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1.
Richard W.S. Fynn 《Strength and Conditioning Journal》2012,65(4):319-329
Most of the world's rangelands are subject to large spatial and temporal variation in forage quantity and quality, which can have severe consequences for the stability and profitability of livestock production. Adaptive foraging movements between functional seasonal resources can help to ameliorate the destabilizing effects on herbivore body stores of spatial and temporal variability of forage quantity and quality. Functional dry-season habitats (key resources) provide sufficient nutrients and energy to minimize reliance on body stores and are critical for maintaining population stability by buffering the effects of drought. Functional wet-season habitats dominated by short, nutritious grasses facilitate optimal intake of nutrients and energy for lactating females, for optimal calf growth rates and for building body stores. Adaptive foraging responses to high-quality focal patches induced by rainfall and disturbance further facilitate intake of nutrients and energy. In addition, focused grazing impact in high-quality patches helps to prevent grassland maturing and losing quality. In this regard, the design of many rotational grazing systems is conceptually flawed because of their inflexible movement of livestock that does not allow adaptation to spatial and temporal variability in forage quantity and quality or sufficient duration of stay in paddocks for livestock to benefit from self facilitation of grazing. Similarly the fixed intraseasonal resting periods of most rotational grazing systems might not coincide with the key pulses of nitrogen mineralization and rainfall in the growing season, which can reduce their efficiency in providing a functional recovery period for grazed grasses. This might explain why complex rotational grazing systems on average have not out-performed continuous grazing systems. It follows, therefore, that ranchers need to adopt flexible grazing management practices that allow adaptation to spatial and temporal variability in forage quantity and quality, allow facilitation of grazing (season-long grazing), and allow more effective recovery periods (season-long resting). 相似文献
2.
南方地区水热条件好,草地资源丰富且放牧家畜种类和数量较多,为充分利用当地草地资源,促进草畜平衡,本试验研究了我国西南地区人工草地不同牧压下山羊放牧行为的变化。试验采用野外群体观察法对2种牧压(重牧H和轻牧L)下山羊放牧行为及其参数进行观测记录。结果表明,2种牧压下放牧山羊采食时间都极显著(P<0.01)大于其他行为时间;鸭茅、黑麦草、白三叶的采食时间分别占总采食时间的29.2%,29.0%,25.4%,3种牧草的采食时间之和极显著(P<0.01)大于杂草的采食时间,但3种牧草之间无显著差异(P>0.05);随牧压增加与时间推移,山羊采食速度逐渐降低,但差异不显著(P>0.05);山羊采食速度与口食量呈现负相关的关系。本研究表明,放牧载畜量作为草地管理手段之一,可用来调控草地组成,增加家畜有效采食量,提高山羊放牧系统的经济效益与当地农民收入。 相似文献
3.
Emilio A. Laca 《Strength and Conditioning Journal》2009,62(5):407-417
Novel concepts and tools to promote progress in grazing science and management need to incorporate heterogeneity and nonlinear scaling of spatially and temporally distributed ecological interactions such as diet selection, defoliation, and plant growth. Traditional grazing management factors are number of animals, species and category of animals, spatial distribution of forage demand, and temporal distribution of forage demand. These traditional methods have been based on a paradigm that is static, assumes equilibrium conditions, and does not consider scaling issues, neither in time nor in space. Three related issues that can contribute to the progress in the understanding and management of grazing systems are spatial heterogeneity, event-driven dynamics, and scaling effects. Spatial heterogeneity of species and defoliation determine pasture stability by modulating competition and response to heterogeneous defoliation. When pasture species are well mixed, livestock are less able to select their preferred diet. When species are separated into larger and more easily identifiable patches, the selected diet approaches the preferred one. Simultaneously, patchiness in pasture components and redistribution of nutrients by grazing can lend global compositional stability to grass–clover pastures. Grazing at high animal density can be studied using the paradigm of event-driven dynamics. Several mechanisms suggest that grazing systems should have allometric spatial and temporal scaling in addition to the well-recognized allometric scaling of food requirements with body mass. Grazing system performance should scale allometrically with pasture size because both resource distribution and animal movements frequently have fractal properties. As pasture size increases, fewer hierarchical levels of grazing behavior are constrained, and the new spatial patterns introduce nonlinearity in the response to pasture size. Operant conditioning of foraging behavior, conditioned aversions, plant spatial pattern, pasture size and shape, timing and duration of grazing periods, and number of animals are discussed as precision tools to manage grazing systems. 相似文献
4.
为探究放牧方式对青藏高原高寒草地家畜的采食量和植物补偿生长的影响,本试验在环青海湖流域高寒草地设置放牧方式（牦牛单独放牧、藏羊单独放牧、牦牛和藏羊1：2混牧、牦牛和藏羊1：4混牧、牦牛和藏羊1：6混牧）控制试验,以期确定草地的承载力,并为制定合理的草地管理措施提供依据。试验结果表明：在群落水平上,家畜的采食量在藏羊（Ovis aries）单独放牧以及牦牛（Bos grunniens）与藏羊1：2混牧方式下,显著高于其他方式（P<0.05）;在功能群水平上,藏羊单独放牧与牦牛和藏羊1：2混牧这2种放牧方式下家畜对豆科植物的采食量较高;藏羊单独放牧与牦牛和藏羊1：2混牧植物的补偿生长能力显著高于其他放牧方式（P<0.05）。研究表明：藏羊单独放牧时,其采食量最高;牦牛和藏羊1：2混牧的放牧方式对植物补偿性生长的促进作用最明显。因此,从放牧家畜采食量与植物补偿生长两方面考虑,在青藏高原高寒草地藏羊单独放牧与牦牛和藏羊1：2混牧的放牧方式较为合理。 相似文献
5.
Until recently, the nutritional fate of the grazing animal has been largely ignored by both animal and range scientists despite the economic dependence of the extensive livestock industry on nutrition from grass. Of the three factors that can be manipulated to improve profit gross margin per animal, is one that is directly affected by nutrition and, hence, grazing management. The relationship between economics and grazing management may be summarized as: Gross margin = f(Animal Performance); Animal Performance = f(nutrition); Nutrition = f(grazing). Economical beef production must consider the needs of the animal and the forage plant at the same time. The health of the sward must be maintained while improving individual animal performance and simultaneously increasing stocking rate. Generally, plants that have been defoliated require a period of recovery before again being grazed. A sward is kept in a vigorous state by preventing repetitive defoliation at the one extreme, and avoiding excessive shading (mature growth) of photosynthetic material at the other. This state is best achieved where livestock grazing is controlled. For any individual paddock, periods of grazing are followed by periods that allow adequate physiologic recovery of the plants. A grazing regimen that keeps the plant in a healthy state is fortuitously also well suited to the nutritional requirements of the animal. Animals on overgrazed pastures are likely to suffer from inadequate feed intake because of deficiencies in feed quantity. Conversely, on over-rested pastures, intake deficiency results from paucity in feed quality. On most unmanaged ranges, overgrazed and over-rested plants are likely to be found side by side. By controlling duration of the rest period as well as duration of the grazing period through pasture subdivision, requirements of both the plant and the animal can be met. With artificially high economic demands placed on animal production, some form of supplementation is required in most modern livestock situations. Whereas energy is frequently the nutrient limiting production it is seldom economically feasible to supplement the grazing animal directly with energy. Protein supplementation to increase forage intake, and thus indirectly energy intake, has become standard practice in many grazing situations. When there is adequate forage with a low crude protein content (less than or equal to 7%), microbially degradable protein is the preferred choice. However, when the animals are in an energy deficient state, either through a shortage of available forage or because their requirements exceed energy intake levels, by-pass protein is required. 相似文献
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7.
Recently, there has been a renewed interest and an increase in published research on equine grazing and pasture management. The objectives of this paper are to review equine grazing research methodologies with an aim to encourage standardized research procedures. This review highlights standard methods used in equine pasture-related research, including use of climate data and soil type; seed bed preparation and grazing management; determining forage nutritive value; defining forage maturity; tracking horse health parameters; evaluating different grazing systems; and future technologies. This review covers in-depth discussions on determining forage biomass yield, forage populations, ground cover, persistence, forage intake, and grazing behavior. Specifically, mechanical harvesting, hand clipping, rising plate meter, and falling plate meter are all methods used to determine forage biomass yield. Frequency grid, point sampling, visual assessment, Natural Resources Conservation Service pasture condition score, and the double Dominant, Abundant, Frequent, Occasional, Rare (DAFOR) scale can be used to track forage populations, ground cover, and persistence of pasture species. Three primary methods have been used when estimating horse forage intake including the difference between pre- and postgrazing herbage mass, the difference in pre- and postgrazing bodyweight, and use of digestibility and fecal output markers. Equine grazing behavior has been described by investigating preference, pre- and post-sward height, and bite and mastication rate. Awareness of key methodologies should encourage movement toward research protocol standardization that will allow for scientific comparisons and application of pasture-related research results across the horse industry. 相似文献
8.
草地划区轮牧饲养原则及设计 总被引：2，自引：0，他引：2
为了推进北方草地可持续集约放牧饲养管理,促进完善划区轮牧实验设计及目的,本文总结了放牧国际划区轮牧的10条原则:单位时间的产草量确定载畜率,拔节期指示春季放牧开始时间,开始恢复再生的时间决定放牧时间天数,放牧间隔日数决定放牧频次,计算确定区块数及区块面积,满足牲畜采食行为,充分利用饲草质量和营养,保证牲畜饮水充足,环境友好、易执行、可操作、有弹性。在此基础上,设计了1个划区轮牧实践参考方案,并论述了划区轮牧目标及管理评价标准,讨论了1条北方草地可持续集约养羊畜牧业的发展途径。 相似文献
9.
划区轮牧与草地可持续性利用的研究进展 总被引：1，自引：0，他引：1
划区轮牧是一种充分利用饲草生长旺季而进行的集约、区块式放牧管理系统。本文总结了近年来国内外轮牧制度的发展现状,概括了划区轮牧的优势包括:提高草地生态系统的功能性、草地生产力;降低草食动物肠胃线虫感染率;分析了其与传统连续放牧相比所具有的局限性。进一步从放牧类型的延展、放牧策略的改进、人为因素的投入、生态模型研究等多角度综合考究,提出综合协调生物因素与环境、平衡生态与经济以及优化牧企合作现状的轮牧策略,以期为轮牧对于生态恢复和草地可持续性利用的生产实践应用提供科学依据和优化管理的决策参考。 相似文献
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11.
在半农半牧地区,草原资源家庭责任承包制的实施使土地被过分细分到户,导致草地的破碎化。研究表明:强化草原管理有利于以草定畜,严格控制牲畜饲养量,草地超载及代牧现象减少;畜种改良使得传统的草原放牧向半放牧半舍饲过渡,大牲畜的饲养量出现大幅度减少;草地破碎化使得草地退化以定居点和水源为中心,沿着牧道呈一定的梯度形成辐射状的区域性草地退化趋势。通过草地的联户承包,共同经营管理,促进了草畜平衡制度的顺利实施,一定程度上解决了草畜矛盾,减缓了草原生态恶化的趋势。 相似文献
12.
Daniels MJ Lees JD Hutchings MR Greig A 《Veterinary journal (London, England : 1997)》2003,165(3):1-257
Grazing herbivores avoid grass swards contaminated with faeces as the ingestion of faeces is a common route of micro- and macro-parasite transmission. The recent novel finding that herbivores do not avoid grass swards contaminated with rabbit faeces suggests that disease risk posed to herbivores by rabbits is determined by rabbit ranging and excretory behaviour. Using as a case study rabbits and the risk Mycobacterium avium sub-species paratuberculosis (M. a. paratuberculosis) poses to cattle, the interaction between rabbits and grazing pasture was studied on an infected farm in the east of Scotland in spring and autumn 2000. Radio telemetry, burrow surveys and faecal pellet count data were collected on two areas (Areas 1 and 2) of the farm with different habitat mosaics, to study the potential effects of season and habitat on the spatial distribution of rabbits faeces and thus disease in the environment. Twenty one rabbits were radio tracked and a total of 902 fixes collected. Mean home range sizes (100% minimum convex polygons) were between 2.0 and 7.1 ha per rabbit per season. Home ranges were significantly larger in spring, and in Area 1 which had more moor and woodland and less rough pasture. Rabbits used rough pasture most in Area 1 and gorse scrub in Area 2. In both areas, significantly more burrows were located in gorse scrub than in any other habitat. Most faecal pellets were deposited on the moorland habitat of Area 2 in autumn. In habitats to which grazing livestock had access, the mean rate of faecal deposition was 8571 pellets per ha per day. The greatest risk of disease transmission occurred in habitats of poor grazing quality (e.g., gorse scrub) which were used by rabbits for burrowing and thus contained high concentrations of faeces. The findings of the study are discussed in relation to management practices aimed at reducing disease risk to livestock, including the fencing of scrub and the reduction of rabbit population size to prevent expansion of rabbit burrows from scrub into grazing pastures. 相似文献
13.
《Strength and Conditioning Journal》2007,60(4):369-377
While the significant ecosystem damage caused by invasive weeds has been well documented, the economic consequences of specific invasive weed species are poorly understood. Yellow starthistle (Centaurea solstitialis L., hereafter YST) is the most widespread noncrop weed in California, resulting in serious damage to forage on natural range and improved pasture. A survey was administered to California cattle ranchers to investigate YST infestation rates, loss of forage quantity and value, and control or eradication efforts. The results were used to estimate countywide losses and costs for 3 focus counties, as well as statewide losses/costs, due to YST in California. Total losses of livestock forage value due to YST on private land for the state of California are estimated at $7.65 million per year, with ranchers' out-of-pocket expenditures on YST control amounting to $9.45 million per year. Together, these amount to the equivalent of 6%–7% of the total annual harvested pasture value for the state. Therefore, while the impacts are relatively small within the statewide total agricultural production system, losses and costs due to YST infestation do constrain California's livestock grazing sector. 相似文献
14.
An experiment was carried out at Alemaya University in Ethiopia to investigate the effect of night kraaling on the dry matter
intake (DMI), live weight gain (LWG) and foraging behaviour of Ogaden cattle. Three groups of four animals were given either
7 h access to pasture per day, simulating traditional grazing (TG) practice; extended grazing (EG) access for 11 h per day;
or traditional grazing access plus a nocturnal forage supplement (TF). Live weight gain, DMI and foraging behaviour were measured
during the late dry season (EP1) and the wet season (EP2). None of the treatments had any significant effect on either DMI
or LWG during EP1 or EP2. Extending pasture access time from 7 h to 11 h did not significantly increase the amount time spent
grazing, but grazing intensity was significantly (p < 0.05) reduced during the non-common grazing hours. Step rate was significantly lower (p < 0.01) during EP2 than during EP1 and bites per step were significantly higher (p < 0.001) during EP2 than EP1, indicating that animals had to travel a shorter distance before selecting material to eat during
the wet season (EP2). Providing supplementary forage (TF) had no significant effect on any measured parameter. In this study
neither of the two low-cost methods (EG and TF) of improving access to forage had any beneficial effect on cattle productivity.
It is concluded that, under the prevailing conditions, the traditional grazing practices of this part of Ethiopia do provide
sufficient pasture access time to achieve daily voluntary food intake. 相似文献
15.
云贵高原山区草地生物改良技术研究 总被引：10，自引：2，他引：8
对20年来在云贵高原山区进行的难利用草地改良技术进行了总结.划区围栏是控制家畜放牧和草地管理的基础,可将载畜量从3.5个羊单位/hm2提高到7.5个羊单位/hm2; 免耕补播要先用畜群(牛群效果最好)清除天然植被,补播白三叶Trifolium repens等豆科牧草,待其成苗后再补播鸭茅Dactylis glomerata 等禾本科牧草效果明显;施肥以磷肥为主,补播初期施钙镁磷肥750 kg/hm2, 第3年转为维持施肥375kg/hm2,草地生产力最高;轮牧与定牧结合,羊群与牛群顺序放牧时,草地和家畜的生产性能俱佳.合理地、综合地运用这些技术可提高山区草地的综合效益,对山区草地畜牧业的可持续发展发挥促进作用. 相似文献
16.
西藏高寒草地畜牧业的意义、问题与发展建议 总被引：20，自引：8，他引：12
概述了西藏高寒草地畜牧业在经济发展和国家生态安全等方面的重大意义；阐述了目前草地家畜两退化草原环境压力进一步加深，草地畜牧业经营管理水平较低生产和生态效益不高，因草地使用权不落实而加剧草地退化等问题；提出了今后草地畜牧业发展中特别需要解决的几个问题，如：全面落实草地使用权，加强对天然草地的管理与合理利用，加强人工草地建设，提高抗灾保畜能力，搞好退耕还草，大力发展营养体农业和季节畜牧业，采取有效措施，防治有毒有害植物与鼠类危害，加强对特色草产业的开发并促进其向产业化发展，提高草业发展的科技水平与从业者素质，以及对今后草业发展项目的建议。 相似文献
17.
优化草原生态脆弱期的家畜生产方式 总被引：2，自引：0，他引：2
我国大多数的草原区,天然植被放牧是家畜生产的主要方式.而天然草原在牧草的某些物候生长期对放牧是非常敏感的,尤其是在早春牧草返青后至3叶期这一阶段,放牧会使植物生长缓慢,整个生长季的牧草产量都减少.这段时期又正值幼畜断奶高峰,家畜对营养的需求急剧增加,草原的承载能力面临着更大的挑战.因此,根据植被在此时期对放牧的反应把这个阶段称为草原生态脆弱期.生态脆弱期的家畜生产方式应与牧草物候生长阶段同步,这样才能在满足牧草的生物需要的同时,获得更高的牧草产量以及家畜后续生产性能.本研究探讨了在早春草原生态脆弱期内可供选择的家畜生产方式:人工草地放牧,天然草地轮牧补饲,舍饲育肥以及限制饲养等. 相似文献
18.
The effect of forward (F) and lateral (L) creep grazing, as two possible management alternatives of intensive production systems, on the gastro-intestinal nematode epidemiology of ewes and lambs was studied. Two groups of Romanov x Rasa Aragonesa ewes rearing twins and maintained on an autumn-contaminated pasture at a mean stocking density of 35 ewes ha-1, were used. Measurements were made of the population of infective larvae on the pasture, level of serum pepsinogen, worm eggs in faeces of ewes and lambs, and lambs' growth rate. In addition, post-mortem worm counts from 'indicator' lambs were used to establish the level of infection at each rotational grazing cycle. Two different waves of nematode infection were identified. In both treatments, the over-wintering larvae were responsible for the first outbreak of parasitism which was particularly important for lambs on Treatment F. The second wave of infection apparently came up with several overlapped L3 generations and had different effects on the animals of each group. While early pasture contamination was suffered by the lambs of Treatment F, lambs on Treatment L were not seriously affected until the end of the third grazing cycle (end of May). The different grazing behaviour of lambs in both treatments appeared to be related to the outbreak of parasitism in lambs. The general pattern of liveweight gains was similar for both groups of animals. However, during the first 90 days on pasture lamb growth rate under Treatment L (193 g day-1) was significantly higher than that under Treatment F (164 g day-1). The serum pepsinogen values, worm burdens and liveweight gains indicate that under intensive systems where lateral creep grazing is allowed for lambs, the level of parasite infection is maintained within acceptable limits for the first 90 days on pasture with lambs' growth rate close to their potential. However, the parasitic consequences of grazing under a forward creeping system indicate that anthelmintic drenchings should be used at lambing and at 3-week intervals thereafter during the first 42 days on pasture, after which the risk of contamination from the over-wintering population is over. 相似文献
19.
农田草地系统耦合生产分析 总被引：14，自引：3，他引：11
国家科技部对未来15年畜牧业发展技术提出战略政策。指出要加大草原保护力度，合理开发1333．3万hm^2南方草山草坡及4000万hm^2农牧交错带。据此，农田草地系统耦合将成为我国家庭承包经营制农业的主要生产方式，尤其是农牧交错带和我国南方地区。分析农田草地系统耦合生产模式，管理核心是减少农田和草地系统营养物质的外流损失。生产的关键技术有草田轮作技术，农田作物秸秆再利用技术，家畜宿营技术和全日制放牧技术。 相似文献
20.
Christopher L. Crawford Zoe M. Volenec Martin Sisanya Robert Kibet Daniel I. Rubenstein 《Strength and Conditioning Journal》2019,72(1):204-209
Rangelands and the wildlife and livestock they support are critical to human livelihoods, but rangeland ecosystems increasingly suffer from overgrazing and degradation. Planned grazing, a strategy that commonly involves time-controlled rotations of high-density (bunched) groups of cattle across a pasture, is marketed as a method to enhance rangeland health and lessen livestock impacts. However, the behavioral mechanisms underlying any potential rangeland improvements resulting from rotational, high-density planned grazing have rarely been examined. To investigate these mechanisms, we compared planned grazing with conventional continuous grazing management in a savanna ecosystem in Kenya. We surveyed cattle grazing behavior, measured changes in vegetation characteristics through surveys conducted before and after cattle grazing, and measured native ungulate abundance following grazing using camera traps. Stocking rates were held constant across treatments, resulting in a commensurate decline in total foliar hits per pin (a proxy for vegetative biomass) across treatments. Planned grazing management altered cattle behavior and reduced grazing selectivity by restricting movements, causing cattle to walk more slowly while grazing and to take more bites per step. Vegetation survey results supported this finding: cattle in the planned grazing treatment ate significantly more Pennisetum grasses (typically avoided because of their unpalatability), creating the opportunity for regrowth of more palatable species after seasonal rains. We also documented significantly higher zebra presence in planned grazing plots after cattle grazing, likely due to increased relative abundance of more palatable grass species. This investigation of grazing behavior, and specifically decreased grazing selectivity as a mechanism underpinning the benefits of planned grazing, shows that when conducted at appropriate stocking densities, planned grazing has the potential to help mitigate rangeland degradation and improve rangeland sustainability for both livestock and wildlife in pastoral African savanna ecosystems. 相似文献