Ecotypes of Italian ryegrass from Swiss permanent grassland outperform current recommended cultivars

Italian ryegrass (Lolium multiflorum Lam. ssp. italicum Volkart ex Schinz et Keller) thrives well in permanent grassland in mild and moist regions of Switzerland. Ecotypes of Italian ryegrass from Swiss permanent meadows have often been used successfully as the base material of breeding programmes. However, their agronomic performance per se has never been studied in detail. Therefore, field trials were conducted to assess the potential of this semi-natural genetic resource for use in breeding. Twenty ecotype populations were collected in different geographical regions in 2003 and seed was increased. Plot trials with 20 ecotype populations were conducted 2005–2007 at three locations, supplemented by row trials at two additional locations, and including four currently recommended cultivars as controls. Average performance in terms of yield, vigour and resistance to snow mould of ecotypes was superior to the cultivars. Depending on the characteristic, between three and 16 of the 20 ecotypes performed significantly better than the cultivars mean. However, resistance against crown rust of all ecotypes was significantly poorer than that of the cultivars. Correlation and regression analysis showed that more eastern and more northern collecting sites harboured better performing ecotypes. However, the most consistent site related factor favouring performance of the ecotypes in terms of yield, vigour, snow mould and Xanthomonas resistance was a low abundance of species which are typical of Arrhenatheretum type meadows. Data from the plot trials were related to results obtained with spaced plants at a single site, either in a seedling nursery or in the greenhouse. Resistance against crown rust was extremely well predicted by spaced plant observations. Xanthomonas resistance observed after artificial inoculation in the greenhouse was also significantly, but less closely correlated with field observations. An early date of ear emergence as observed on spaced plants was associated with high annual yield in the plot trials. It is concluded that in intensively managed habitats, natural selection has resulted in ecotype populations of Italian ryegrass which are highly promising for use in breeding. Individual plant selection for resistance can be expected to efficiently reduce their high susceptibility to crown rust.     

A Hierarchical Perspective to Woody Plant Encroachment for Conservation of Prairie-Chickens

Encroachment of Great Plains grasslands by fire-sensitive woody plants is a large-scale, regional process that fragments grassland landscapes. Using prairie grouse (Tympanuchus spp.) of conservation concern, we apply hierarchy theory to demonstrate how regional processes constrain lower-level processes and reduce the success of local management. For example, fire and grazing management may be locally important to conservation, but the application of fire and grazing disturbances rarely cause irreversible fragmentation of grasslands in the Great Plains. These disturbance processes cause short-term alterations in vegetation conditions that can be positive or negative, but from a long-term perspective fire maintains large tracts of continuous rangelands by limiting woody plant encroachment. Conservation efforts for prairie grouse should be focused on landscape processes that contribute to landscape fragmentation, such as increased dominance of trees or conversion to other land uses. In fact, reliance on local management (e.g., maintaining vegetation structure) to alter prairie grouse vital rates is less important to grouse population persistence given contemporary landscape level changes. Changing grass height, litter depth, or increasing the cover of forbs may impact a few remaining prairie-chickens, but it will not create useable space at a scale relevant to the historic conditions that existed before land conversion and fire suppression.     

Effects of Hormonal Supplementation on Nuclear Maturation and Cortical Granules Distribution of Canine Oocytes During Various Reproductive Stages

The aim of this study was to evaluate the effects of hCG, progesterone and oestradiol supplementation on nuclear and cytoplasmic maturation of canine oocytes cultured for 24, 48, 72 and 96 h. Oocytes obtained from 18 healthy bitches were divided into three groups according to their reproductive status (follicular, luteal and anoestrus stages) and cultured in TCM 199 + 25 UI/ml of hCG + 1 μg/ml of progesterone + 1 μg/ml of 17‐β oestradiol or without hormonal supplementation (control) for different periods. Then, they were stained with FITC‐LCA‐Hoescht for chromatin configuration and cortical granules distribution and evaluated under an epifluorescence microscope. Culture time and the influence of different stages of the oestrous cycle were also evaluated. The present study demonstrated that there was no significant difference among the reproductive stages. With regards to culture medium, only oocytes from the supplemented medium were able to complete meiosis; however, significant difference was only noticed in the percentage of MI stage oocytes (p < 0.05) in the follicular and luteal group at 72 h of culture. Most oocytes in germinal vesicle, germinal vesicle breakdown and metaphase I stage had cortical granules distributed throughout the cytoplasm (immature pattern), irrespective of the culture period (p < 0.05). Cortical granules distributed immediately beneath the plasma membrane (mature) was only observed in metaphase II stage oocytes, but not all of them presented matured cytoplasm. Our results reveal that cortical granules distribution in canine oocytes matured in vitro did not progressed in correspondence with nuclear stage changes and are in accordance with those from other species.     

Towards a Science-Based Integrated Ozone-Fine Particle Control Strategy

Epidemiology studies relating health effects to ambient levels of ozone and fine particles have led to the modification of standards in the United States for these pollutants (substitution of an 8-h standard for ozone at 80 ppbv, and addition of 24-h and annual standards for fine particles). The interrelationships of these pollutants in the atmosphere suggest the need for an integrated, science-based strategy for their control. Secondary ozone formation has been controlled through emission controls on VOC and NO_x precursors. Fine particles are secondary products largely resulting from the oxidation of precursors (SO₂, NO_x, and VOCs). The key intermediates in both types of secondary process are free radical species and the photochemically labile compounds that produce them in the atmosphere. However, due to the complex and nonlinear nature of the processes, reductions in precursors may lead to unexpected changes in ozone and fine particle formation rates. For example, reduction in NO_x emissions may reduce ozone and nitric acid levels, but lead also to increased rates of sulfate formation in clouds and increased ammonia availability for neutralization of acidic sulfate aerosols. Reductions of SO₂ may reduce aerosol sulfate levels in the summer, but have no effect in other seasons. Reductions in VOCs may reduce ozone levels in urban core areas, but not elsewhere. An integrated, regionally and seasonally specific, emission reduction strategy is needed to cost-effectively reduce both ozone and fine particle levels.     

In vitro susceptibility of avian Escherichia coli and Pasteurella multocida to danofloxacin and five other antimicrobials.

The in vitro susceptibility of Escherichia coli and Pasteurella multocida isolated from poultry was determined to danofloxacin, a novel fluoroquinolone, and five other commonly used antimicrobials. A total of 1737 E. coli field isolates and 107 P. multocida isolates were tested by veterinary diagnostic laboratories in Europe, Japan, South Africa, and North America during the period 1989-91. The antimicrobial susceptibility of these isolates was determined using the Sensititre broth microdilution technique. The minimum inhibitory concentrations (MIC) of danofloxacin, furaltadone, lincomycin, oxytetracycline, spectinomycin, and trimethoprim:sulfamethoxazole that prevented growth of 90% of the bacteria were 0.25 > 64, > 64, > 64, > 128, and > 16 micrograms/ml, respectively, against E. coli isolates and 0.25, 64, 64, 16, 128, and 8 micrograms/ml, respectively, against P. multocida isolates. Danofloxacin demonstrated considerable in vitro potency against these important poultry pathogens, many of which showed extensive resistance to the other antimicrobials tested.     

The prevalence of temporal bone fractures is high in horses with severe temporohyoid osteoarthropathy

Temporohyoid osteoarthropathy is a well‐recognized cause of equine neurologic disease. Temporal bone fractures associated with temporohyoid osteoarthropathy have been recognized with CT, however, little information is available regarding these fractures. The aims of this retrospective analytical study were to assess the prevalence of these fractures and to describe the specific configurations and associated imaging and clinical features. Fracture of the temporal bone was identified with CT in 16 of 39 included horses. All fractures were unilateral, minimally displaced and extended through the temporal bone in a rostrodorsal to caudoventral orientation. Two fracture configurations were identified: in nine cases, the fracture extended the full width of the petrous pyramid into the cranial vault and in seven cases, the fracture only extended through the lateral part of the petrous temporal bone, not involving the cranial vault. Fusion of the temporohyoid joint was present in 13 of the 16 fracture cases. Quarter Horses were over‐represented in the fractured population (14/16). All horses with fractures had ipsilateral neurologic deficits. Patient outcomes were not significantly different between temporohyoid osteoarthropathy horses with and without temporal bone fractures (P = 0.68). However, six of the nine patients with cranial vault involvement did not return to their previous use. Findings support previous studies indicating that temporal bones should be carefully assessed for concurrent fractures when temporohyoid osteoarthropathy is identified in CT images, especially when there is fusion of the temporohyoid joint. An improved awareness of specific fracture configurations will help with detection of these fractures.     

Morphology of alpaca (Vicugna pacos) embryos in the first third of pregnancy

The breeding of South American camelids is the main economic activity of the high Andean region of South America and it, is potentially, the most profitable resource in of the Puna environmental conditions of the Puna. The duration of the gestation in alpaca is 339.7 ± 12 days. The objective of the present work was to macroscopically and microscopically describe the ontogenic development of the splanchnic cavities of the alpaca and to determine the gestational time in which the post‐cranial ossification centers are observed in the embryos/fetuses of this species, from day 21 to 107 of gestation. The documentation of normal ontogenic development, which is vacant for this period, is of the utmost importance to understand the consequences of the alterations at the different gestational times, as well as for the estimation of the gestational age in the case of abortions. Forty‐seven alpaca specimens of both sexes, at different times of their gestational development, collected during slaughter at local slaughterhouses of the Department of Huancavelica, Peru, were evaluated. Specimens were assigned to seven groups according to their morphological characteristics. The embryogenesis in the alpaca was characterized by a series of changes comparable to those occurring in other mammals with similar gestational periods. Despite these similarities, species differences were found in some organs as stomach, which are observed too in adult individuals.