Integrative approach for landscape-based graph connectivity analysis: a case study with the common frog (Rana temporaria) in human-dominated landscapes

Graph-based analysis is a promising approach for analyzing the functional and structural connectivity of landscapes. In human-shaped landscapes, species have become vulnerable to land degradation and connectivity loss between habitat patches. Movement across the landscape is a key process for species survival that needs to be further investigated for heterogeneous human-dominated landscapes. The common frog (Rana temporaria) was used as a case study to explore and provide a graph connectivity analysis framework that integrates habitat suitability and dispersal responses to landscape permeability. The main habitat patches influencing habitat availability and connectivity were highlighted by using the software Conefor Sensinode 2.2. One of the main advantages of the presented graph-theoretical approach is its ability to provide a large choice of variables to be used based on the study’s assumptions and knowledge about target species. Based on dispersal simulation modelling in potential suitable habitat corridors, three distinct patterns of nodes connections of differing importance were revealed. These patterns are locally influenced by anthropogenic barriers, landscape permeability, and habitat suitability. And they are affected by different suitability and availability gradients to maximize the best possible settlement by the common frog within a terrestrial habitat continuum. The study determined the key role of landscape-based approaches for identifying the “availability-suitability-connectivity” patterns from a local to regional approach to provide an operational tool for landscape planning.     

Effect of an inactivated bluetongue serotype 8 vaccine on semen quality in rams

The aim of this study was to determine whether a single dose of an inactivated bluetongue virus serotype 8 (BTV-8) vaccine altered semen quality in rams. Twenty sexually mature rams were assigned to three experimental groups: two groups of four animals were vaccinated and a third group of four animals was unvaccinated. The first group included rams with a history of natural BTV-8 infection in 2007 and the second and third groups included BTV-8 na?ve rams. Semen was collected prior to vaccination and for 4months post-vaccination. There were no significant differences in semen quality traits, including motility and concentration of spermatozoa, and percentages of living, normal dead and abnormal dead spermatozoa, between vaccinated and unvaccinated groups, or over time (P>0.05). The BTV-8 vaccine tested in this study did not appear to have any adverse effect on semen quality in rams.     

Population structure and linkage disequilibrium in diploid and tetraploid potato revealed by genome‐wide high‐density genotyping using the SolCAP SNP array

Genome‐wide association (GWA) mapping in potato requires high‐density genotyping. With the Illumina SolCAP potato single‐nucleotide polymorphism (SNP) array, a first tool for GWA mapping in potato became available. Thirty‐six tetraploid varieties and eight diploid breeding clones were genotyped for 8303 SNPs using this array. The objectives of our study were to examine in this set of germplasm: (i) the degree of polymorphism of the SolCAP SNPs in European germplasm, (ii) the population structure, (iii) temporal trends of genetic diversity and (iv) the genome‐wide extent of linkage disequilibrium (LD). Three‐quarters of the SNPs were polymorphic. In the principal coordinate analysis, a clear separation of tetraploid from diploid genotypes was observed, whereas no distinct subgroups among the tetraploid varieties were detected. The nonlinear trendline of the LD measure vs. the physical map distance decayed within 275 bp to an value of 0.10, indicating that theoretically, about 3 million equally distributed SNPs are required for GWA mapping in this diverse set of germplasm. As the LD decay changes with the population selected for GWA mapping, the number of required markers might be different in other germplasm.     

Uptake and nutrient balance of nitrogen,sulfur, and boron for optimal canola production in eastern Canada

Balanced plant nutrition is essential to achieve high yields of canola (Brassica napus L.) and get the best economic return from applied fertilizers. A field study was conducted at nine site‐years across eastern Canada to investigate the effects of nitrogen (N), sulfur (S) and boron (B) fertilization on canola nutrient uptake, nutrient balance, and their relationship to canola yields. The factorial experiment consisted of four N rates of 0 (N0), 50 (N50), 100 (N100), and 150 (N150) kg ha^?1, two S rates of 0 (S0) and 20 (S20) kg ha^?1, and three B treatments of 0 (B0), 2 kg ha^?1 at preplant (B2.0P), and 0.5 kg B ha^?1 foliar‐applied at early flowering stage (B0.5F). Each site‐year used the same experimental design and assigned treatments in a randomized complete block design with four replications. Fertilizer S application greatly improved seed yields at six out of nine site‐years, and the highest N use efficiency was in the N150+S20 treatment. Sulfur application generally increased seed S concentration, seed S removal, and plant total S uptake, while B fertilization mainly elevated straw B concentration and content, with minimal effect on seed yields. At the early flowering stage, plant tissue S ranged from 2.2 to 6.6 mg S g^?1, but the N : S ratio was over or close to the critical value of 12 in the N150+S0 combination at five site‐years. On average across nine site‐years, canola reached a plateau yield of 3580 kg ha^?1 when plants contained 197 kg N ha^?1, 33 kg S ha^?1 and 200 g B ha^?1, with a seed B content of 60 g B ha^?1. The critical N, S, and B values identified in this work and their potential for a posteriori nutrient diagnosis of canola should be useful to validate fertilizer requirements for canola production in eastern Canada.     

Comparison of a new blood sampling device with the vacuum tube system for plasma and hematological analyses in healthy dogs

Pediatric devices based on a capillary system may provide an alternative to vacuum tubes for canine blood sampling. The potential advantages are absence of vein collapse, limited blood volume sampled, and improved safety. The aim of this study was to compare routine plasma and hematological variables in seven healthy dogs using both techniques. Five biochemical analytes were measured, and a complete hematological examination and plasma exogenous creatinine clearance test were performed. No clinically relevant difference between the two techniques was observed for any variable or functional test assessed.     

Adjusting for heterogeneity of variance for carcass traits affects single and multiple trait selections in genetic evaluation of Japanese Black cattle

Heterogeneity of variance among subclasses of an effect is a potential source of bias in genetic evaluation. Degrees of the heterogeneity of variance among farm‐market‐year‐sex (FMYS) subclasses for carcass weight, beef marbling standard number, rib‐eye area, rib thickness and subcutaneous fat thickness were investigated in Japanese Black cattle. Consequences of adjusting for the heterogeneity on the predicted breeding values (PBVs) or on the genetic indexes derived from the PBVs of the five carcass traits were assessed. A total of 57 461 records were collected between 1997 and 2002 from steers and heifers fattened at farms across Japan. These records were grouped into 1591 FMYS subclasses. Bartlett's test showed that the degree of the heterogeneity of variance among the FMYS subclasses was sizeable in all traits (P < 0.0001). By applying a two‐step adjustment procedure it was possible to reduce the standard deviation, the coefficient of variation and the Gini coefficient of the phenotypic variances by 67.5% to 75.0% in the different traits. The applied adjustment caused a substantial re‐ranking of elite dams in the PBV for each trait as well as in the genetic index. This study provided evidence that the applied adjustment reduces the bias in the PBVs due to heterogeneous variances and increases the accuracy of bull‐dam selection.     

Juvenile mortality in captive lesser kudu (Tragelaphus imberbis) at Basle Zoo and its relation to nutrition and husbandry.

Since 1956, when the Basle Zoo (Switzerland) initiated the breeding of lesser kudu (Tragelaphus imberbis), 43% of the lesser kudu juveniles died before reaching an age of 6 mo. In this study, the objective was to obtain the pathological findings, nutritional history, and family tree information in order to evaluate the influence of husbandry on juvenile mortality in these animals. The main cause of death was white muscle disease (WMD), diagnosed in 14 cases (26%) of the deceased juveniles. Although enclosure size had remained constant and animal accessibility to the public was constantly high, both herd size and juvenile mortality had increased from 1956-2004. The diet consumed by the whole group in 2004 had deficient levels of vitamin E and selenium. The increasing linear trend of the mortality rate since the 1960s was significant, and there was a significant correlation between herd size and overall juvenile mortality. In contrast, there was no correlation between herd size and the occurrence of juvenile mortality associated specifically with WMD. Other investigated factors (sex, inbreeding, and season) had no significant effect on overall mortality up to 6 mo of age or on mortality associated with WMD. These results characterize both a dietary and a husbandry problem, and are supported by a lack of similar juvenile mortality in another facility where the diet was supplemented with vitamin E, animal numbers were kept low, and the enclosure structure offered more retreat options for the animals.