Controls of infiltration–runoff processes in Mediterranean karst rangelands in SE Spain

Semiarid karst landscapes represent an important ecosystem surrounding the Mediterranean Basin for which little is known on runoff generation. Knowledge of the sources and patterns of variation in infiltration–runoff processes and their controls is important for understanding and modelling the hydrological functions of such ecosystems. The objectives of this paper are to determine the infiltration rates and their controls in a representative mountain karst area (Sierra de Gádor, SE Spain) at micro-plots and to investigate the integrated response of rainfall on a typical hillslope. Rainfall simulations in micro-plots and natural rainfall-runoff monitoring on a hillslope were carried out complementarily. We investigated the role of soil surface components (vegetation, rock outcrop, fracture, and soil crust), topographic position, antecedent soil moisture, and rainfall characteristics in regulating infiltration–runoff processes. Results of rainfall simulation revealed the importance of vegetation cover and the presence of rock fractures in promoting the infiltration in the limestone karst landscape, while bare patches and rock outcrops acted as sources for runoff. All plots with > 50% vegetation cover had no runoff with up to 55 mm h^− 1 of simulated rain. In contrast, nearly all bare plots had runoff under the same simulated rain, with runoff coefficients ranging from 3.1 to 20.6% on dry soil surface conditions, and from 2.0 to 65.4% on wet soil surfaces. Runoff coefficients amounted to 59.0–79.5% for rock outcrops without cracks, but were drastically reduced by the presence of cracks. The surfaces with rock fragments resting on the soil (generally located in the middle of the slopes) prevented more effectively the runoff generation than those surfaces where rock fragments were embedded in the top soil. Antecedent soil moisture had significant impact on runoff generation, with wet soil having doubled runoff coefficient, shortened time to runoff, and increased runoff rate compared to the same but dry soil. Linear regressions indicated that the main controls for constant infiltration rate were the cover percentages of vegetation and litter, plus rainfall intensity; while the major controls for runoff coefficient were the bare soil and vegetation coverage, plus rainfall intensity. High infiltration rates measured at the micro-plots agreed with low intra-event runoff coefficients (mostly below 1%) observed under natural rainfalls at the hillslope. Runoff depth and coefficient at the hillslope was significantly correlated with rainfall depth, maximum hourly rainfall intensity and antecedent precipitation over 20 days (AP₂₀). During the 1.5-year monitoring period from Sep-2003 to Mar-2005, the overall infiltration was 41% of the total rainfall amount and the maximum infiltration rate was almost 94% of the largest single rainfall event. The results from this study contribute to improved understanding of the magnitude and controls of the surface runoff in semiarid karst mountain areas.     

Behavior of piglets after castration with or without carbon dioxide anesthesia

Surgical castration of male piglets without anesthesia is a routine management practice conducted on commercial pig farms. For animal welfare reasons, it would be beneficial to develop methods of practical pain relief. The objective of this study was to evaluate the effect of providing CO? anesthesia before castration on the behavior of piglets for up to 8 d after castration in comparison with piglets castrated without anesthesia. In 3 successive replicates, the behavior of 186 male piglets castrated with (n = 95) or without (n = 91) anesthesia was observed for up to 8 d after castration. All piglets in a given replicate were castrated on the same day, before 8 d of age. Behavioral observations were carried out in accordance with a continuous focal sampling procedure that began immediately after castration and continued for a period of 1 wk. Barrows anesthetized with CO? before castration displayed more interactive behaviors during the overall observation period than the other barrows (P = 0.0412), which may indicate better welfare. Assessing all observation periods separately, differences in activity at the udder, lying, walking, and interactive behaviors appeared to support the beneficial effect of providing CO? anesthesia before castration. However, these differences varied over time between treatment groups. The most important conclusion was that piglets castrated with or without CO? anesthesia displayed behaviors indicative of pain and discomfort for up to 6 d after castration. Therefore, additional analgesia may be necessary to eliminate the long-term pain caused by castration even in piglets anesthetized with CO? before castration.     

Leptospirosis in beef herds from western Canada: serum antibody titers and vaccination practices

One study described the frequency of pre-breeding vaccination for leptospirosis in 205 cow-calf herds from across western Canada and the prevalence of positive Leptospira antibody titers in unvaccinated, weaned calves from 61 of these herds. The percentages of herds vaccinated for leptospirosis were 13.7% in 2001 and 8.4% in 2002. Of 1539 calves examined, 13 (0.8%) had a positive antibody titer for a Leptospira serovar; the most common serovar detected was hardjo. A second study examined the prevalence of positive Leptospira antibody titers during the summer grazing season in 313 vaccinated and 478 unvaccinated cows from 40 cow-calf herds in southern Saskatchewan. Antibody titers for 7 Leptospira serovars were measured during the grazing season. Of the non-vaccinated cows, 9.6% were positive in the spring for serovar pomona, 6.7% for serovar grippotyphosa, and 6.1% for serovar icterohaemorrhagiae; the corresponding percentages for the fall were 5.5%, 3.0%, and 1.3%, respectively. Of 781 vaccinated and unvaccinated cows that were sampled twice, 11.3% of vaccinated cows and 2.3% of unvaccinated cows had increases in Leptospira antibody titers during the grazing season.     

Survey among Belgian pig producers about the introduction of group housing systems for gestating sows

There is a global move from individual to group housing of gestating sows. In the European Union, individual gestating stalls will be banned by 2013. Just like in other industrialized regions, these stalls have been the standard housing system for intensively kept sows from the 1960s onward in the Flemish region of Belgium. Because the socioeconomic consequences for the pig industry may be far-reaching and because farmer attitude may influence the realization of the hoped-for improvement in animal welfare in practice, we conducted a survey from 2003 until 2009 among representative samples of Flemish pig producers every 2 yr. The share of farms with group housing increased from 10.5% in 2003 to 29.8% in 2007, but then dropped to 24.6% in 2009. It appears that after 2005 users of old group housing systems in particular stopped farming. Because sow herd size increased more on farms with vs. without group housing and because the proportion of the herd that was group-housed also tended to increase between 2003 to 2009, the change to group housing took place faster when expressed at the level of the sow (from 9.1% in 2003 to 34.1% in 2009) instead of farm. The percentage of farmers planning to convert to group housing within 2 yr was 4.1% in 2003, and 6 to 7% thereafter. These were typically young farmers (P = 0.006) with a large sow herd (P < 0.001) and with a likely successor (P = 0.03). Free access stalls were the most common group housing system (31% of farms, 37% of sows). Their popularity is expected to increase further at the expense of electronic feeding stations, ad libitum feeding, and stalls/troughs with manual feed delivery. User satisfaction was generally high but depended on whether or not all gestating sows were kept in group (P < 0.001), the provisioning of environmental enrichment (P = 0.057), and the age (P = 0.012) and type (P = 0.016) of system. The main criteria for choosing a certain group housing system were the investment costs and sow health and welfare. The importance of economic reasons (P = 0.007) and type of labor (P = 0.043) decreased with the age of the system. In 2003 and 2005 the main reason for not having converted to group housing was that farmers would stop keeping sows by 2013. In 2007 and 2009 the reasons mainly concerned uncertainty about the future and maximally delaying the conversion. Belgium is one of the European Union countries where the pig industry is expected to undergo drastic changes during the few years remaining before the ban on individual housing.     

Lack of efficacy of low-dose spironolactone as adjunct treatment to conventional congestive heart failure treatment in dogs

Aldosterone plays an important role in the pathophysiology of heart failure. Aldosterone receptor blockade has been shown to reduce morbidity and mortality in human patients with advanced congestive left ventricular heart failure. This study was designed to assess the efficacy and tolerance of long-term low-dose spironolactone when added to conventional heart failure treatment in dogs with advanced heart failure. Eighteen client-owned dogs with advanced congestive heart failure due to either degenerative valve disease (n=11) or dilated cardiomyopathy (n=7) were included in this prospective, placebo-controlled, double-blinded, randomized clinical study. After initial stabilization including furosemide, angiotensin-converting enzyme inhibitors, pimobendan and digoxin, spironolactone at a median dose of 0.52 mg/kg (range 0.49-0.8 mg/kg) once daily (n=9) or placebo (n=9) was added to the treatment, and the dogs were reassessed 3 and 6 months later. Clinical scoring, echocardiography, electrocardiogram, systolic blood pressure measurement, thoracic radiography, sodium, potassium, urea, creatinine, alanine aminotransferase, aldosterone and aminoterminal atrial natriuretic propeptide were assessed at baseline, 3 and 6 months. Survival times were not significantly different between the two treatment groups. Spironolactone was well tolerated when combined with conventional heart failure treatment.     

Differences between the ovine tonsils based on an immunohistochemical quantification of the lymphocyte subpopulations

In sheep, the pharyngeal first defence line against oral and inhaled antigens is organized in six tonsils. Since tonsils are regarded as secondary lymphoid tissue and part of the acquired immune system which is subjected to induction through contact with antigens, an evaluation of the different lymphocyte populations in tonsils is useful to determine a tendency of the specific tonsils to more inductive or more effective immunity. By means of immunohistochemistry, different lymphocyte populations were quantified and localized using a panel of eight antibodies, i.e. anti-CD45, anti-CD21, anti-CD2, anti-CD3, anti-CD4, anti-CD8, anti-WC1 and anti-Ki67. The CD21+ B lymphocytes were localized within the tonsillar lymphoid follicles. The CD2+/CD3+ T lymphocytes were numerous in the interfollicular regions and were aligned underneath and within the epithelium but were also observed at the CD21+ pole of the lymphoid follicles. Near the lingual and tubal tonsils, and the tonsil of the soft palate, the CD45+ cells around the seromucous glands and in the lamina propria were mainly CD3+ T cells. In all tonsils, the WC1+ gamma delta T cells formed a small lymphocyte population which harboured the lamina propria and the interfollicular region. The relative percentages of the different lymphocyte populations of the large palatine and pharyngeal tonsils, which are macroscopically the most developed, were comparable. In contrast, the lingual tonsil was significantly different from the other tonsils not only by its small size and lack of lymphoid follicles, but also by the lymphocyte populations. Based on the lymphocyte populations, the ovine tonsils can be divided in three groups with the tonsil of the soft palate, the tubal and paraepiglottic tonsil forming an intermediate between the palatine and pharyngeal tonsils as true tonsils on the one side, and the lingual tonsil as a scattered lymphocyte aggregation on the other side.     

Feasibility of the Ussing chamber technique for the determination of in vitro jejunal permeability of passively absorbed compounds in different animal species

The aim of this study was to assess the feasibility of the Ussing chamber technique for the determination of the jejunal permeability of passively absorbed, high permeability model compounds (acetaminophen and ketoprofen) in different animal species. Additionally, electrophysiological measurements and histological examination of pre- and post-incubation tissue specimens were performed. Apparent permeability coefficients of turkey and dog jejunum were low and highly variable due to tissue fragility caused by differences in thickness of the remaining intestinal layers after stripping and resulting in severe damage. Pig and horse jejunum were markedly more suitable for permeability determinations and mild signs of deterioration were noticed after 120 min of incubation. Transepithelial electrical resistance and potential difference did not correlate well with the observed tissue damage. From these data, the Ussing chamber technique appears to allow for permeability measurements within a species, but seems unsuitable for interspecies permeability comparison. However, further validation of the method with low permeability compounds and actively transported compounds is needed.     

Absence reduction in entomological surveillance data to improve niche-based distribution models for Culicoides imicola

Data-driven models for the prediction of bluetongue vector distributions are valuable tools for the identification of areas at risk for bluetongue outbreaks. Various models have been developed during the last decade, and the majority of them use linear discriminant analysis or logistic regression to infer vector-environment relationships. This study presents a performance assessment of two established models compared to a distribution model based on a promising ensemble learning technique called Random Forests. Additionally, the impact of false absences, i.e. data records of suitable vector habitat that are, for various reasons, incorrectly labelled as absent, on the model outcome was assessed using alternative calibration-validation schemes. Three reduction methods were applied to reduce the number of false absences in the calibration data, without loss of information on the environmental gradient of suitable vector habitat: random reduction and stratified reduction based on the distance between absence and presence records in geographical (Euclidean distance) or environmental space (Mahalanobis distance). The results indicated that the predicted vector distribution by the Random Forest model was significantly more accurate than the vector distributions predicted by the two established models (McNemar test, p<0.01) when the calibration data were not reduced with respect to false absences. The performance of the established models, however, increased considerably by application of stratified false absence reductions. Model validation revealed no significant difference between the performance of the three distinct Culicoides imicola distribution models for the majority of alternative stratified reduction schemes. The main conclusion of this study is that the application of Random Forests, or linear discriminant analysis and logistic regression on the condition that calibration data were first reduced on geographical or environmental information, potentially lead toward better vector distribution models.     

Morphological changes in the small intestinal smooth muscle layers of horses suffering from small intestinal strangulation. Is there a basis for predisposition for reduced contractility?

Reasons for performing study: Intestinal strangulation often leads to enterectomy after which ileus can develop. This has prompted research to look into possible pathophysiological processes triggering equine ileus. However, morphological changes of the small intestinal smooth muscle in relation to equine colic have not yet been studied. Objectives: The presence of some smooth muscle proteins was morphologically assessed and quantified in control and colic horses. In addition, the up‐ or down‐regulation of heat shock proteins (HSP20 and HSP27) influencing the contractility of smooth muscles was studied. Methods: Cranial resection margins of 18 strangulated small intestinal samples were collected. Small intestinal control samples were collected from 11 horses subjected to euthanasia for other than gastrointestinal‐related reasons. Formaldehyde‐fixed tissue was paraffin‐embedded and processed for conventional staining and immunohistochemistry. Snap‐frozen full‐thickness biopsies were collected for western blot analyses. Results: Evaluating the muscle layer microscopically, colic samples showed significantly more signs of degradation than controls (P = 0.026) of which vacuolar degeneration was most prominent (P = 0.009). In colic samples, myosin protein levels were decreased (P = 0.022) whereas desmin (P = 0.049) and HSP20 protein levels (P = 0.005) were elevated. Conclusions: In colic samples, microscopic lesions at the level of the muscle layer indicate a stress response. In addition, modified amounts of structural proteins such as myosin and desmin together with increased HSP20 levels could perhaps provide a basis for explaining the malfunctioning of the intestinal muscle layer. Potential relevance: Post operative ileus, following small intestinal strangulation and resection, could be related in part to a dysfunctional muscle layer. In addition to microscopic signs of degeneration, myosin and HSP20 were affected. Pharmacological interventions might alter HSP20 expressions and thus serve a protective effect.