An assessment of Sentinel-1 synthetic aperture radar,geophysical and topographical covariates for estimating topsoil particle-size fractions

Data derived from synthetic aperture radar (SAR) are widely employed to predict soil properties, particularly soil moisture and soil carbon content. However, few studies address the use of microwave sensors for soil texture retrieval and those that do are typically constrained to bare soil conditions. Here, we test two statistical modelling approaches—linear (with and without interaction terms) and tree-based models, namely compositional linear regression model (LRM) and random forest (RF)—and both nongeophysical (e.g., surface soil moisture, topographic, etc) and geophysical-based (electromagnetic, magnetic and radiometric) covariates to estimate soil texture (sand %, silt % and clay %), using microwave remote sensing data (ESA Sentinel-1). The statistical models evaluated explicitly consider the compositional nature of soil texture and were evaluated with leave-one-out cross-validation (LOOCV). Our findings indicate that both modelling approaches yielded better estimates when fitted without the geophysical covariates. Based on the Nash–Sutcliffe efficiency coefficient (NSE), LRM slightly outperformed RF, with NSE values for sand, silt and clay of 0.94, 0.62 and 0.46, respectively; for RF, the NSE values were 0.93, 0.59 and 0.44. When interaction terms were included, RF was found to outperform LRM. The inclusion of interactions in the LRM resulted in a decrease in NSE value and an increase in the size of the residuals. Findings also indicate that the use of radar-derived variables (e.g., VV, VH, RVI) alone was not able to predict soil particle size without the aid of other covariates. Our findings highlight the importance of explicitly considering the compositional nature of soil texture information in statistical analysis and regression modelling. As part of the continued assessment of microwave remote sensing data (e.g., ESA Sentinel-1) for predicting topsoil particle size, we intend to test surface scattering information derived from the dual-polarimetric decomposition technique and integrate that predictor into the models in order to deal with the effects of vegetation cover on topsoil backscattering.     

Behavioural effects of ovariohysterectomy and oral administration of meloxicam in laboratory housed rabbits

This study aimed to develop a behaviour-based pain assessment system for rabbits following ovariohysterectomy. Behaviour was analysed to assess the severity and duration of pain induced and determine the effects of administration of meloxicam. The results suggest that pain associated with ovariohysterectomy induced changes in the frequency and duration of a number of behaviours. The most indicative was inactive pain behaviour, which was observed very infrequently prior to surgery compared to very frequently immediately following surgery. This strongly suggests that this increase is a direct response to the surgical pain and/or stress. The frequency of inactive pain behaviour also decreased over the four days post-surgery suggesting that pain is decreasing during this time. High dose meloxicam (initial 1 mg/kg followed 0.5 mg/kg/day) induced some degree of analgesia. However, higher doses of meloxicam or in combination with an opioid may be required to provide consistent analgesia in rabbits following soft-tissue surgery.     

Investigation of T-cell responses and viral mRNA persistence in lymph nodes of pigs infected with porcine rubulavirus

Selected lymphocyte subpopulations were studied and the distribution of viral mRNA were investigated during acute and persistent porcine rubulavirus (PoRV-LPMV) infection in Vietnamese pot-bellied pigs. Six pigs infected with PoRV-LPMV at 17 days of age exhibited clinical signs 7-10 days post-inoculation (pi). One infected piglet died 11 days pi while the other five recovered around day 13 pi and survived until euthanasia on day 277 pi. Increased numbers of CD8+, CD4+ and CD2+ T cells were detected during the acute phase of infection while CD8+ cells were elevated throughout the infection, including during the persistent stage. Specific antibodies against the haemagglutinin-neuraminidase protein of PoRV-LPMV were detected during persistent infection. Although infectious virus could not be recovered from tissues from any of the infected pigs at necropsy 277 days pi, PoRV-LPMV mRNA was detected in lymph nodes, pancreas and central nervous system using a nested polymerase chain reaction technique. Continued lymphocyte interaction with viral RNA may be an important factor in promoting cellular and humoral responses during persistent PoRV-LPMV infection.     

Investigation of the pruritogenic effects of histamine, serotonin, tryptase, substance P and interleukin-2 in healthy dogs

There are numerous studies of the pruritus-producing effects of histamine, serotonin, tryptase, substance P and interleukin-2 in humans and mice, but very little reported in dogs even though a common reason dogs are presented to veterinarians is pruritus. The aim of this study was to determine whether substances known to cause pruritus in humans also cause pruritus in dogs. Twenty-five clinically healthy research beagle dogs were included in the study. All dogs first received an intradermal injection of 0.05 mL saline as a control substance and were video-recorded for 20 min before and after the injection. Twenty-four hours later the dogs were randomly divided into five groups of five dogs each and randomly assigned to receive histamine, serotonin, tryptase, substance P or interleukin-2 injected intradermally each at the volume of 0.05 mL. On subsequent days, increasing concentrations of each substance were used. Before (baseline) and after the injection of each concentration of the substances, the dogs were video-recorded for 20 min. The frequency and character of pruritus episodes (scratching, licking, chewing, rubbing or rolling) were noted and these data were used for statistical analysis. The number of pruritus episodes was compared among baseline, saline and the different concentrations of each substance. The results showed that dogs did not have a significant increase in pruritic behaviour above baseline or saline after injection of any of the investigated substances (generalized linear model; P  = 0.23).     

Equine skin tumours in 20 horses resembling three variants of human melanocytic naevi

Melanocytic tumours are important in horses, especially grey horses. Intradermal common melanocytic naevi, cellular blue naevi and combined cellular blue naevi are subgroups of human melanocytic tumours, which have not been reported in horses. In this study, we describe 20 horses with skin tumours similar to these naevi of humans. These tumours represented individual skin masses in male and female horses of different breeds. Tumours resembling human intradermal common melanocytic naevi were noted in 12 horses aged between 2 and 17 years. Seven horses aged between 4 and 15 years developed cutaneous lesions similar to human cellular blue naevi. A combined cellular blue naevus-like tumour was diagnosed in a 20-year-old horse. All tumour types formed expansile, well-demarcated, non-encapsulated, symmetrical masses. Tumours similar to intradermal common melanocytic naevi were composed of nests of round and spindeloid neoplastic cells, often embedded in myxomatous stroma. Lesions resembling cellular blue naevi were formed by intradermal bundles of ovoid to elongated cells separated by collagen fibres. The combined cellular blue naevus-like tumour resembled human cellular blue naevus with in addition, an overlying junctional common melanocytic naevus. Neoplastic cells in all groups contained varying amounts of melanin pigment and were immunopositive for S100. These equine skin tumours differ from the commonly recognized equine melanocytic tumours by their cytomorphological features, random location and the absence of an increased tumour frequency in grey horses. The resemblance of these tumours to three distinct subgroups of human naevi expands the complexity of equine proliferative cutaneous melanocytic lesions.     

Different feed withdrawal times before slaughter influence caecal fermentation and faecal Salmonella shedding in pigs

The effects of different pre-slaughter feed withdrawal times (FWT) on the gastrointestinal tract (GIT) weight and the gut environment of pigs and Salmonella shedding were investigated. Trial 1 evaluated the effects under experimental conditions (feed withdrawal for 18, 30 and 36 h) and trial 2 under commercial conditions (15 and 30 h). In trial 1, the GIT weight tended to decrease (P=0.07), the caecal pH increased (P<0.0001), short-chain fatty acids (SCFA) decreased (P<0.001) and percentage of branched-chain fatty acids (BCFA) increased as FWT increased. Similar results were observed in trial 2, but Enterobacteriaceae numbers and Salmonella positive pigs tended to increase whereas lactobacilli decreased (P<0.0005) as FWT increased. The increase in FWT involved changes in the gut microbial ecosystem that could be associated with the trend of increased caecal Enterobacteriaceae and Salmonella in faeces, and may represent a higher risk of carcass contamination in cases of laceration of viscera.