Restoring the Sagebrush Component in Crested Wheatgrass–Dominated Communities

Monotypic stands of crested wheatgrass (Agropyron cristatum [L] Gaertm. and Agropyron desertorum [Fisch.] Schult.), an introduced grass, occupy vast expanses of the sagebrush steppe. Efforts to improve habitat for sagebrush-associated wildlife by establishing a diverse community of native vegetation in crested wheatgrass stands have largely failed. Instead of concentrating on a diversity of species, we evaluated the potential to restore the foundation species, Wyoming big sagebrush (Artemisia tridentata spp. wyomingensis [Beetle & A. Young] S. L. Welsh), to these communities. We investigated the establishment of Wyoming big sagebrush into six crested wheatgrass stands (sites) by broadcast seeding and planting seedling sagebrush across varying levels of crested wheatgrass control with glyphosate. Planted sagebrush seedlings survived at high rates (～ 70% planted sagebrush survival 3 yr postplanting), even without crested wheatgrass control. However, most attempts to establish sagebrush by broadcast seeding failed. Only at high levels of crested wheatgrass control did a few sagebrush plants establish from broadcasted seed. Sagebrush density and cover were greater with planting seedlings than broadcast seeding. Sagebrush cover, height, and canopy area were greater at higher levels of crested wheatgrass control. High levels of crested wheatgrass control also created an opportunity for exotic annuals to increase. Crested wheatgrass rapidly recovered after glyphosate control treatments, which suggests multiple treatments may be needed to effectively control crested wheatgrass. Our results suggest that planting sagebrush seedlings can structurally diversify monotypic crested wheatgrass stands to provide habitat for sagebrush-associated wildlife. Though this is not the full diversity of native functional groups representative of the sagebrush steppe, it is a substantial improvement over other efforts that have largely failed to alter these plant communities. We also hypothesize that planting sagebrush seedlings in patches or strips may provide a relatively inexpensive method to facilitate sagebrush recovery across vast landscapes where sagebrush has been lost.     

Reduction of bacterial infections in newly hatched chicks by the use of antimicrobial dips: Preliminary approaches

Summary

Bacteriological examination of hatchery waste eggs, identification of the isolated bacteria, and susceptibility testing against seven antimicrobial agents were used in an attempt to establish a rational basis for reducing bacterial infections in newly hatched chicks.

Chloramphenicol at 1000 ppm was selected as the antibiotic for preliminary dipping trials and 0.45% iodophore (Wescodyne) was added for later trials. The control treatment consisted of formaldehyde fumigation. The following conclusions can be drawn:

(1) Hatchery waste eggs are highly contaminated (69.1%) and enterobacteriaceae predominate (26.6%).

(2) Chloramphenicol is the most effective antimicrobial tested.

(3) Dip treatments with either chloramphenicol alone or chloramphenicol plus Wescodyne result in a reduced percentage of abnormal navels (8.4% and 10.4%), as compared with 21.9% for the control treatment.

(4) Hatchability of either group of dipped eggs is reduced in comparison with fumigated eggs.

(5) Dip treatment with chloramphenicol plus Wescodyne significantly reduces the anal carrier rates for Escherichia coli, Pseudomonas aeruginosa, Salmonella spp., and Staphylococcus aureus. This treatment reduces the incidence of bacterial infection in abnormal navels to zero.     

The molecular epidemiology of equine influenza in Ireland from 2007-2010 and its international significance

Reasons for performing the study: Antigenic and genetic drift of equine influenza (EI) virus is monitored annually by the Expert Surveillance Panel (ESP), which make recommendations on the need to update vaccines. Surveillance programmes are essential for this process to operate effectively and to decrease the risk of disease spread through the international movement of subclinically infected vaccinated horses. Not only is surveillance necessary to inform vaccine companies which strains are in circulation, but it serves as an early warning system for horse owners, trainers and veterinary clinicians, facilitating the implementation of appropriate prophylactic and control measures. Objective: To summarise the genetic analysis of EI viruses detected in Ireland from June 2007 to January 2010. Methods: The HA1 gene of 18 viruses was sequenced and phylogenetic analysis undertaken. Results: All viruses belonged to the Florida sublineage of the American lineage. Clade 2 viruses predominated up to 2009. The viruses identified on 4 premises in 2007 displayed 100% nucleotide identity to A/eq/Richmond/1/07, the current clade 2 prototype. The first clade 1 virus was identified in November 2009 and, thereafter, clade 1 viruses were responsible for all the outbreaks identified. The Irish clade 1 viruses differ from the clade 1 virus responsible for the EI outbreaks in Japan and Australia in 2007. No virus of the Eurasian lineage was isolated during this surveillance period. Conclusions: In 2010 the ESP recommended that the vaccines should not include a H7N7 virus or a H3N8 virus of the Eurasian lineage but that they should contain both a clade 1 and clade 2 virus of the Florida sublineage. The surveillance data presented here support these recommendations and indicate that they are epidemiologically relevant. Potential relevance: These data also serve as a scientific basis for investigating the source of epizootics and outbreaks both nationally and internationally.     

Polymelous layer chick displaying additional malformations of the hind gut: case report and in-depth review of related literature

A case report of a male 6-day-old male layer chick featuring incomplete polymelia of the hind limbs and hindgut malformations is presented. The chick was submitted to computed tomography (CT) examination and subsequent anatomical dissection. Apart from the two supernumerary hind limbs, the anatomical dissection revealed additional hindgut alterations: three uniform-sized caeca flanked the ileum, and the rectum branched into paired cloacae. The supernumerary hind limbs were localized caudal to the normal hind limbs in an inverted position and were attached to pelvic girdle elements and to a curtate pygostyle. They featured a prominent unpaired femur besides paired tibiotarsi, tarsometatarsi and species-specific phalanges of the toes. Additionally, two separate bones attached to the caudoventral aspect of the regular hip bones were developed. The supernumerary limbs were in part mobile and received nerve and vascular supply. Digital 3D-reconstruction based on the CT datasets revealed the osseous components of the malformed body parts. The possible morphogenesis including an in-depth literature review and the clinical implications of the reported malformations are discussed.     

Effects of stress on endocrine and metabolic processes and redirection: cross talk between subcellular compartments

Recent advances in genome analysis and biochemical pathway mapping have advanced our understanding of how biological systems have evolved over time. Protein and DNA marker comparisons suggest that several of these systems are both ancient in origin but highly conserved into today's evolved species. However, remnants of some of the more ancient functions of these chemical systems can run in conflict with the functions that those same pathways serve in complex organisms and tissue systems today. Relevant to the present topic, nitric oxide (NO) and superoxide anion (O₂^•−), ancient cellular molecules in evolutionary terms, are recognized today as both necessary for the well-being and stable health of cells but also injurious to cells as elaborated in conjunction with the cellular stress response. Why the dichotomy? This question underlies one of the basic issues challenging researchers as well as practitioners in their approach to disease management. The fundamental proinflammatory response of the innate immune system of the host is needed for pathogen control but can be injurious to tissues from “collateral damage” from NO- and O₂^•−-derived reactive molecules capable of affecting protein function via post-translational chemical modification. This review highlights newer aspects of the biochemistry of the NO- and O₂^•−-mediated innate proinflammatory response and further show how protein and tissue damage via overproduction of reactive nitrogen and oxygen intermediary molecules such as peroxynitrite (ONOO⁻) might be targeted to specific epitopes of proteins. Changes in the regulation of metabolism in response to proinflammatory disease states are discussed for GH signal transduction and tissue specificity.     

Is a single force plate adequate for stabilographic analysis in horses?

Reasons for performing study: Postural balance can be quantified using stabilographic variables derived from force plate data that describe movements of the horse's centre of pressure (COP) in the horizontal plane. Most force plates are not large enough to accommodate all 4 limbs of a standing horse, so the study was designed to assess whether representative stabilographic data could be collected from the forelimbs or hindlimbs. Objective: To determine whether stabilographic data from either the forelimbs or the hindlimbs were representative of data for the total body. Methods: Stabilographic data (960 Hz) were collected from 17 sound horses standing with the forelimbs and the hindlimbs on separate force plates. To increase variability in the data, horses were of different sizes, the recording duration was varied (15–60 s) and data were collected under sighted and blindfolded conditions. Results: Correlation matrices indicated that total body stabilographic variables were highly significantly correlated with both forelimb and hindlimb data but correlation coefficients were higher for forelimb data. Forward stepwise regression selected forelimb data for inclusion in the model for 15/16 variables, the exception being mean absolute mediolateral velocity. Conclusions: Ground reaction force data from a pair of limbs, preferably the forelimbs, can be used to measure variables that represent total body postural balance in sound standing horses. Potential relevance: Stabilographic data from either the forelimbs or hindlimbs may be useful for detecting and quantifying deficiencies in postural balance in ataxic horses.     

Thermoregulation of the testicle in response to exercise and subsequent effects on semen characteristics of stallions

Stallions (n = 8) were implanted with a thermal sensory device in the muscle of the neck and the subcutaneous tissue of the scrotum and then assigned to either a nonexercise (Non-EX; n = 4) or exercise (EX; n = 4) group. A motorized equine exerciser was used to work EX stallions 30 min/d for 4 d/wk during a 12-wk period from July through October 2010. Temperatures (subcutaneous scrotal, intramuscular neck, and rectal) were recorded at 0, 22, and 30 min after the start of exercise, as well as 60 and 120 min post-exercise. Hourly ambient temperature and relative humidity data were also obtained. Semen was collected at 0, 4, 8, and 12 wk and analyzed for volume, sperm concentration, total sperm numbers, percentages of total and progressively motile sperm, sperm morphologic characteristics, and sperm DNA quality. No effect (P > 0.05) of exercise was observed on any of the measured semen variables. Implantation of thermal sensory devices had no demonstrable acute or chronic effects on the scrotal or neck tissue, indicating that the thermal sensory devices are a safe and effective way to measure subcutaneous scrotal and neck temperatures. At 22 and 30 min of exercise, rectal and neck temperatures increased (P < 0.0001) approximately 1.9 and 2.4°C, respectively, and scrotal temperatures simultaneously increased, although not significantly (P = 0.33), approximately 0.8°C. Correlations existed between scrotal, neck, rectal, and ambient temperatures, with the correlation between scrotal and rectal temperatures being greatest (r(s) = 0.76; P < 0.0001). Although moderate exercise for a short duration in extreme heat and humidity did significantly increase core body temperatures in stallions, scrotal temperatures did not significantly increase, and sperm parameters were unaffected.