More accurate measurement of temperature in potato drills increases predicted potato cyst nematode population growth

Potato cyst nematodes (PCN) are economically important pests of potato plants worldwide that can result in yield losses exceeding 80%, with an estimated cost of £50 million annually in the United Kingdom alone. The life cycle of PCN, and in particular the hatching of eggs and development and survival of juveniles, is sensitive to temperatures in the soil. Despite this fact, relatively little is known about temperatures inside potato drills and how these may differ to temperatures in the surrounding soil. We monitored the temperature inside potato drills at 19 sites across the United Kingdom and used a published temperature-driven process-based PCN life cycle model to compare predictions of PCN population dynamics driven by these temperatures to predictions based on modelled soil temperatures derived from the HadUK-Grid climate. We found that mean soil temperatures derived from the climate model were lower than those observed inside potato drills; thus, using temperatures measured directly in potato drills resulted in increased estimates of population growth and shorter estimated generation times than when using modelled soil temperatures. This finding suggests that greater understanding of the temperature inside potato drills is required if we are to make accurate predictions about the effects of temperature on PCN populations.     

Stormwater quality improvement potential of an urbanised catchment using water sensitive retrofits into public parks

Urban stormwater management is undergoing a transition from centralised hydrologically efficient systems to collections of dispersed, multi-functional elements. In response to a better understanding of impervious surface areas, the adoption of water sensitive urban design is promising for new large urban developments. However, spatial and economic constraints prohibit its adoption in established urban areas. We explore the potential for improvement to stormwater quality if 10% of existing parks in an established urban catchment are reserved for stormwater filtration. Spatially explicit hydrologic modelling is used to model the effects of parks in an existing urban catchment in South Australia as networks of bioretention devices. The allocation of 10% of parks that cover less than 16% of the landscape for bioretention devices may result in a 62% reduction (7.8 tonnes per year) of nitrogen from stormwater. The sources and destinations of stormwater pollutants are mapped to explore the strength and weaknesses of park size and distribution within each sub-catchment. Large parks situated lower in the catchment along the main trunk, and distributed smaller parks higher along the secondary stormwater network are shown to be effectively located. The potential for increasing the utilitarian value of many public parks by demonstrating the capacity for significantly improving urban stormwater quality is illustrated in this exploratory model. Opportunities for targeted improvements to stormwater quality are examined in the discussion.     

Reproductive status in broiler breeder males is minimally affected by a mid-cycle increase in photoperiod

1. Broiler breeder males were reared on 8-h photoperiods, transferred to 12 h at 20 weeks, and either maintained on 12 h or further transferred to 14, 16, 18, 20 or 22 h at 40 weeks to determine whether reproductive status and the timing of the onset of adult photorefractoriness is influenced by photoperiod during the breeding cycle. 2. No photoperiodic effect was observed on sperm concentration although the combination of large variation within a treatment and the lack of a semen sample from some males at each collection may have masked small differences and indicates that perhaps fertility in individual males fluctuates naturally during the breeding season. 3. The rate of comb growth to, and testicular weights at, 60 weeks were not significantly different between treatments. 4. Plasma testosterone concentration at 60 weeks of age declined linearly with photoperiod between 12 and 22 h, suggesting that in the birds exposed to the more stimulatory photoperiods after 40 weeks, hypothalamic-pituitary-gonadal activity shut down earlier. 5. An increase in photoperiod at 40 weeks of age appears to advance the onset of photorefractoriness in male broiler breeders, evident from the decline in testosterone concentration with increasing photoperiod; it is however insufficient to affect sperm concentration or comb area.     

Pandemic H1N1 influenza virus in Chilean commercial turkeys with genetic and serologic comparisons to U.S. H1N1 avian influenza vaccine isolates

Beginning in April 2009, a novel H1N1 influenza virus caused acute respiratory disease in humans, first in Mexico and then around the world. The resulting pandemic influenza A H1N1 2009 (pH1N1) virus was isolated in swine in Canada in June 2009 and later in breeder turkeys in Chile, Canada, and the United States. The pH1N1 virus consists of gene segments of avian, human, and swine influenza origin and has the potential for infection in poultry following exposure to infected humans or swine. We examined the clinical events following the initial outbreak of pH1N1 in turkeys and determined the relatedness of the hemagglutinin (HA) gene segments from the pH1N1 to two H1N1 avian influenza (AI) isolates used in commercial turkey inactivated vaccines. Overall, infection of turkey breeder hens with pH1N1 resulted in -50% reduction of egg production over 3-4 weeks. Genetic analysis indicated one H1N1 AI vaccine isolate (Alturkey/North Carolina/17026/1988) contained approximately 92% nucleotide sequence similarity to the pH1N1 virus (A/Mexico/4109/2009); whereas, a more recent AI vaccine isolate (A/ swine/North Carolina/00573/2005) contained 75.9% similarity. Comparison of amino acids found at antigenic sites of the HA protein indicated conserved epitopes at the Sa site; however, major differences were found at the Ca2 site between pH1N1 and A/ turkey/North Carolina/127026/1988. Hemagglutinin-inhibition (HI) tests were conducted with sera produced in vaccinated turkeys in North Carolina to determine if protection would be conferred using U.S. AI vaccine isolates. HI results indicate positive reactivity (HI titer > or = 5 log2) against the vaccine viruses over the course of study. However, limited cross-reactivity to the 2009 pH1N1 virus was observed, with positive titers in a limited number of birds (6 out of 20) beginning only after a third vaccination. Taken together, these results demonstrate that turkeys treated with these vaccines would likely not be protected against pH1N1 and current vaccines used in breeder turkeys in the United States against circulating H1N1 viruses should be updated to ensure adequate protection against field exposure.     

Determination of serum biochemistry reference intervals in a large sample of adult greyhounds

Background : As large breed, highly muscled dogs, greyhounds are regarded as physiologically different to other breeds. Biochemistry reference intervals have previously been determined using small numbers of greyhounds or based on the observations from racing dogs. Objectives : The purpose of this study was to develop statistically defined reference intervals for biochemical analytes in healthy non‐racing greyhounds. Partitioning according to gender was also examined. Methods : Biochemical analytes from a population of non‐racing healthy greyhounds, including 269 males, 202 females and 28 dogs where gender had not been recorded, were examined using a non‐parametric statistical approach. The dogs were aged between one and nine years old. Results : Total protein, albumin, globulin and creatinine reference intervals differed from generic reference intervals used for dogs. The reference intervals for greyhounds in this study are similar to those obtained by other studies of greyhounds, but often had a narrower range of values, likely reflecting more accurate estimation associated with larger numbers of reference individuals. Recommended methods for assessment of partitioning do not indicate a need to partition according to gender.