A dynamic bio-economic model to simulate optimal adjustments of suckler cow farm management to production and market shocks in France

Tactical adjustments to seasonal weather conditions and beef price may generate additional income or avoid losses in French beef cattle farms. Due to the length of the suckler cow production cycle, adjustment decisions may impact not only on current production and profit but also on future farm outcomes. To better understand the consequences of shocks and subsequent production adjustments on the evolution of farm earnings and production over time, we built a dynamic recursive bio-economic farm model. Our model introduced simultaneously the possibility of adjusting herd size and herd composition, diet composition and diet energy content, as well as crop rotation, haymaking and feed stocks, taking into account both their short- and long-term consequences. An application is provided to test impacts of crop yield and beef price shocks of different intensities. Main simulated adjustments to face unfavourable weather shocks are (1) purchased feed in order to maintain animal production objectives, and (2) area of pasture harvested for haymaking. Very severe beef price shocks induce forced sales. Weather shocks affect farm net profit not only of the current year but also of the following years. Profit losses caused by unfavourable weather conditions are not compensated by gains in favourable ones and this differential is amplified when intensity of shocks rises.     

A mathematical model of the United States beef production system

Dynamic linear programming was used to model the US beef production system, to determine the cattle cycle effects on feeder cattle supplies and to select feeding options that would maximise USDA choice and prime quality grade beef production. The model represented the US as a five-region beef production system with inter-regional transportation of offspring for feeding purposes. Cow weights, offspring weaning weights and feed efficiency were different for each region, but the feeding activities were the same in each region except for region two. In region two the feeding of grain to steer and heifer offspring was not an industry practice. Dynamic properties of the model were achieved through constraints that transferred animals from year zero (initial condition) to year five using calving, cow culling, replacement heifer and death loss rates as controlling parameters. The results of model exercises that used historical parameter values indicate that there will be a significant decrease in the supply of beef at all grade levels over the next five years. They also suggest that it is more economically efficient to feed calves from the southeastern and northern parts of the USA if they are transported to the southwestern region.     

Designing crop technology for a future climate: An example using response surface methodology and the CERES-Wheat model

Future crop production will be adapted to climate change by implementing alternative management practices and developing new genotypes that are adapted to future climatic conditions. It is difficult to predict what new agronomic technologies will be necessary for crop production under future climatic conditions. The purpose of this work was to develop an approach useful in identifying crop technologies for future climatic conditions. As an example of the approach, we used response surface methodology (RSM) in connection with the CERES-Wheat model and the HADCM2 climate simulation model to identify optimal configurations of plant traits and management practices that maximize yield of winter wheat in high CO₂ environments. The simulations were conducted for three Nebraska locations differing in altitude and rainfall (Lincoln, Dickens and Alliance), which were considered representative of winter wheat growing areas in the central Great Plains. At all locations, the identified optimal winter wheat cultivar under high CO₂ conditions had a larger number of tillers, larger kernel size, fewer days to flower, grew faster and had more kernels m⁻² than the check cultivar under normal CO₂ conditions. In addition, optimal sowing dates were later and optimal plant densities were smaller than under normal conditions. We concluded that RSM used in conjunction with crop and climate simulation models was useful in understanding the complex relationship between wheat genotypes, climate and management practices.     

农用柴油机在肉牛养殖中的应用

柴油机是我国农业生产中不可或缺的动力源,农用柴油机种类繁多、经济性好、适应性强。近年来,伴随我国饮食结构调整实施“粮改饲”、“粮改畜”,以肉牛养殖等为主的畜牧养殖业得到大力发展,机械化养殖是现代化肉牛养殖的重要支撑,养殖各环节以柴油机为动力的农业机械得到了大量应用。本文以肉牛养殖为例,阐述农用柴油机在牧草生产、收获、加工、饲喂、废弃物处理环节的配套应用,分析农用柴油机发展中存在的工作稳定性较差、噪声和排放较大问题,进一步提出应用电控高压喷射等先进技术提升农用柴油机性能、做好农用柴油机与专业机具的配套适应性以及加强农用柴油机制造工艺和强化生产过程管理的发展策略。     

A predictive model for beef cattle growth and carcass composition

Due to public concerns over food quality and animal welfare, beef producers are under increasing pressure to produce a high-quality product while still maintaining economic efficiency. Hence the need for a model for the accurate prediction of growth and carcass composition of beef cattle that is flexible enough to deal with the wide range of breeds of cattle and feeding regimes, either silage only or supplemented with concentrates, encountered on UK farms. This paper describes a model that has been developed based on a substantial database of experimental observations from a series of trials carried out by the Department of Agriculture for Northern Ireland. If animal and feed costs are provided, the model can provide information on the most economic level of concentrate feeding to achieve the animal growth and quality of carcass composition required.     

A dynamic model for the simulation of cattle herd production systems: Part 1—General description and the effects of simulation techniques on model results

A computerised model to describe and predict cattle production for any herd size and time period and for a wide range of environments, was developed from a model published by Sanders & Cartwright (1979a, b).The dynamics of the model are based on the flow of energy from vegetative sources to animal products in a single-animal or cow-calf unit, so that the model is appropriate even for smallholder herds. A separate flow of numbers records the dynamically changing herd size and structure.Reproduction and mortality are linked to the nutritional and physiological status of each individual. Their occurrence is triggered stochastically to preserve the integer quality of the herd. In all other respects the model is deterministic.The simulated herd can be of any number, breed, sex and age composition. Breeds are distinguished by mature size, growth rate and milk production: they can be single, dual and/or triple purpose (dairy and/or beef and/or draught). Feeding management can be grazing, stall-feeding or a combination of the two. Routines are included which can simulate different types of management decisions and their repercussions. Functions for the quantification of the model were selected according to preset guidelines, generally following an investigation of conflicting hypotheses.There are eight different output options (tabular and graphical), representing various levels of model resolution.     

瓦努阿图肉牛养殖饲草加工设备选型及应用

结合国内饲草加工设备和瓦努阿图肉牛养殖现状,完成瓦努阿图饲草加工设备选型和适应性改进研究,调整揉草机锤片和动力配置,使其能够加工瓦努阿图当地的椰蓉、椰壳、棕榈叶和皇竹草等来饲喂肉牛,提高了瓦努阿图肉牛饲养的产能和养殖技能.     

A model to evaluate the economic merits of dry season feeding of growing/fattening cattle in the sub-humid tropics

The economic effect of increased stocking rate permitted by the introduction of dry season feedin is evaluated with reference to the growing/fatening system of beef production in the sub-humid tropics. A widely applicable model is derived which requires few input variables, all of which will be easily obtainable in a specific location. The economic break-even point in terms of feeding cost and dry season length can be determined in order to assess the value of local diets or attempt the formulation of new ones. Increae in profitability due to dry season feeding is assessed taking into account increase in stocking rate, seasonal de-stocking practices, length of dry season, growth rates, feed costs and beef price. The model is appropriate for use in developing countries and can be employed manually to determine rapidly those management options worthy of more detailed consideration.     

A timothy-beef production model for Atlantic Canada

A five-part timothy-beef deterministic simulation model was prepared to integrate information on various production processes and hence to improve the basis for management advice given by extension workers.The five parts or sub-models are: the growth of the timothy, harvesting the crop, storing it, converting the timothy and other feeds to beef and, lastly, the feeding of cattle and the disposal of manure. Costs and returns are estimated.The model structure and principal biological relationships are described in some detail. Sample outputs for three different cow-calf-feeder regimes are shown and compared.The uses, limitations and potential of the model are discussed.     

基于DeepSORT算法的肉牛多目标跟踪方法

肉牛的运动行为反映其健康状况,在实际养殖环境下如何识别肉牛并对其进行跟踪,对感知肉牛的运动行为至关重要。基于YOLO v3改进算法（LSRCEM-YOLO）,利用视频监控实现了实际养殖环境下的肉牛实时跟踪。该方法采用MobileNet v2作为目标检测骨干网络,根据肉牛分布不均、目标尺度变化较大的特点,提出通过添加长短距离语义增强模块（LSRCEM）进行多尺度融合,结合Mudeep重识别模型实现了肉牛多目标跟踪。结果表明：在目标检测方面,LSRCEM-YOLO的mAP值达到了92.3%,模型参数量仅为YOLO v3的10%,相比YOLO v3-tiny也降低了31.34%;在肉牛重识别方面,采用基于调整感受野的Mudeep模型,获得了更多的多尺度特征,其Rank-1指标达到了96.5%;多目标跟踪的多目标跟踪准确率相对于DeepSORT算法从32.3%提高到了45.2%,ID switch次数降低了69.2%。本文方法可为实际环境下的肉牛行为实时跟踪、行为感知提供技术参考。     

Exploring options for sustainable beef cattle ranching in the humid tropics: a case study for the Atlantic Zone of Costa Rica

Options are explored for sustainable, i.e. non-soil-nitrogen (N) mining, beef production in the humid tropical Atlantic Zone of Costa Rica using a modelling approach. Tools used are linear programming and a technical coefficient generator called PASTOR. Due to the combination of high rainfall, highly permeable soils and high N turnover rates, N losses are high and current natural pastures are calculated to mine soil N reserves with 40–60 kg ha⁻¹ year⁻¹. With current financial returns, there is no economic incentive for farmers to convert soil mining natural pastures to sustainable alternatives, viz. grass–legume mixtures or fertilized improved grasslands. When degradation of natural pastures over time due to soil N mining is considered in the model, it becomes economically attractive to replace these pastures with grass–legume mixtures. Sustainable beef cattle ranching is best realized by integrated intensification that raises total economic returns, i.e. use of grass–legumes or fertilized pastures, high levels of feed supplements and improved herd management techniques.     

基于ECA-YOLO v5s网络的重度遮挡肉牛目标识别方法

肉牛目标检测和数量统计是精细化、自动化、智能化肉牛养殖要解决的关键问题,受肉牛个体颜色及纹理相近和遮挡等因素的影响,现有肉牛目标检测方法实用性较差。本研究基于YOLO v5s网络与通道信息注意力模块(ECABasicBlock),提出了一种融合通道信息的改进YOLO v5s网络(ECA-YOLO v5s),在YOLO v5s模型的骨干特征提取网络部分添加了3层通道信息注意力模块。ECA-YOLO v5s网络实现了重度遮挡环境下多目标肉牛的准确识别。对养殖场监控视频分帧得到的肉牛图像采用了一种基于结构相似性的冗余图像剔除方法以保证数据集质量。数据集制作完成后经过300次迭代训练,得到模型的精确率为89.8%,召回率为76.9%,全类平均精度均值为85.3%,检测速度为76.9 f/s,模型内存占用量为24 MB。与YOLO v5s模型相比,ECA-YOLO v5s的精确率、召回率和平均精度均值分别比YOLO v5s高1.0、0.8、2.2个百分点。为了验证不同注意力机制应用于YOLO v5s的性能差异,本研究对比了CBAM(Convolutional block attention mo...     

商业化肉牛繁育大数据平台设计与关键技术

针对当前中国肉牛繁育管理水平和信息化智能化水平不高等问题,本研究借鉴国际先进肉牛养殖国家的经验,建立了适合中国的商业化肉牛繁育大数据平台。该平台主要完成肉牛种质信息资源的整合,在线自动测定肉牛关键繁育性状,全程服务支撑肉牛繁育过程,形成肉牛种质资源大数据分析决策,并实现肉牛联合育种创新模式。本文详细介绍了商业化肉牛繁育大数据软件平台开发思路,包括数据中心的实现、软件平台前端开发技术和后端开发技术等,并总结了该平台的关键技术创新和模式创新内容,包括肉牛种质资源与良种管理系谱深度挖掘技术,非接触式繁育性状自动获取评价技术,以及多源异构信息融合提供智能决策支持等,为中国肉牛种业发展提供可持续发展的信息化解决方案,以促进肉牛育种整体水平的提高。     

Greenhouse gas emissions from the Canadian beef industry

Commodity-specific estimates of the greenhouse gas (GHG) emissions from Canadian agriculture are required in order to identify the most efficient GHG mitigation measures. In this paper, the methodology from the Intergovernmental Panel on Climate Change (IPCC) for estimating bovine GHG emissions, for census years from 1981 to 2001, was applied to the Canadian beef industry. This analysis, which is based on several adaptations of IPCC methodology already done for the Canadian dairy industry, includes the concept of a beef crop complex, the land base that feeds the beef population, and the use of recommendations for livestock feed rations and fertilizer application rates to down-scale the national area totals of each crop, regardless of the use of that crop, to the feed requirements of the Canada’s beef population. It shows how high energy feeds are reducing enteric methane emissions by displacing high roughage diets. It also calculates an emissions intensity indicator based on the total weight of live beef cattle destined for market. While total GHG from Canadian beef production have increased from 25 to 32 Tg of CO₂ equiv. between 1981 and 2001, this increase was mainly driven by expansion of the Canadian cattle industry. The emission intensity indicator showed that between 1981 and 2001, the Canadian beef industry GHG emissions per kg of live animal weight produced for market decreased from 16.4 to 10.4 kg of CO₂ equiv.     

基于深度图像的多姿态肉牛体尺自动测量方法

养殖场中肉牛较为活跃,采集得到的图像数据中肉牛姿态多变,肉牛姿态端正帧较少,导致自动测量肉牛体尺困难。针对以上问题,本研究通过分析肉牛骨架特征和肉牛图像边缘轮廓特征,提出一种多姿态肉牛体尺自动测量方法。首先,利用深度相机Azure Kinect DK从正上方采集肉牛俯视深度视频数据,对视频数据进行分帧处理;其次,对原始深度图像进行预处理,将肉牛从复杂的背景中提取出来;再次,利用Zhang-Suen算法提取目标图像肉牛骨架,检测骨架交点和端点,分析肉牛头部特征,并确定头部去除点,去除图像中肉牛头部信息;最后,利用改进的U弦长曲率算法提取肉牛轮廓曲率曲线,根据曲率值确定体尺测点,将体尺测点转换到三维空间中,计算体尺参数。本研究通过分析大量深度图像数据,将图像中肉牛姿态分为左歪、右歪、姿态端正、低头和抬头五类。试验结果表明,本研究提出的基于骨架的多姿态肉牛头部去除方法在5种姿态下的头部去除成功率均高于92%;在23头肉牛不同姿态共46帧深度图像中,利用基于改进U弦长曲率的体尺测点提取方法,测得体直长测量的平均绝对误差为2.73 cm,体高测量的平均绝对误差为2.07 cm,腹宽测量的平均绝对误差为1.47 cm。研究结果可为精确测量多姿态下肉牛体尺提供支撑。     

Unravelling the rationale of `overgrazing' and stocking rates in the beef production systems of Central Brazil using a bi-criteria compromise programming model

In Central Brazil, the long-term sustainability of beef cattle systems is under threat over vast tracts of farming areas, as more than half of the 50 million hectares of sown pastures are suffering from degradation. Overgrazing practised to maintain high stocking rates is regarded as one of the main causes. High stocking rates are deliberate and crucial decisions taken by the farmers, which appear paradoxical, even irrational given the state of knowledge regarding the consequences of overgrazing. The phenomenon however appears inextricably linked with the objectives that farmers hold. In this research those objectives were elicited first and from their ranking two, `asset value of cattle (representing cattle ownership)' and `present value of economic returns', were chosen to develop an original bi-criteria Compromise Programming model to test various hypotheses postulated to explain the overgrazing behaviour. As part of the model a pasture productivity index is derived to estimate the pasture recovery cost. Different scenarios based on farmers' attitudes towards overgrazing, pasture costs and capital availability were analysed. The results of the model runs show that benefits from holding more cattle can outweigh the increased pasture recovery and maintenance costs. This result undermines the hypothesis that farmers practise overgrazing because they are unaware or uncaring about overgrazing costs. An appropriate approach to the problem of pasture degradation requires information on the economics, and its interplay with farmers' objectives, for a wide range of pasture recovery and maintenance methods. Seen within the context of farmers' objectives, some level of overgrazing appears rational. Advocacy of the simple `no overgrazing' rule is an insufficient strategy to maintain the long-term sustainability of the beef production systems in Central Brazil.     

A dynamic model for the simulation of cattle herd production systems: 2-An investigation of various factors influencing the voluntary intake of dry matter and the use of the model in their validation

Various published systems for the prediction of dry matter (DM) intake are discussed, with special emphasis on their relationship to DM digestibility. Suggestions are made for the modification of the Conrad (1966) equations and their adaptation to different types of cattle and environment.The equations were included in a dynamic simulation model to test their accuracy in predicting weight changes in growing steers under grazing conditions in Botswana and the UK. It was found that predicted weights were generally within 0.4–1.5% of measured weights and that fluctuations in the predicted liveweight curves closely followed the pattern of the observed ones, showing that the equations can provide a sound basis for the prediction of DM intake in agricultural practice in general and in livestock simulation models in particular.     

Computer assisted management decisions for beef production systems

A linear programming model was developed to determine management policy for a yearly planning horizon on a typical 1320 acre (535 ha) Southern Colorado mountain ranch. Income producing activities (selling cattle and hay and leasing land) and cost activities (buying cattle, borrowing capital, feeding supplements, purchasing fertiliser and fuel, hiring labour and leasing land) were defined for three land types through four seasons.The purpose of the modelling effort was to determine the level of each activity (cow herd size, yearling herd size and area of meadow to be harvested for hay) that resulted in maximum net return for the ranch subject to resource limitation on land, labour and capital. In addition, sensitivity and shadow price analyses revealed expansion options that would be profitable during existing economic conditions.The optimal management plan, using 3 April, 1975 prices, called for grazing 199 head of 450 lb (204 kg) steers and 52 head of 530 lb (240 kg) steers. The plan also called for purchasing and spreading 42 tons (38 MT) of nitrogen and 10 tons (9 MT) of phosphorus on Land I and for growing, harvesting and selling 742 tons (674 MT) of hay. This optimal management plan produced a net return of $27,642. In addition, the optimal plan showed that hay production began replacing beef production when the price of hay was $35·48/ton (39·08/MT) and that the maximum amount of hay was produced with the price increased to $50·00/ton ($55·00/MT).     

A critique of the Texas A&M model when used to simulate beef cattle grazing pasture

This paper describes the experiences of the authors with the Texas A&M University model when used to simulate the production of beef cattle in a grazing system. Problems associated with the lack of interaction between pasture and animals, including the monthly time interval, supplementation and an input parameter (weight at maturity), are discussed.