Validation of triaxial accelerometers to measure the lying behaviour of adult domestic horses

Examining the characteristics of an animal’s lying behaviour, such as frequency and duration of lying bouts, has become increasingly relevant for animal welfare research. Triaxial accelerometers have the advantage of being able to continuously monitor an animal’s standing and lying behaviour without relying on live observations or video recordings. Multiple models of accelerometers have been validated for use in monitoring dairy cattle; however, no units have been validated for use in equines. This study tested Onset Pendant G data loggers attached to the hind limb of each of two mature Standardbred horses for a period of 5 days. Data loggers were set to record their position every 20 s. Horses were monitored via live observations during the day and by video recordings during the night to compare activity against accelerometer data. All lying events occurred overnight (three to five lying bouts per horse per night). Data collected from the loggers was converted and edited using a macro program to calculate the number of bouts and the length of time each animal spent lying down by hour and by day. A paired t-test showed no significant difference between the video observations and the output from the data loggers (P=0.301). The data loggers did not distinguish standing hipshot from standing square. Predictability, sensitivity, and specificity were all >99%. This study has validated the use of Onset Pendant G data loggers to determine the frequency and duration of standing and lying bouts in adult horses when set to sample and register readings at 20 s intervals.     

Selective grazing of acyanogenic white clover: Variation in behaviour among populations of the slug Deroceras reticulatum

Summary Collections of the slug Deroceras reticulatum were made from grassland sites containing contrasting frequencies of the cyanogenic morph of white clover, Trifolium repens. In choice chamber experiments, slugs obtained from sites with a low frequency of cyanogenic clover showed a significantly greater degree of selective eating of acyanogenic morphs than slugs taken from a site containing a high frequency of cyanogenic clover. Differences in selectivity between populations were caused both by differences in the rate of initiation of feeding on cyanogenic morphs, and by differences in the extent of damage once feeding had been initiated. The implications of these results for the cyanogenic polymorphism of T. repens are discussed.     

黄河靖南峡-黑山峡河段的生态敏感性

基于GIS空间分析、栅格运算与叠加及RS图像地物提取方法,针对黄河靖南峡-黑山峡河段存在的水土流失、土地沙漠化和土壤盐渍化等生态问题,开展了单因子生态问题敏感性和综合生态敏感性分析.研究表明：中、高度生态敏感区几乎覆盖研究区整个流域,包括景泰县五佛乡、靖远县北湾镇以北和乌兰镇、糜滩乡、东湾镇、三滩乡及平川区的陡城到红柳滩一带;针对高、中和轻度敏感性区域,相应地将研究区规划为禁止开发建设区、中度开发建设区和深度开发建设区.在区域水电开发过程中,应采取积极保护措施,以实现流域生态环境的可持续发展.     

Social learning and the development of individual and group behaviour in mammal societies

As in human societies, social learning may play an important role in shaping individual and group characteristics in other mammals. Here, we review research on non-primate mammals, concentrating on work at our long-term meerkat study site, where longitudinal data and field experiments have generated important insights into the role of social learning under natural conditions. Meerkats live under high predation pressure and occupy a difficult foraging niche. Accordingly, pups make extensive use of social information in learning to avoid predation and obtain food. Where individual learning is costly or opportunities are lacking, as in the acquisition of prey-handling skills, adults play an active role in promoting learning through teaching. Social learning can also cause information to spread through groups, but our data suggest that this does not necessarily result in homogeneous, group-wide traditions. Moreover, traditions are commonly eroded by individual learning. We suggest that traditions will only persist where there are high costs of deviating from the group norm or where skill development requires extensive time and effort. Persistent traditions could, theoretically, modify selection pressures and influence genetic evolution. Further empirical studies of social learning in natural populations are now urgently needed to substantiate theoretical claims.     

Diet selection and performance of cattle and horses grazing in heathlands

As the number of horses is steadily increasing in Cantabrian less-favoured areas, mostly occupied by nutritionally poor heathland communities, the objective of this research was to study and compare diet selection and performance of crossbred horses and beef cattle (Asturiana de los Valles breed) grazing these areas during the summer. A total of 20 cows (seven lactating their calves and thirteen dry) and 20 mares (eight lactating their foals and twelve dry) were managed during 3 years on a heathland area from June to September and October. The proportion of grass (mostly Pseudarrhenatherum longifolium) and heather (Erica umbellata, E. cinerea and Calluna vulgaris) in the diet selected by cows and mares was estimated in two occasions (July and September) each year using the alkane markers. All animals were weighed at the beginning, middle and end of the summer grazing season. Mares selected heath grasses and rejected heather species more than did the cows (P < 0.001), particularly in early summer (0.85 v. 0.65 herbage proportion in July; 0.63 v. 0.55 in September). Lactating state did not affect diet composition. Mares achieved more favourable (P < 0.001) body weight (BW) changes than cows, but there was also an interaction with season (P < 0.001). From June to August, cows lost BW, being the daily changes (in percentage of initial BW) -0.15%/day in lactating and -0.05%/day in dry cows, whereas both lactating and dry mares gained BW (0.16 and 0.12%/day, respectively). From August to October, lactating cows and mares lost more BW (P < 0.01) compared with their non-lactating counterparts (-0.19 v. -0.10%/day in cows, -0.14 v. -0.05%/day in mares). With regard to the offspring, BW gains between June and August were similar in calves and foals (0.83 and 0.90%/day, respectively), but thereafter calves achieved higher (P < 0.05) BW gains than foals (0.37 v. 0.16%/day). It is concluded that the low nutritive quality of these heathlands restricts, both cattle and horse performance, even during short summer grazing season, being more penalized lactating animals, especially the cows. Although calves were able to maintain acceptable growth rates, foals showed reduced ones during the second half of the grazing season. Other plant communities with better nutritive quality should be provided to assure replenishment of body reserves in dams, and enhance offspring gains to maintain sustainable grazing systems with productive herds of cattle and horses in these heathland areas.     

Variability in individual animal's intake of minerals offered free-choice to grazing ruminants

A review of the literature indicates that there is very little published information on the variation in intake of minerals and other supplements offered free-choice to grazing animals. Most of the studies have been conducted with molasses feedblocks and liquid licks and the data indicate large day to day and among animal variation. A computer recording system has been developed and tested which allows for more information to be collected with regard to frequency of consumption of free-choice supplements by grazing animals. Studies have been conducted with molasses blocks and loose mineral supplements provided to grazing cattle. Results indicate that the supplements were consumed by almost all animals on a regular basis. However, there was considerable variation among animals in the quantity of supplement consumed. For the molasses blocks daily intake averaged 1.2 ± 0.6 kg per head within a range of 0.72–1.65 kg. For the mineral supplement the average daily consumption was 135 ± 55 g per head within a range of 50–300 g. The supplement feeders were visited every hour of the day but approximately 40% of the visits occurred in the late evening. Information on the behavioural pattern of consumption may enable strategies to be developed which could reduce the variation in consumption.     

A novel high throughput 96-well-based fluorimetric method to measure amikacin in pharmaceutical formulations: development using response surface methodology

An aminoglycoside antibiotic, amikacin, is used to treat severe and recurring bacterial infections. Due to the absence of a chromophore, however, amikacin must be extensively derivatized before being quantified, both in analytical and bioanalytical samples. In this study, for the first time, we developed a simple and sensitive method for measuring amikacin sulfate using spectrofluorimetry with a 96-well plate reader, based on the design of the experiment's approach. To develop a robust and reproducible spectrofluorimetric method, the influence of essential attributes, namely pH of the buffer, heating temperature, and concentration of reagents, were evaluated using univariate analysis followed by multivariate analysis (central composite design). International Conference of Harmonization guidelines were used to validate the optimized method. The developed technique is linear from 1.9 to 10 μg/ml with a regression coefficient of 0.9991. The detection and quantification limits were 0.649 μg/ml and 1.9 μg/ml, respectively. For the developed method, both intraday and interday precision (%RSD) were less than 5%. Using the method, amikacin concentrations were quantified in prepared amikacin liposomes and commercial formulations of Amicin®. The developed method greatly reduces sample volume and is a rapid, high throughput microplate-based fluorescence approach for the convenient and cost-effective measurement of amikacin in pharmaceutical formulations. In comparison with previously published approaches, the suggested method allowed for quick analysis of a high number of samples in a short amount of time (96 samples in 125 sec), resulting in an average duration of analysis of 1.3 sec per sample.     

The comet assay: a method to measure DNA damage in individual cells

We present a procedure for the comet assay, a gel electrophoresis-based method that can be used to measure DNA damage in individual eukaryotic cells. It is versatile, relatively simple to perform and sensitive. Although most investigations make use of its ability to measure DNA single-strand breaks, modifications to the method allow detection of DNA double-strand breaks, cross-links, base damage and apoptotic nuclei. The limit of sensitivity is approximately 50 strand breaks per diploid mammalian cell. DNA damage and its repair in single-cell suspensions prepared from yeast, protozoa, plants, invertebrates and mammals can also be studied using this assay. Originally developed to measure variation in DNA damage and repair capacity within a population of mammalian cells, applications of the comet assay now range from human and sentinel animal biomonitoring (e.g., DNA damage in earthworms crawling through toxic waste sites) to measurement of DNA damage in specific genomic sequences. This protocol can be completed in fewer than 24 h.     

Intrusion experiments to measure territory size: development of the method, tests through simulations, and application in the frog Allobates femoralis

Territoriality is a widespread behaviour in animals and its analysis is crucial in several areas of behavioural, ecological and evolutionary research. Commonly, territory size is assessed through territory mapping and the application of simple area estimators such as minimum convex polygons. In the present study we demonstrate that territory size can be determined adequately with an active approach through intrusion experiments, a technique that is commonly used in behavioural research in other contexts. Tests with simulated data indicate that a minimum of twelve trials needs to be performed to establish reliable orders of relative territory size. To estimate absolute territory size, detailed hull techniques are most appropriate when analyzing point patterns of intrusion experiments, while the local convex hull estimator enables the construction of internal utilization distributions based on such point patterns. Additionally we suggest a 'stretch the centre' approach to emphasize the actual process of intrusion experiments in the construction of internal utilization distributions. To demonstrate the utility of the method, we apply all findings from the simulations to data from fieldwork with the model species Allobates femoralis, a territorial aromobatid frog from the lowland rainforest of French Guiana.     

SMS seal: A new technique to measure haul-out behaviour in marine vertebrates

Many marine vertebrates, including pinnipeds, turtles and birds, spend periods of time ashore during their life cycles. Quantification of time spent ashore is important for estimating population parameters such as abundance and productivity in some species, but can prove to be a difficult task. Here we describe a novel telemetry system based on Global Systems for Mobile Communications (GSM), to provide detailed information on the haul-out behaviour of tagged animals. We tested the system on harbour seals in southwest Ireland. The GSM telemetry system proved an effective means of obtaining information on the haul-out activity of harbour seals in the study area and of providing crude movement information that was less labour intensive than VHF telemetry and provides an alternative means of data acquisition offering some advantages over satellite telemetry. The GSM tag with its internal antennae is more robust than a satellite tag. The GSM networks allow more information to be relayed, so the “cost per bit of data” is reduced. Moreover, the large global investment in GSM networks have resulted in a telemetry technology with low running costs and therefore with significantly lower costs of data acquisition via GSM relative to Argos systems. With the ever-expanding global GSM network coverage the system has significant potential applications in behavioural studies of amphibious vertebrates, such as estimating clutch frequency in sea turtles.     

Development and validation of a computed tomography-based methodology to measure carpal kinematics

Motion of the wrist bones is complicated and difficult to measure. Noninvasive measurement of carpal kinematics using medical images has become popular This technique is difficult and most investigators employ custom software. The objective of this paper is to describe a validated methodology for measuring carpal kinematics from computed tomography (CT) scans using commercial software. Four cadaveric wrists were CT imaged in neutral, full flexion, and full extension. A registration block was attached to the distal radius and used to align the data sets from each position. From the CT data, triangulated surface models of the radius, lunate, and capitate bones were generated using commercial software. The surface models from each wrist position were read into engineering design software that was used to calculate the centroid (position) and principal mass moments of inertia (orientation) of (1) the capitate and lunate relative to the fixed radius and (2) the capitate relative to the lunate. These data were used to calculate the helical axis kinematics for the motions from neutral to extension and neutral to flexion. The kinematics were plotted in three dimensions using a data visualization software package. The accuracy of the method was quantified in a separate set of experiments in which an isolated capitate bone was subjected to two different known rotation/translation motions for ten trials each. For comparison to in vivo techniques, the error in distal radius surface matching was determined using the block technique as a gold standard. The motion that the lunate and capitate underwent was half that of the overall wrist flexion-extension range of motion. Individually, the capitate relative to the lunate and the lunate relative to the radius generally flexed or extended about 30 deg, while the entire wrist (capitate relative to radius) typically flexed or extended about 60 deg. Helical axis translations were small, ranging from 0.6 mm to 1.8 mm across all motions. The accuracy of the method was found to be within 1.4 mm and 0.5 deg (95% confidence intervals). The mean error in distal radius surface matching was 2.4 mm and 1.2 deg compared to the use of a registration block. Carpal kinematics measured using the described methodology were accurate, reproducible, and similar to findings of previous investigators. The use of commercially available software should broaden the access of researchers interested in measuring carpal kinematics using medical imaging.     

Causes and consequences of animal dispersal strategies: relating individual behaviour to spatial dynamics

Knowledge of the ecological and evolutionary causes of dispersal can be crucial in understanding the behaviour of spatially structured populations, and predicting how species respond to environmental change. Despite the focus of much theoretical research, simplistic assumptions regarding the dispersal process are still made. Dispersal is usually regarded as an unconditional process although in many cases fitness gains of dispersal are dependent on environmental factors and individual state. Condition-dependent dispersal strategies will often be superior to unconditional, fixed strategies. In addition, dispersal is often collapsed into a single parameter, despite it being a process composed of three interdependent stages: emigration, inter-patch movement and immigration, each of which may display different condition dependencies. Empirical studies have investigated correlates of these stages, emigration in particular, providing evidence for the prevalence of conditional dispersal strategies. Ill-defined use of the term 'dispersal', for movement across many different spatial scales, further hinders making general conclusions and relating movement correlates to consequences at the population level. Logistical difficulties preclude a detailed study of dispersal for many species, however incorporating unrealistic dispersal assumptions in spatial population models may yield inaccurate and costly predictions. Further studies are necessary to explore the importance of incorporating specific condition-dependent dispersal strategies for evolutionary and population dynamic predictions.     

From individual behaviour to population pattern: weather-dependent foraging and breeding performance in black kites

The links between weather and animal behaviour in population processes have received relatively little attention. I studied the effect of weather conditions on foraging and breeding performance of a medium-sized raptor, the black kite, Milvus migrans. The frequency of prey capture attempts and their likelihood of success increased with temperature and declined with rainfall. Kites used flight styles involving a higher energy expenditure in less favourable weather. Nestling provisioning rates declined during rain spells. More kites hunted during periods of favourable weather and after periods with a high frequency of successful prey capture attempts by conspecifics; this result suggested that individuals may fine-tune their foraging effort to the expected foraging reward. Such compensatory behavioural adjustments may increase species resilience to climate change. The behaviourally mediated effects of weather on prey availability translated into population effects. Yearly weather conditions during the last stage of the prelaying period affected population-level productivity, probably through an effect on female body condition mediated by male provisioning capability and hunting yield. The predicted effects of climate change on kites may already be occurring, with progressively earlier laying and northward range expansion. These results confirm the need to pay greater attention to behaviourally mediated effects of climate on populations, particularly when individuals make compensatory adjustments that may enhance resilience to climate change. Copyright 2003 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.      

Sexual segregation in ungulates: individual behaviour and the missing link

Previous "explanations" of sexual segregation in ungulates establish no more than a prerequisite for habitat segregation because they do not include a model of competitive habitat selection. Here we provide one based on the ideal free distributions of mutually competing, optimally foraging, individual deer. We parameterised our model using field data collected from a population of fallow deer (Dama dama) in a Mediterranean forest. The predictions of the inter-sex competition model were in full agreement with observational data, but those of single sex distributions (conventional theory) were not. The "conventional" hypothesis, that segregation arises simply from sex differences, predicted no more than moderate (20–40%) levels of segregation, even in optimal conditions. By introducing inter-sex resource competition, the predicted segregation can generally more than double and full segregation becomes possible in some circumstances. The modelling showed segregation to be density-dependent, varying in complicated ways with season and animal density. Sensitivity analysis showed the vulnerability of the "conventional" understanding of environmental variation and uncertainty. Using our competition model we show that as diet difference increases, direct competition between the sexes declines, so that as males increasingly differ from females, segregation declines and the two sexes are more likely to be found mixed (as long as the chosen food is available to both in the same area). Conversely, small differences among male and female deer are amplified by both food depletion and inter-sex competition to give substantial levels of segregation. The theoretical framework on which our model is built strongly suggests that sexual dimorphism in the context of scramble competition may be the fundamental cause of sexual habitat-segregation among ungulates.     

The use of short-term tests to measure the preventive action of reducing agents on formation and activation of carcinogenic nitroso compounds

The effect of reducing agents on the nitrosation of methylguanidine (MG) and on the in vitro activation of dimethylnitrosamine (DMN) was examined by measuring DNA-repair synthesis (unscheduled incorporation of [3h]TdR), shifts in alkaline sucrose gradients, frequency of chromosome aberrations, and clone-forming capacity of cultured human fibroblasts. The reducing agents examined were sodium ascorbate, cysteine, cysteamine, and propyl gallate. Since the short-term bioassays used can be quantitated, it has become relatively easy to detect the inhibitory action of reducing compounds on the nitrosation reaction of MG and metabolic activation (with S-9 preparation) of the precarcinogen DMN, to measure their effective dose range, and to establish the most effective ratios between inhibitory agent and reactant. The results indicate that DNA-repair synthesis is a suitable short-term test for studying the numerous combinations and premutations between several carcinogenic or non-carcinogenic agents, and for estimating the capacity of inhibitory agents to affect formation and activation of chemical carcinogens.