Comparative examination of the lateral cerebral ventricles of different dog breeds using quantitative computed tomography

Due to the great variations among the shape of the skull in different breeds, the routine use of computed tomography in the diagnosis of central nervous diseases in the dog requires basic knowledge of the structure of the inner subarachnoidal spaces. In neoplastic as well as in inflammatory brain disease, changes of the size and shape of liquor filled spaces can be found. In the present study, the easily demonstrable lateral ventricles of the brain of ten dogs of each breed, respectively, without cerebral disease belonging to the breeds German Shepherd (DSH), Dachshund, Boxer, Labrador Retriever and Toy poodle were characterized with regard to their two-dimensional expansion. The average width and height of the lateral ventricles were ascertained for each breed.The Boxer had the relatively largest lateral ventricles, whereas in the other breeds,their sizes were very similar. 32 of the dogs investigated (64%) had symmetric lateral ventricles, and in 18 dogs (36%) they were asymmetric. Of these 18 cases, the left lateral ventricle was larger in 12 dogs (67%).     

Case control study to investigate risk factors for bovine neonatal pancytopenia (BNP) in young calves in southern Germany

A case control study on farm level was conducted at the Clinic for Ruminants, LMU Munich, to identify possible risk factors associated with the observed increase in numbers of calves showing clinical signs of Bovine Neonatal Pancytopenia (BNP) since 2006 in southern Germany. Interviews were conducted between August 2008 and June 2010. The characteristics of 56 dairy farms with at least one confirmed case of BNP (thrombocytopenia and leukocytopenia and/or typical findings in post-mortem examination and bone marrow histology) were compared with those of two sets of 50 control dairy farms each, with no history of BNP. The first set of 50 control farms was selected randomly from veterinary practices which had never observed a BNP case on the farms they serviced. The second set of 50 control farms was matched by the veterinary practices which had provided case farms. Two separate analyses were conducted: (1) case farms (n=56) vs. randomly selected control farms (n=50) and (2) case farms (n=56) vs. a matched set of control farms (n=50). All variables with p<0.2 in the univariable analysis were included in stepwise logistic regression models. In the first analysis, only the use of PregSure(?) BVD vaccine was positively associated with BNP with an odds ratio of 1292 (95% CI: 114-14707). In the second analysis, conditional logistic regression models did not converge, therefore non-conditional logistic regression models were conducted. In the non-conditional analysis five variables remained in the model, three of which were negatively associated with BNP: the use of vitamin E and selenium, the frequent use of mastitis tubes, and the use of stem growth regulators in grain production. The use of prophylactic measures (such as control of parasites or vaccination of calves against respiratory disease) was positively associated with BNP with an odds ratio of 14.3 as well as the use of PregSure(?) BVD vaccine with an odds ratio of 426 (95% CI: 20-9095).     

Seasonal acclimation of photosystem II in Pinus sylvestris. I. Estimating the rate constants of sustained thermal energy dissipation and photochemistry

Acclimation of the partitioning of absorbed light energy in Photosystem II (PSII) between photochemical and non-photochemical processes includes short-term adjustments that are rapidly reversed in the dark and seasonal acclimation processes that are unaffected by dark acclimation. Thus, by using dark-acclimated leaves to study the seasonal acclimation of PSII, the confounding effect of short-term adjustments is eliminated. The maximum quantum yield of photochemistry, estimated by chlorophyll fluorescence analysis as F(v)/F(m), where F(v) = (F(m) - F(o)), and F(m) and F(o) are maximum and minimum chlorophyll fluorescence, respectively, has been widely used to follow the seasonal acclimation of PSII, because it is measured in dark-acclimated leaves. Seasonal changes in F(v)/F(m) can be caused by adjustments in either the photochemical capacity in PSII, or the capacity of thermal dissipation in PSII, or both. However, there is a lack of chlorophyll fluorescence parameters that can distinguish between these processes. In this study, we introduce two new parameters: the rate constants of sustained thermal energy dissipation (k(NPQ)) and of photochemistry (k(P)). We estimated k(NPQ) and k(P) from dark-acclimated F(o) and F(m) measured during spring recovery of photosynthesis in Scots pine (Pinus sylvestris L.) trees. We suggest that k(NPQ) and k(P) be used to study the mechanisms underlying the observed seasonal acclimation in PSII, because these parameters provide quantitative data that complement and extend F(v)/F(m) measurements.     

Comparative motion analysis of the canine hind limb during gait on force plate and treadmill

Computer assisted gait analysis allows for the objective examination of ground reaction forces as well as the kinematic analysis of gait. At present it is unclear if there are relevant differences in the gait pattern of the hind limb of dogs during the walk on treadmill and force plate. Thus, aim of this study was the comparison of canine hind limb joint angles and certain kinematic gait cycle parameters like cadence, step and stride time as well as step length during the walk on force plate and treadmill. 19 adult dogs of different breeds were analysed. Extension and flexion of hip, stifle and hock, hip ab- and adduction and range of motion (ROM) were evaluated. Furthermore joint angles at the moment of maximum load were identified. Considering the joint angles and gait cycle parameters there were no significant differences between force plate and treadmill, except for the hip angles, the hock angle at the moment of maximum load as well as for cadence and stride time. Whereas all flexion/extension joint angles, except the maximum hock joint angle, showed a moderate to good correlation, the ROM of the analysed joint angles was in maximum moderate. In summary it could be demonstrated that the gait pattern of the canine hind limb shows similarities on force plate and treadmill. Nevertheless significant differences of certain parameters exist and in total only a fair to moderate correlation of the data between treadmill and force plate could be shown. Therefore the results of this study provide important information for the comparative interpretation of canine gait analysis carried out on force plates and treadmills.     

Modelling dead wood islands in European beech forests: how much and how reliably would they provide dead wood?

Dead wood is an important element of forests both for biodiversity and ecosystem functions. Due to intensive silviculture, however, dead wood usually is strongly underrepresented in European forests. Forest reserves cannot fully compensate for this because they comprise only a small proportion of forested areas and are often isolated. Retaining a certain number of dead trees in managed forests is important, but may cause safety problems for lumbermen and visitors and still does not necessarily lead to an amount and incidence (i.e., probability of occurrence) of dead wood that might be required for many species and certain ecosystem functions. Our studies concentrate on a third and complimentary dead wood management strategy: dead wood islands, i.e. small unmanaged islands distributed throughout managed forests. As an example, we focus on European beech forests (Fagus sylvatica). An important question related to this strategy is: how do amount, quality, and incidence of dead wood depend on the island’s size? To provide an answer, we use the spatially explicit, rule-based simulation model BEFORE-CWD that was developed to analyse dead wood dynamics in natural beech forests. This model and its predecessor, BEFORE, are well-verified and validated. They reproduce a suite of observed patterns and generate valid secondary and independent predictions. We found that islands that are too small, i.e. smaller than 0.33 and 0.08 ha for standing and lying dead wood, respectively, can fail to provide dead wood for several decades. The shape of the islands has only a minor effect. Extreme storm events temporarily increase and then decrease the amount of standing dead wood. In terms of the amount and incidence of dead wood, it makes no difference if one big or several small islands are set aside from management, unless the islands are not too small. We conclude that even relatively small unmanaged islands within managed forests can reliably provide dead wood and therefore should be considered as a management option. Our results can be used, for example by using metapopulation models of species of interest, to develop management plans for creating networks of dead wood islands.     

Organic carbon sequestration in earthworm burrows

Earthworms strongly affect soil organic carbon cycling. The aim of this study was to determine whether deep burrowing anecic earthworms enhance carbon storage in soils and decrease C turnover. Earthworm burrow linings were separated into thin cylindrical sections with different distances from the burrow wall to determine gradients from the burrow wall to the surrounding soil. Organic C, total N, radiocarbon (¹⁴C) concentration, stable isotope values (δ¹³C, δ¹⁵N) and extracellular enzyme activities were measured in these samples. Anecic earthworms increased C stocks by 270 and 310 g m^?2 accumulated in the vertical burrows. C-enrichment of the burrow linings was spatially highly variable within a distance of millimetres around the burrow walls. It was shown that C accumulation in burrows can be fast with C sequestration rates of about 22 g C m^?2 yr^?1 in the burrow linings, but accumulated C in the burrows may be mineralised fast with turnover times of only 3–5 years. Carbon stocks in earthworm burrows strongly depended on the earthworm activity which maintains continuous C input into the burrows. The enhanced extracellular enzyme activity of fresh casts was not persistent, but was 47% lower in inhabited burrows and 62% lower in abandoned burrows. Enzyme activities followed the C concentrations in the burrows and were not further suppressed due to earthworms. Radiocarbon concentrations and stable isotopes in the burrow linings showed an exponential gradient with the youngest and less degraded organic matter in the innermost part of the burrow wall. Carbon accumulation by anecic earthworm is restricted to distinct burrows with less influence to the surrounding soil. Contrary to the initial hypothesis, that organic C is stabilised due to earthworms, relaxation time experiments with nuclear magnetic resonance spectroscopy (NMR) did not reveal any enhanced adsorption of C on iron oxides with C stabilising effect. Our results suggest that earthworm activity does not substantially increase subsoil C stocks but burrows serve as fast ways for fresh C transport into deep soil horizons.     

Sexual maturity and egg production in an unexploited population of the red squat lobster Pleuroncodes monodon (Decapoda,Galatheidae) from Central America

The squat lobster Pleuroncodes monodon is one of the most common and abundant galatheid species in the deepwater fishery of Pacific coast of America. In contrast with Peru and Chile, the red squat lobster is not commercially exploited in Costa Rica. Here we estimated the size of sexual maturity and analysed egg production in P. monodon from the Pacific of Costa Rica; the results might be important for an adequate management strategy when initiating a sustainable fishery of this resource in Costa Rica. Analyses of allometric growth revealed that females and males reached their morphological sexual maturity at 26.9 and 30.4 mm CL, respectively. The percentage of immature females captured in the present study (54%) suggests that almost half of females are able to reproduce before they are caught. Egg production was positively correlated with body size; females that measured between 24.1 and 29.0 mm CL contributed roughly 90% to the offspring production of the population. Females from Costa Rica had a considerably lower average egg volume (0.039 mm³) and higher fecundity (9810) than females from Chile. In comparison to other American galatheids P. monodon from Costa Rica produces numerous but small eggs, a typical strategy of species with a prolonged larval development. An analysis between our results and information published about P. monodon from Chile also revealed differences in the size–frequency distribution shape of both populations. The non-exploited character of the Costa Rican P. monodon population and a latitudinal (temperature-related) cline in body size might be associated with these differences.     

The behavioural response of slugs and snails to novel molluscicides, irritants and repellents

The behavioural response of the slug Deroceras panormitanum (Lessona and Pollonera) and the snail Oxyloma pfeifferi (Rossm?ssler) to novel molluscicides was investigated in choice and no-choice experiments. Low-light video-recording in combination with automated tracking and event recording was used to identify the repellent and irritant effects of (1) cinnamamide, (2) copper ammonium carbonate, (3) a mulch, (4) a horticultural ground-cover matting impregnated with a copper formulation and (5) urea/formaldehyde. In the no-choice experiments the products had a stronger irritant effect on the snails than on the slugs. All products tested except the mulch significantly reduced the locomotor activity of both the slugs and snails. The most effective product, cinnamamide, reduced snail locomotor activity by 94% and track length by 96%. The overall repellent effect of the treatments in the choice experiments was stronger in the slugs; where presence, locomotor activity and track length in the treated area were significantly reduced by all products. The avoidance of treated areas exceeded 95% with the mulch (for slugs) and with copper ammonium carbonate (for snails).     

Computer tomographic differentiation of intrathoracic neoplasms and inflammation in the dog

The purpose of this study was to elaborate on the advantages and limits of computed tomography (CT) in the differentiation of thoracic lesions, in particular neoplasias. In the course of the investigation CT-scans of the thorax of 31 dogs with lesions in the area of the lungs or mediastinum were evaluated. The lesions were rated by morphology, distribution pattern, attenuation values and contrast-enhancement. Biopsies or the whole body underwent a pathohistological examination. Of the 31 dogs 17 had neoplastic and 14 had inflammatory lesions in the thoracic region. With help of the CT, the exact localisations of the different lesions was possible in most cases. Due to their characteristic morphologies, distribution patterns and attenuation values the differentiation between inflammatory and neoplastic lesions was possible in most cases (n=25/31) on the basis of the CT-scans. Mean non-enhanced CT attenuation values of the neoplastic lesions ranged between 31 and 50 HU, of the inflammatory lesions between -251 and 9 HU. Both neoplastic and inflammatory lesions showed contrast enhancement (between 14 and 38 HU and between 2 and 95 HU respectively). The mediastinal abcesses enhanced mainly on the periphery of the lesion. A differentiation of the various types of neoplastic lesions based on the non-enhanced attenuation values was not successful. Only metastasis could be differentiated because of their distribution pattern.     

Increasing dietary pectin level reduces utilization of digestible threonine intake, but not lysine intake, for body protein deposition in growing pigs

Two N balance studies were conducted to investigate the effects of feeding graded levels of pectin (a soluble nonstarch polysaccharide, NSP) on the utilization of ileal digestible threonine (Thr; Thr study) and lysine (Lys; Lys study) intake for body protein deposition (PD) in growing pigs. In each study, eight Yorkshire barrows with an average initial BW of 17.2 +/- 1.3 (Thr study) and 14.3 +/- 1.4 kg (Lys study) were fed each of five experimental diets during five subsequent experimental periods, according to a crossover design. Pigs were fed twice daily at 2.6 times maintenance energy requirements. The soybean- and cornstarch-based diets, in which either Thr or Lys was the first-limiting nutrient, were formulated to contain (as-fed basis) 0, 4, 8, or 12% pectin or 8% cellulose (water-insoluble NSP), respectively, and with NSP substituting cornstarch. Across treatments, the mean daily Thr and Lys intake were 5.42 +/- 0.04 g/d (Thr study) and 7.98 +/- 0.12 g/d (Lys study), respectively. Apparent and standardized ileal digestibilities of Thr and Lys were determined in a separate study. Mean PD was 93.4, 90.2, 82.1, 76.7, and 87.9 g/d (SEM = 1.3; Thr study) and 90.7, 88.6, 87.8, 85.3, and 88.1 g/d (SEM = 1.1; Lys study) for the five respective treatments. Utilization of ileal digestible Thr intake, but not of ileal digestible Lys intake, for PD decreased linearly with dietary pectin level, and was not influenced by diet cellulose level. The current study indicates that apparent and standardized ileal digestibility values do not provide an accurate predictor of dietary effects on the utilization of ileal digestible Thr intake for protein deposition in growing pigs fed diets containing soluble NSP.