A general cattle production systems model. I: Structure of the model

A deterministic model for simulating beef cattle production under a wide range of management schemes and environments with cattle differing widely in genotypes for size, growth and milk production is described. In the model, genotypes are specified as production potentials, which are reached only if past and present planes of nutrition are adequate. Intake of forage and/or other feed is simulated as a function of the size and physiological status of the animals and the availability, digestibility and crude protein content of the feed. Animal performance is calculated from the nutrient intake and the animals' condition (fatness), degree of maturity and genetic potential. The model has been used for simulating beef cattle production under several widely differing sets of environmental and management conditions in Guyana, Colombia, Venezuela, Botswana, Texas and Mid-western United States and for simulating dairy-beef production systems in Colombia, Tanzania and Botswana. Results of simulations of existing conditions have coincided rather closely with actual production levels.     

Modelling dairy cattle feeding in the South-East region of Brazil

Computer modelling techniques were applied to study the structure of traditional dairy farms in the South-East region of Brazil and to help define research priorities and policies. Animal feeding is considered the principal factor affecting dairy cattle performance in the study. Knowledge of animal nutrition and feed supply from Brazilian and other literature was synthesized in two mathematical models. One model deals with the optimization of resources used in supplementary feeding for dairy cows under grazing; the other predicts dairy cow performance under a range of feeding conditions imposed by changes in the level of supplementation, stocking rate and calving date. Both models are empirical in nature. The modelling approach shows itself to be a useful means of defining research priorities and making recommendations on practical aspects of dairy cow feeding and management.     

Simulation of production systems in East Africa by use of interfaced forage and cattle models

A forage model and a cattle production model were interfaced and adapted for tropical production conditions in East Africa. The objectives of the modelling were to structure and conceptualise a complex system for better comprehension, thereby determining constraints on a traditional African grazing system. The model was designed to simulate the physical linkages between the scarce resource of forage and the outputs of cattle, meat and milk. The effects of improved management practices were examined for a traditional village livestock grazing system. Verification and validation for the baseline village herd were carried out using several different sources of data. A combination of a restricted breeding season, supplemental feeding during the dry season and a seasonal sales policy resulted in a 40% increase in net revenue to village producers above the baseline for a ten-year period.     

A simulation analysis of crop yield loss due to rust disease

The complex nature of plant disease epidemic makes them well suited to systems simulation studies. This paper reports the initial work performed by the authors in developing a model of cereal rust diseases which is sufficiently flexible to be used over a wide range of host/rust race combinations and climatic conditions. The model is intended for use in: (a) investigating the relationships between components of an epidemic; (b) studying the progress of an epidemic under specified field conditions and (c) predicting crop yield loss as a result of a given epidemic. The general structure of the model is described and then a factorial simulation experiment is discussed. This experiment illustrates the use of the model in studying the effect of four major parameters on the development of a theoretical cereal rust disease epidemic. Results from the experiment are discussed in relation to published empirical data.     

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.     

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。     

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.     

A model for estimating potential market offtake from subsistence herds

A mathematical model is presented of the regional cattle herd within a subsistence pastoral system, in a semi-arid region, where empirical data on herd production are restricted to a few basic properties under average conditions.The model was developed to estimate the potential market offtake for a region in Kwazulu (Republic of South Africa). Currently, this region is overstocked and low production levels are prevalent.The model was used to simulate various offtake strategies and it was found than an approximate threefold increase in sustainable annual revenue can be achieved while simultaneously reducing grazing pressure.     

基于SNSS-YOLO v7的肉牛行为识别方法

肉牛活动过程中所表现出的行为是肉牛健康状况的综合体现，实现肉牛行为的快速准确识别，对肉牛疾病防控、自身发育评估和发情监测等具有重要作用。基于机器视觉的行为识别技术因其无损、快速的特点，已应用在畜禽养殖行为识别中，但现有的基于机器视觉的肉牛行为识别方法通常针对单只牛或单独某个行为开展研究，且存在计算量大等问题。针对上述问题，本文提出了一种基于SNSS-YOLO v7(Slim-Neck&Separated and enhancement attention module&Simplified spatial pyramid pooling-fast-YOLO v7)的肉牛行为识别方法。首先在复杂环境下采集肉牛的爬跨、躺卧、探究、站立、运动、舔砥和互斗7种常见行为图像，构建肉牛行为数据集；其次在YOLO v7颈部采用Slim-Neck结构，以减小模型计算量与参数量；然后在头部引入分离和增强注意力模块(Separated and enhancement attention module, SEAM)增强Neck层输出后的检测效果；最后使用SimSPPF(Simplified ...     

Priorities for irrigated agriculture

The paper presents information indicating the importance of irrigated agriculture in providing much of the extra food requirements resulting from rapidly growing populations. It calls for more practical support to be given to the irrigation sub-sector so that some of the concerns about food security, competition for water and rural poverty can be alleviated. Five priority themes for support to developing countries are identified that would be particularly appropriate to utilise UK technical expertise.     

Modelling reproduction in a herd of dairy cattle

A dynamic stochastic model to simulate the reproductive process in a herd of dairy cattle has been constructed. The next event scheduling approach was utilized with four events being specified: perturition, ovulation, embryonic loss and replacement.The control variables included in the model are first breeding policy (1BDG), reproductive culling policy (RCLG), heat detection program (HDPM), breeding program (BDPM) and service sires selection program (SSPM). In addition, the model uses numerous endogenous variables such as parturition type (PRTY), oestrus behaviour (EBHV), cow's fertility (CFTY), embryonic mortality (EBLS), non-reproductive culling rate (NRCL) and others.The model was evaluated against independent experimental results. The simulated result closely approximates the average reproductive performance and variability of reproductive performance in a dairy herd.     

Application of a hydraulic model for testing management decisions at distributary level

Summary This study was conducted on the Lagar Distributary of Gugera Branch of Lower Chenab Canal, Punjab, Pakistan. A computer model MISTRAL was adopted for evaluating management options. The study showed that the model can be used as a decision support tool for prioritizing management options. The model suggests that under current physical conditions of this distributary the combination of rotation between the distributaries and along the distributary canals can improve the equity of water discharge. For example, in case of Lagar Distributary the discharge of tail outlets can be increased threefold by introducing rotation between the tail of the distributary and an offtaking minor canal. A small decrease in the discharge of the minor would result from adopting this option. A combination of rotations between this and neighboring distributaries and along the Lagar itself can increase the discharge of tail outlets up to seven times. The results of the model indicate that operational changes can improve the discharge of tail outlets to some extent, but the improvement of physical conditions of the distributary is needed to achieve equity conditions, as specified in the design.     

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。     

鸡腿菇热风干燥工艺参数优化

为了提高鸡腿菇热风干燥速率及热风干燥后产品品质,对新鲜鸡腿菇进行了热风干燥实验,研究干燥过程中热风温度X1、热风风速X2和切片厚度X3对鸡腿菇干燥速率Y1、复水比Y2和干燥产品色差Y3的影响。采用综合评分法,结合响应面分析,对多指标进行综合优化,建立指标综合值与各因子之间的回归模型,求出最佳工艺参数组合。实验结果表明:鸡腿菇热风干燥过程中各因素对鸡腿菇干燥速率及干燥后产品质量都有显著影响(P <0. 05);在热风温度55℃、热风风速1. 35m/s、切片厚度4mm的最佳工艺参数组合下进行热风干燥,鸡腿菇热风干燥速率Y1=0. 301 g/min,干燥后产品复水比Y2=3. 61,色差Y3=21. 95,综合干燥效果达到最佳,与指标综合值模型预测值相对误差低于5%。本研究可为鸡腿菇热风干燥工业化生产提供参考。     

甘蔗收获机械集成化设计开发管理模型的建立

在分析基于可视化虚拟设计技术的甘蔗收获机械设计开发总体流程的基础上，介绍了其设计开发集成建模的基本思路。详细分析了甘蔗收获机械设计开发过程管理模型的建立和实现方法，产品结构模型、产品结构配置的方法及其产品数据在PDM软件的类层次结构模型的建立，从而实现对甘蔗收获机械设计开发过程的动态调整和监控，为甘蔗收获机械集成化、系列化的设计开发提供可靠的基础和依据。     

四轴全轮驱动车辆驱动系统仿真模块的开发及性能仿真

在研究与掌握ADVISOR车辆仿真软件结构组成的基础上，开发了四轴全驱车型的动力系统仿真模块．并针对特殊的循环行驶工况，利用该模块进行了特定工况下四轴全驱车的整车性能仿真和分析，验证了在ADVISOR平台上所进行二次开发的仿真模块的正确性。     

Development of an in-field cattle finishing system for the tropics

An in-field cattle finishing system that takes advantage of the year long growing season in the tropics is described. This system exploits the interrelationships of the feed production and cattle feeding components to increase the cost and energy efficiency of the system in tropical environments. The system is based on regulated feeding of mature zones of standing corn crop to cattle. The corn crop is planted at weekly intervals year round in continual rotation. When the first planting gets to the dough-dent stage of maturity, cattle are put in the cornfield within a movable cattle pen. The feeding is regulated by moving the pen a fixed distance twice a day. This system may reduce the cost of fattening an animal from 250 to 475 kg by about 26%. To test the practicality and engineering feasibility of this program, an exploratory experiment was conducted using three steers, a 6 m × 6 m movable cattle pen and 0·23 ha land area.

It was observed that the trampling loss of corn ears by the cattle was minimal after the initial learning period of 2 to 3 weeks. The cattle also utilized about 50% to 80% of the leaves and 20% to 65% of the cornstalks. The uneaten stalks provided an excellent bedding material during wet periods. The animal weight gain performance was similar to that of feedlot cattle of the same age, weight and breed. No major health or disease problem was observed. The performance of the movable cattle pen was satisfactory during normal weather periods, but a more positive locomotion system is needed for wet conditions.     

基于扩展STIRPAT模型的湖州市能源碳排放主导 因素识别分析

基于浙江省湖州市2007年-2020年的主要能源消费数据，采用排放因子法估算主要能源碳排放量，利用扩展STIRPAT模型构建湖州市能源消费碳排放预测模型，并以人口数量、人均GDP、能源结构、单位产值能耗、农业增加值占全市生产总值比例、农业机械总动力、产业结构等为因素，分析了影响湖州市能源消费碳排放主要原因。结果发现，湖州市能源消费碳排放量总体呈“降低-升高-降低”变化趋势；碳排放模型拟合程度R2为0.812，F检验显著性小于0.01，且验证发现模型的平均相对误差为3.59%，说明该模型能较好的反应湖州市能源消费碳排放的特征；进一步分析发现，影响湖州市碳排放的主导因素为能源消费结构、单位产值能耗、农业增加值占全市生产总值的比重、农业机械总动力以及产业结构，其中上述主要因素对湖州市能源消费碳排放的影响指数分别为0.24%、-0.16%、-0.32%、-0.62%、-0.45%。     

Cattle, ethanol, and biogas: Does closing the loop make economic sense?

The recent surge in US ethanol production has led to an increase in the amount of byproduct feed available to cattle producers. The impetus behind the increase in ethanol production is US policy to increase the production and use of renewable fuels. Manure from cattle production can also be used to produce a renewable fuel: methane. By co-locating a cattle feedlot with an existing ethanol plant, there may be synergies between ethanol, methane and cattle production. Byproduct from the ethanol plant can be fed to feeder cattle, manure from the cattle used in methane production, and the methane used as an energy source in the ethanol plant. Alternatively, methane can be used to generate electricity. We investigate the economic advisability of these systems. Using cost estimates for construction and operating a feedlot and anaerobic digester for methane production, we project revenues and costs over a 20-year time period. Our findings are consistent with studies that have considered just cattle production and methane production. The investment required to build a slatted-floor feedlot and concrete anaerobic digester cannot be justified under existing economic conditions. An increase in renewable fuel/electricity subsidies of at least $0.053 per kW h or $72 per 1000 m³ of methane are required to just break even when methane is used to produce electricity or is burned for thermal energy, respectively.