草地家畜放牧系统草畜平衡调控技术研究

划区轮牧是提高草地家畜系统产出和实现草地畜牧业可持续发展的最佳放牧制度.放牧管理的方针是把草层高度(草地牧草生物量)保持在最利于草地生长、草地质量和家畜采食的范围内.饲料计划依据不同的时期和管理层次分为饲料概算、饲料预算和放牧计划三个水平.饲料供给由草地牧草生长速度、草地生物量和补饲确定,而饲料需求由牧场家畜数量及其生产指标水平决定.实行季节畜牧业的经营管理策略,使草地供给和家畜需求达到季节和全年的动态平衡.系统管理和效益的三个关键是划区围栏、畜群结构和载畜量.     

草地放牧制度及评价

本文根据近期国外有关资料和刊物发表的关于草地放牧制度评价方面的论述及研究结果,论述了连续放牧与划区轮牧两种放牧制度对草地家畜增重、牧草生长、家畜营养摄入和家畜行为的影响。认为影响草地牧草生长及家畜表现各方面的并不是放牧制度本身,而与其载畜率及采用的放牧技术手段和放牧条件有关。     

草地放牧制度及其评价

根据近期国外发表的有关资料和刊物关于草地放牧制度评价方面的论述及研究结果，对连续放牧与划区轮牧两种放牧制度对草地家畜增重，牧草生长，家畜营养摄入和家畜行为的影响进行综述，认为影响草地牧草生长及家畜表现各方面的并不同放牧制度本身，而与其载畜率及采用的放牧技术手段和放牧条件有关。     

划区轮牧与甘南牦牛结核病发病率相关性的调查分析

划区轮牧是根据草地牧草的生长和家畜对饲草的需求，将草地按计划分为若干分区，在一定时间内逐区循序轮回放牧，是一种先进的放牧制度。与自由放牧相比，可减少牧草浪费，提高载畜量，有利于改善牧草的产量和质量，可供给牲畜优质和充足的饲草和防止细菌性疾病的传播，经项目组调查分析，     

划区轮牧方案的制订

划区轮牧是一种世界畜牧业发达国家广泛应用的先进放牧管理制度,也是其他更加先进放牧方式的基础。它与自由放牧相比,其优越性表现为:①减少了牧草的浪费,节约了草地面积。在划区轮牧中,一定数量的家畜只在规定的日期内采食,对牧草的选择机会大大减少,草地利用更加均匀,一     

贵州草地划区轮牧对春季草地成分的影响

划区轮牧是科学合理利用草地的有效方法,本文从分析贵州草地资源、气候资源出发,探讨贵州省大方草地划区轮牧对春季草地成分的影响,按照划区轮牧的放牧方式,笔者在2015年在该地进行了实验.实验结果表明,经过划区轮牧,大方草地蕨类植物大量减少,中华厥降低了57.5%.其它杂草减少了34.6%,使得杂草得到了有效的控制.放牧家畜在草地上排出粪便,给草地施加天然有机肥,增加了草地土壤的有机质成分,给草地添加了养分,草地生产力得到了有效提高,改变牧草品质,增加家畜的采食量,提高轮牧小区的载畜量,家畜在采食过程中,踩踏杂草,有蹄耕作用,控制杂草生长,减少杂草和牧草竞争,为草地牧草创造良好的生长空间.放牧采食,要给人工牧草留大约是6 cm茬高度,不能过牧,使放牧草地有休养生息的条件,让被家畜践踏的草地得到有效的修复,防止草地退化,提高人工改良草地利用率.     

黑麦草—白三叶放牧地第一性生产力研究

基于对南方草地放牧条件下草地季节调查，对草地地上生物量，地下生物量，枯死体，家畜移出量，第一性生产力以及牧草生长速率与气候因子的关系进行了研究。     

高寒草地天然牧草Ca、P含量及其分布规律

高寒草地天然牧草是高原放牧家畜主要日粮来源,全年天然牧草营养的不均衡和家畜营养需要的恒定,严重制约了高寒草地畜牧业的发展。文章通过综述青海、西藏、甘肃和新疆有关高寒草地牧草营养价值的研究文献,整理综合高寒牧草Ca、P的营养成分数据,以不同牧草不同生长时期为划分单位,探究不同地域、不同生长期高寒天然牧草Ca、P含量极其分布规律,为高寒草地放牧家畜精准补饲饲养提供基础参数,通过适度补饲解决高寒草地营养供给不均衡问题。     

肃南山地放牧系统四季供需动态模型

通过分析和综合肃南山地放牧系统的四季放牧试验数据,模拟了该系统的牧草供给与家畜需求的季节动态,用模式图反映了放牧系统牧草供需平衡机理。通过分析放牧系统的时间地带性的生态要素,拟合了肃南山地放牧系统的放牧函数,并建立了北半球中纬度地区的一般方程。这些模型数量化地解释了“生物的时间地带性”理论在山地放牧系统牧草供给与家畜需求平衡中的作用,对放牧管理和畜牧业持续发展具有一定的指导作用。     

南方"黑麦草-水稻"轮作系统中可推广应用的多花黑麦草品种简介

饲草饲料是发展畜牧业的物质基础,其质量的好坏和数量的多少直接影响到畜牧业生产的发展.目前,我国草地资源因过度毁林、毁草、开荒,天然草地面积逐年减少,现有的草地也因过度放牧,草地牧草质量降低,优良牧草在草地中的比例下降,自然更新困难,草地严重超载和管理不当而严重退化,载畜能力下降.因此,南方地区草食家畜的发展,仅仅依靠天然的草山草坡是不行的.特别是在冬春季节,由于天然牧草枯竭,造成长期以来夏秋季节牲畜增膘、冬春季节牲畜掉膘的规律性变化的现象.草食家畜饲养周期长,出栏率低,制约着农民的养殖效益.     

Enhancing the profitability of pasture-based dairy production in the humid tropics through improved nutrition

Dairy production in the tropics represents a major challenge, especially when reliant on grazed forages, because of the conflicting factors of a high nutritional demand to sustain lactation on the one hand, and the relatively low quality of tropical grasses and a stressful environment, on the other. This paper focuses primarily on those tropical situations where grazed pasture is the cheapest feed resource. Effective management of the pasture as well as the animals that graze it is required in order to maximize economic viability of the farming enterprise. Feed planning helps to ensure that pasture use is maximized, either directly by grazing or, where profitable, indirectly by cutting for conservation. High rates of pasture utilization at each grazing minimize pasture senescence and decay and ensure that pasture remains in a vegetative state of the highest possible nutritional quality. Total annual feed requirements of the grazing herd must therefore be matched as closely as possible to the total annual pasture production on the farm. Stocking rate is critical in this regard, and is the single most important determinant of productivity in pastoral farming. Periods of pasture surplus or deficit will inevitably arise, but can be minimized by matching the monthly feed requirements of the herd as closely as possible to the monthly feed production on the farm. Herd requirements can be influenced, for example, through altering calving patterns and drying off dates. Even with good pasture management practices, it is highly likely that tropical pasture quality will be low for part of the year. Utilization of low-quality forages can be improved through the appropriate use of feed supplements, and the key principles are discussed. Firstly, conditions for optimum fermentative digestion in the rumen must be promoted through adequate provision of fermentable energy and nitrogen as well as essential minerals, such as phosphorus and sulfur. Further supplementation with metabolizable energy or protein, depending on what limits animal production, may be profitable. Various practical supplementation strategies for tropical forages are discussed. Finally, some suggestions for future research and development for enhancing the profitability of pasture-based dairy production in the humid tropics are made.     

Application of Lineweaver-Burk data transformation to explain animal and plant performance as a function of nutrient supply

This study evaluates the effect of dry-season concentrate supplementation on growing cattle performance grazing tropical pasture and the impact of nitrogen fertilization on the growth rate of tropical pasture (tons of dry herbage mass/ha/110 days) and on the subsequent stocking rate and cattle performance during the rainy season (kg body weight gain/ha/110 days). The animal and plant responses were curvilinear to the increasing amount of nutrient supply and followed the typical saturation kinetics of enzyme systems, a Michaelis-Menten relationship. The Lineweaver-Burk data transformation explained efficiently the animal and plant responses to the nutrient supply. This methodology consists in evaluating the linear regressions of the reciprocal of animal and plant responses as a function of the reciprocal of nutrient supply. The half maximum growth rates for plant and animal to nutrient supply were verified with the proportions from .048 to .056 of the amount needed to cause .95 of theoretical maximum responses. From the curvilinear response, it can be verified that the marginal increase in animal and plant growth rate reduces as the amount of nutrient supply increases.     

Feeding value of pastures for horses

The feeding value of fresh pasture grazed in situ is determined by animal performance or productivity and could be relatively easily established for growing and lactating horses. Despite this, there is a lack of published information on the relative feeding value of different pastures and forages grazed by horses in New Zealand and the world. In addition, for adult breeding or non-breeding and young or adult sport or performance horses, the definition of feeding value and its determination remain problematic.

Limited information suggests that the feeding value of perennial ryegrass-based pasture in New Zealand for young growing horses is high, and growth rates for Thoroughbred horses fed solely on pasture in New Zealand are similar to those reported from the Northern Hemisphere where grain-based supplements are fed in addition to pasture or other forages. Attempts to assess the ability of fresh pastures to meet the nutrient requirements of horses are hampered by problems associated with determination of feed intake by grazing horses and lack of knowledge of the digestibility and utilisation of digested nutrients, including the relative bio availability of macro- and micro-minerals in pasture. A further challenge for future research is to determine the effect of herbage allowance and grazing behaviour, including pasture species preferences, on voluntary feed intake by grazing horses.

Grazing pasture has benefits for equine health and well-being including reduced risk of some nutrition-related disorders and reduced prevalence of stereotypic behaviour. Pastured horses have greater freedom for expression of natural behaviours including social interaction and exercise. However, grazing pasture is also associated with animal health problems, particularly parasitism and diseases related to pasture-associated toxins.     

Feeding value of pastures for horses

The feeding value of fresh pasture grazed in situ is determined by animal performance or productivity and could be relatively easily established for growing and lactating horses. Despite this, there is a lack of published information on the relative feeding value of different pastures and forages grazed by horses in New Zealand and the world. In addition, for adult breeding or non-breeding and young or adult sport or performance horses, the definition of feeding value and its determination remain problematic. Limited information suggests that the feeding value of perennial ryegrass-based pasture in New Zealand for young growing horses is high, and growth rates for Thoroughbred horses fed solely on pasture in New Zealand are similar to those reported from the Northern Hemisphere where grain-based supplements are fed in addition to pasture or other forages. Attempts to assess the ability of fresh pastures to meet the nutrient requirements of horses are hampered by problems associated with determination of feed intake by grazing horses and lack of knowledge of the digestibility and utilisation of digested nutrients, including the relative bioavailability of macro- and micro-minerals in pasture. A further challenge for future research is to determine the effect of herbage allowance and grazing behaviour, including pasture species preferences, on voluntary feed intake by grazing horses. Grazing pasture has benefits for equine health and well-being including reduced risk of some nutrition-related disorders and reduced prevalence of stereotypic behaviour. Pastured horses have greater freedom for expression of natural behaviours including social interaction and exercise. However, grazing pasture is also associated with animal health problems, particularly parasitism and diseases related to pasture-associated toxins.     

Feeding value of pastures for ruminants

Perennial ryegrass is the primary forage component of ruminant diets in New Zealand. It is persistent and palatable, and immature ryegrass has a high nutritive value (NV). However, seed-head development substantially lowers its feeding value (FV) as fibre concentration increases, the rate and extent of digestibility decreases, and voluntary intake declines. Ryegrass pastures are susceptible to accumulation of endophytic and saprophytic fungi in dead material at the base of the sward, especially when mature and laxly grazed. Feeding forage legumes to ruminants grazing grass-dominant pastures will improve animal performance and lessen the reliance on a single species to meet all nutritional requirements.

The FV of forage is a function of intake and NV, measured by chemical analyses and animal feeding trials. Performance of individual animals grazing forages is usually limited by energy intake because structural fibre can slow digestion and clearance from the rumen and because of competition between individuals for available feed. The use of metabolisable energy (ME) content of forage to signify FV can give a reasonable indication of animal performance, but it should be used in conjunction with chemical analyses to improve the accuracy of predictions.

The relationship between FV, pasture production, animal performance and profitability is complex. The importance of skilled management to maintain pasture quality and optimise animal performance under inconsistent climatic conditions should not be underestimated. Acceptable animal performance with minimal veterinary intervention requires good nutrition, but the genetic potential of livestock in New Zealand cannot be met solely by grazing pasture, especially when a high utilisation of pasture is required to maintain quality and profitability.

Producers are responding to industry demands to reduce the seasonality in supply of milk and meat by changing lambing and calving dates, and extending lactation length in dairy cows. Social changes include adoption of once-daily milking in the dairy industry. Some changes have necessitated increased use of supplements and others can be met by feeding forages with a higher FV than ryegrass, all of which require an improved knowledge of feed quality. This information is available through rapid and inexpensive near infrared spectroscopy (NIRS) analysis, enabling animal nutritional needs to be balanced by appropriate nutrient supply. It is essential that producers continue to improve animal welfare, limit excessive use of fertilisers and meet the demands of overseas consumers. Good nutrition, with an increased use of legumes and other forages to complement ryegrass pastures, will enable these objectives to be achieved.     

Feeding value of pastures for ruminants

Perennial ryegrass is the primary forage component of ruminant diets in New Zealand. It is persistent and palatable, and immature ryegrass has a high nutritive value (NV). However, seedhead development substantially lowers its feeding value (FV) as fibre concentration increases, the rate and extent of digestibility decreases, and voluntary intake declines. Ryegrass pastures are susceptible to accumulation of endophytic and saprophytic fungi in dead material at the base of the sward, especially when mature and laxly grazed. Feeding forage legumes to ruminants grazing grass-dominant pastures will improve animal performance and lessen the reliance on a single species to meet all nutritional requirements. The FV of forage is a function of intake and NV, measured by chemical analyses and animal feeding trials. Performance of individual animals grazing forages is usually limited by energy intake because structural fibre can slow digestion and clearance from the rumen and because of competition between individuals for available feed. The use of metabolisable energy (ME) content of forage to signify FV can give a reasonable indication of animal performance, but it should be used in conjunction with chemical analyses to improve the accuracy of predictions. The relationship between FV, pasture production, animal performance and profitability is complex. The importance of skilled management to maintain pasture quality and optimise animal performance under inconsistent climatic conditions should not be underestimated. Acceptable animal performance with minimal veterinary intervention requires good nutrition, but the genetic potential of livestock in New Zealand cannot be met solely by grazing pasture, especially when a high utilisation of pasture is required to maintain quality and profitability. Producers are responding to industry demands to reduce the seasonality in supply of milk and meat by changing lambing and calving dates, and extending lactation length in dairy cows. Social changes include adoption of once-daily milking in the dairy industry. Some changes have necessitated increased use of supplements and others can be met by feeding forages with a higher FV than ryegrass, all of which require an improved knowledge of feed quality. This information is available through rapid and inexpensive near infrared spectroscopy (NIRS) analysis, enabling animal nutritional needs to be balanced by appropriate nutrient supply. It is essential that producers continue to improve animal welfare, limit excessive use of fertilisers and meet the demands of overseas consumers. Good nutrition, with an increased use of legumes and other forages to complement ryegrass pastures, will enable these objectives to be achieved.     

饲用小麦生产与利用研究现状及发展前景

随着生活水平的提高和食品消费结构的变化,对动物蛋白的需求迅速增长。然而,由于缺乏优质粗饲料,畜牧业的发展受到了很大的限制。饲用全株小麦产量高、营养品质好,已成为一种优质的饲料来源,因此,围绕饲用小麦的相关研究意义重大。梳理近年来国内外关于饲用小麦生产和利用的现状及发展趋势,重点概述的内容有:1)品种选育:种质创制技术、逆境分子育种和常规饲用小麦品种筛选;2)栽培管理:常规田间管理、放牧利用管理和粮饲兼用管理;3)青贮加工的影响因素:栽培管理、生育期、添加剂和其他因素;4)家畜的饲喂效果:采食量、消化率、畜产品产量和品质等。此外,总结了饲用小麦各研究领域中所存在的问题和不足。同时,对新形势下饲用小麦的研究趋势和研究重点进行了展望,以期对我国饲用小麦的生产和推广利用提供指导与参考。目前,饲用小麦的发展背景主要是粮食过剩、饲草供需矛盾和动物生产性能等问题,它在产量和营养方面表现优异,尤其在冬季饲料缺乏时,小麦具备更大的生长优势,无论是放牧还是青贮利用都较方便,这也缓解了目前的饲料危机,为畜牧业的安全发展提供了保障。但是,粮用小麦品种一般为矮秆,其全株产量受限,为更好地发挥小麦的饲用价值,培育饲用专用品种势在必行。     

Mathematical models to assess strategies for the control of gastrointestinal roundworms in cattle 1. Construction

Mathematical models were constructed to simulate the effect of Ostertagia ostertagi infections on the growth of young cattle. The equations are based on System Dynamics using the DYSMAP 2 software package in their construction. A pasture and animal growth model simulates the growth of pasture and the influences of management and climate on it; cattle feed intake and conversion into energy for maintenance and liveweight gain; the effect of the parasite burden on feed intake and utilization of energy. This model was then combined with one of the life cycle of O. ostertagi in order to determine the effect of worm burdens on animal growth rate in a range of farm conditions, such as stocking rate, grazing history of the pasture, and rainfall. By converting the resultant liveweight gain into a monetary value, an economic assessment of alternative worm control strategies can be made. In this paper the construction of the models with equations and assumptions is given in detail.     

New Approaches and Tools for Grazing Management

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.     

Mathematical models to assess strategies for the control of gastrointestinal roundworms in cattle 2. Validation

A computer model of the population biology of Ostertagia ostertagi in young cattle and the effect of the parasite on animal growth has been constructed. It was validated against results from field trials where worm populations and rate of growth of cattle treated with anthelmintics were compared to similar groups of untreated animals. A close correlation between observed and predicted values for faecal egg and pasture larval counts was seen in the cattle which had been treated with an oxfendazole pulse release bolus at turnout. Timings and peak values were less accurately predicted in the untreated cattle. Although predictions for live weight gain during the grazing season indicated that the model may be overestimating the potential growth rate of cattle, it is considered that the model provides a suitable tool for comparing the effectiveness of different worming programmes under farm conditions. The computer simulation also allowed examination of the underlying influences and interactions between parasitological factors, such as numbers of immature and adult worms, and animal and pasture factors, such as sward height, grass consumption and feed conversion, in the parasite's influence on animal performance.