cows showed signs of mild sedation, a reduced pain response on insertion of the needle for LA, reduced ear flicking during surgery, reduced lameness score and longer standing periods as well as improved appetite in the first hour postoperatively. Mean HR and RR, as well as plasma concentrations of NEFA were significantly reduced after xylazine treatment. Cortisol concentrations were significantly lower in xylazine-treated cows after being placed in LR but were similar to controls during surgery. The use of a low dose of xylazine in the analgesic protocol for the treatment of lame cows in LR alleviates stress and potentiates the analgesic effects of LA.     

Establishment of the European College of Veterinary Clinical Pathology (ECVCP) and the current status of veterinary clinical pathology in Europe

After 5 years of development, the European College of Veterinary Clinical Pathology (ECVCP) was formally recognized and approved on July 4, 2007 by the European Board of Veterinary Specialisation (EBVS), the European regulatory body that oversees specialization in veterinary medicine and which has approved 23 colleges. The objectives, committees, basis for membership, constitution, bylaws, information brochure and certifying examination of the ECVCP have remained unchanged during this time except as directed by EBVS. The ECVCP declared full functionality based on the following criteria: 1) a critical mass of 65 members: 15 original diplomates approved by the EBVS to establish the ECVCP, 37 de facto diplomates, 7 diplomates certified by examination, and 5 elected honorary members; 2) the development and certification of training programs, laboratories, and qualified supervisors for residents; currently there are 18 resident training programs in Europe; 3) administration of 3 annual board-certifying examinations thus far, with an overall pass rate of 70%; 4) European consensus criteria for assessing the continuing education of specialists every 5 years; 5) organization of 8 annual scientific congresses and a joint journal (with the American Society for Veterinary Clinical Pathology) for communication of scientific research and information; the College also maintains a website, a joint listserv, and a newsletter; 6) collaboration in training and continuing education with relevant colleges in medicine and pathology; 7) development and strict adherence to a constitution and bylaws compliant with the EBVS; and 8) demonstration of compelling rationale, supporting data, and the support of members and other colleges for independence as a specialty college. Formal EBVS recognition of ECVCP as the regulatory body for the science and practice of veterinary clinical pathology in Europe will facilitate growth and development of the discipline and compliance of academic, commercial diagnostic, and industry laboratories in veterinary clinical pathology. Future needs are in developing sponsorship for resident positions, increasing employment opportunities, increasing compliance with laboratory, training, and continuing education standards, and advancing relevant science and technology.     

Pan‐continental invasion of Pseudorasbora parva: towards a better understanding of freshwater fish invasions

In recent years, policy‐makers have sought the development of appropriate tools to prevent and manage introductions of invasive species. However, these tools are not well suited for introductions of non‐target species that are unknowingly released alongside intentionally‐introduced species. The most compelling example of such invasion is arguably the topmouth gudgeon Pseudorasbora parva, a small cyprinid species originating from East Asia. A combination of sociological, economical and biological factors has fuelled their rapid invasion since the 1960s; 32 countries (from Central Asia to North Africa) have been invaded in less than 50 years. Based on a combination of monitoring surveys (2535 populations sampled) and literature reviews, this paper aims to quantify and characterise important invasion parameters, such as pathways of introduction, time between introduction and detection, lag phase and plasticity of life history traits. Every decade, five new countries have reported P. parva introduction, mainly resulting from the movement of Chinese carps for fish farming. The mean detection period after first introduction was 4 years, a duration insufficient to prevent their pan‐continental invasion. High phenotypic plasticity in fitness related traits such as growth, early maturity, fecundity, reproductive behaviour and the ability to cope with novel pathogens has predisposed P. parva to being a strong invader. The Pseudorasbora parva invasion has provided quantitative data for the development of 1) early warning systems across different spatial scales; 2) rapid eradication programmes prior to natural spread in open systems and 3) sound risk assessments with emphasis on plasticity of life history traits.     

Decomposition and nitrogen release patterns of tree prunings and litter

Many studies have shown that agroforestry tree prunings can supply sufficient nutrients to meet crop demand, with the exception of phosphorus. The potential of these organic inputs to supply nutrients depends on their resource quality. Various indices have been developed to predict decomposition and nitrogen release patterns of tree prunings. To date the (lignin + polyphenol):N ratio seems to be the most robust ratio for predicting mass loss and nitrogen release. However, no critical value can be given because of the different methods used to analyze polyphenols. Suggested areas of future research include development of robust indices for predicting plant litter quality, decomposition patterns of belowground litter (roots), residual effects of tree biomass additions, and effects of adding mixtures of organic materials of contrasting quality. The overall challenge is to develop ways of managing organic matter decomposition to optimize short- and long-term release of nutrients and the maintenance of soil organic matter. This revised version was published online in June 2006 with corrections to the Cover Date.