Movement patterns of armado, Pterodoras granulosus, in the Paraná River Basin

Abstract –  We studied the migratory behaviour of armado, Pterodoras granulosus , in the Paraná River Basin of Brazil, Paraguay and Argentina, during 1997–2005. This species invaded the Upper Paraná River after upstream dispersal was facilitated when Itaipu Reservoir inundated a natural barrier. Fish were tagged ( N  = 8051) in the mainstems of the Yacyreta and Itaipu reservoirs, bays of major tributaries, the Paraná River floodplain above Itaipu Reservoir, and below dams. In all, 420 fish were recaptured of which 61% moved away from the release area. Fish moved a maximum of 215 km (mean 42), and at a maximum rate of 9.4 km·day⁻¹ (mean 0.6). Of the 256 armados that moved away from the release site, 145 moved upstream towards unimpounded stretches of the Paraná River and 111 moved downstream into the reservoir and bays of its tributaries (maximum 150 km). Based on the observed migratory movements, we suspect that most of the reproductive output originates in tributaries to the reservoirs. The ability of this species to expand its range presents a conundrum by pitting fishery management interests against conservation needs. Maintenance of the important armado fisheries depends on the ability of the species to migrate freely to use spawning and nursery areas in reservoir tributaries and floodplains. However, its ability to migrate long distances can allow this non-native species the opportunity to invade most of the Upper Paraná River.     

Substrate choice of territorial male Topeka shiners (Notropis topeka) in the absence of sunfish (Lepomis sp.)

Abstract –  Topeka shiners ( Notropis topeka ), an endangered minnow species, typically spawn on or around breeding Lepomis sunfish (Centrarchidae) nests. Why spawning Topeka shiners are attracted to these nests is unclear, but having the nesting sunfish provide shiner eggs with improved aeration, a lessening of siltation, and protection from egg predators are possibilities. We tested the substrate utilisation of Topeka shiners in outdoor tanks in the absence of sunfish to determine the shiner's fundamental choice. Shiners were provided with substrate patches of cleaned sand, small gravel, large gravel, and small cobble, and the bare floor of the tank. The substrate above which a male shiner established his territory was used as evidence of choice. A statistically significant choice for sand substrates was demonstrated. This fundamental choice might influence which sunfish nests Topeka shiners use, given that nest substrate characteristics differ both between sunfish species and within species by spawning site location.     

Effects of yard weaning and training on the behavioural adaptation of cattle to a feedlot

Two experiments were conducted to determine the effect of weaning in small yards, with or without a feed bunk training procedure, on the subsequent behaviour and performance of Bos taurus steers in a feedlot. A reduction in the incidence of bovine respiratory disease (BRD) was the primary objective. In each experiment, about 200 male beef calves (Angus × Hereford and Hereford) were separated from their mothers at 7–9 months of age and allocated to one of three matched weaning treatment groups. The treatments were (1) yard weaning with hay or silage, (2) yard weaning with hay or silage plus a novel handling procedure to train the animals to be able to find a grain ration in a trough, and (3) paddock weaning without supplement or handling according to common industry practice in southeastern Australia. Paddock weaning is the practice of abrupt separation of cows and calves followed by return to separate pasture paddocks, whereas yard weaning involves abrupt separation but the calves remain in the yards for several days. Experimental vaccines against the major BRD pathogens were given to half of each group 1–2 months prior to entry into a commercial feedlot. The yard weaned and yard trained cattle had a significantly greater weight gain in the first month and over the 90-day feeding period than the paddock weaned control groups. There was no difference between the groups in pre-feedlot weight gain. The yard trained groups showed greater feeding activity during the first few days in the feedlot, but were not significantly different in weight gain from yard weaned. The vaccination treatment also significantly improved the weight gain in the first month and over 80 days. The combination of yard weaning and vaccination produced the highest weight gains overall. There was consistently less morbidity in the yard weaned groups compared to paddock weaned controls. The morbidity in yard trained groups was intermediate between these two. Weaning in small yards and the appropriate use of effective BRD vaccines 1–2 months before feedlot entry are recommended for B. taurus feeder steers in southeastern Australia to minimise sickness and improve productivity in the feedlot. Associated benefits are reduced risks of antibiotic residues and of animal welfare problems.     

中国电力工业的SCP范式分析

电力工业是国民经济发展中最重要的基础能源产业，是世界各国经济发展战略中的优先发展重点。作为一种先进的生产力和基础产业，电力行业对促进国民经济的发展和社会进步起到重要作用。文中运用哈佛学派的贝恩的SCP分析理论框架对我国的电力业的市场结构、市场行为和市场绩效及三者的关系进行分析．其基本分析程序是按市场结构（Structure）市场行为（Conduct）-市场绩效（Performance）展开的，旨在描述产业组织现状，发现问题并提出相应的措施。     

A review of oestrus suppression techniques in mares

Many fillies and mares are accused of behaving badly by their owners or trainers, and their reproductive hormones and ovaries are commonly blamed for this. Overt oestrus behaviour, however natural, is undesirable when a horse is being ridden, trained and competed. More subtle behaviours may be attributed to the reproductive cycle and presented as the cause of poor performance in the elite competition mare. Sometimes behaviours are complex, perhaps at odds with what one expects for normal reproductive behaviour and in many cases may not be associated with the reproductive cycle at all, rather associated with pain of musculoskeletal or soft tissue origin. The situation represents a diagnostic dilemma to positively associate undesirable behaviours with the ovarian hormones or ovarian pain, before an attempt can be made to modify the behaviour through the suppression of oestrus. This article will review the reasons for presentation, the behavioural patterns of the reproductive cycle and the diagnosis of reproductive behavioural problems. The range of techniques for oestrus suppression will be reviewed along with their clinical application and any known current regulatory issues associated with their use.     

Measuring the productivity and physical workload of brushcutters within the context of a production-based pay system

Forestry occupations are known to be physically demanding, and workers are often paid on a piece rate basis. This pay system is largely used in silvicultural treatments such as plantation and vegetation management. An ill adjusted piece rate system may induce workforce recruitment difficulties or increase accident rates and work related illnesses. A study combining work measurement, ergonomics and economics was undertaken to better understand the factors influencing a worker's workload. Mathematical relations between site factors, worker's production and heart rate variation during work have been examined based on time and motion studies of 38 brushsaw operators performing regeneration release (cleaning) in northern forests. Results show that a piece rate pay system that considers only the area treated without taking into account site factors may lead workers to behave in ways that may compromise their health and safety. The use of a pay system that integrates the influence of site factors on work performance is therefore suggested.     

白藤花粉采集时间及萌发条件的初步研究

对白藤开花习性、花粉采集时间及萌发条件进行了初步研究,结果表明：在白藤开花盛期,日开花高峰期集中在早晨4：00～8：00,其中6：00开放的花朵占当日开花总数的62．36％,其他时段开花量极少;上午8：30～11：30收集的花粉萌发力最强;在25％蔗糖液体培养基中和35℃下培养6h,花粉萌发与生长效果最佳。     

Characterization of an intravenous lipopolysaccharide inflammation model in calves with respect to the acute-phase response

Our objective was to develop a lipopolysaccharide (LPS) inflammation model in calves to evaluate the acute-phase response with respect to the release of pro-inflammatory cytokines and acute-phase proteins, fever development and sickness behaviour. Fourteen 4-week-old male Holstein Friesian calves were included and randomly assigned to a negative control group (n = 3) and an LPS-challenged group (n = 11). The latter received an intravenous bolus injection of 0.5 μg of LPS/kg body weight. Blood collection and clinical scoring were performed at 0, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 5, 6, 8, 12, 18, 24, 28, 32, 48, 54 and 72 h post LPS administration (p.a.). In the LPS group, the following clinical signs were observed successively: tachypnoea (on average 18 min p.a.), decubitus (29 min p.a.), general depression (1.75 h p.a.), fever (5 h p.a.) and tachycardia (5 h p.a.). Subsequent to the recovery from respiratory distress, general depression was prominent, which deteriorated when fever increased. One animal did not survive LPS administration, whereas the other animals recovered on average within 6.1 h p.a. Moreover, the challenge significantly increased plasma concentrations of tumour necrosis factor-α, interleukin 6, serum amyloid A and haptoglobin, with peaking levels at 1, 3.5, 24 and 18 h p.a., respectively. The present LPS model was practical and reproducible, caused obvious clinical signs related to endotoxemia and a marked change in the studied inflammatory mediators, making it a suitable model to study the immunomodulatory properties of drugs in future research.