The Borana pastoral system of Southern Ethiopia

This paper, based on the Joint Ethiopian Pastoral Systems Study (JEPSS) conducted from the International Livestock Centre for Africa (ILCA), describes the Borana System of Southern Ethiopia. The supply of dry-season well water in the Borana rangelands allows a semi-settled existence. However, while milking herds (warra) are kept at the settlement, dry cattle (forra) travel further afield in search of dry-season grazing. Stocking densities are reasonably close to the maximum potential except in areas not supplied by wells. Reproduction rates, and milk yields of the Boran cattle, are quite high for pastoralist herds, while mortalities are low. Sheep, goats and camels supplement production from cattle. Although milk is the staple food of the Borana, grain purchased with the proceeds of livestock sales meets over 30% of dietary energy requirements. Overall, the Borana are efficient rangeland and livestock managers, who manage to survive in a tightly constrained environment. These findings suggest that the scope for improvement is limited.     

Cattle accumulation and the commercialization of the traditional livestock industry in Botswana

The unfenced ranges of Botswana support large cattle herds, which are operated on a commercial basis, and small herds, which are managed in order to meet family subsistence needs. The distinctive herding practices and sales strategies associated with large and small herds are suited to the variable amounts of human labour, cash and saleable animals at the disposal of herd owners. If they are to operate permanently on a commercial basis, small herds must grow in size. The process of commercialization will not, therefore, alleviate overstocking on communal rangelands and the majority of small herd owners are not likely to endorse any programme of voluntary destocking.     

基于Web的奶牛场管理信息系统

介绍基于JSP+SPrvlet+Javabean模式开发的、适合中型奶牛场使用的奶牛场管理信息系统,分为牛群管理、产乳管理、牛群繁殖、统计与分析、养牛场管理及系统管理功能6个方面,可以对奶牛及奶牛场各种技术数据进行分析与综合整理,是一种实用、经济和操作简便的奶牛场信息资料管理系统.     

Evaluation of strategies for tracking climatic variation in semi-arid grazing systems

Ways of ‘tracking’ environmental fluctuations could be of value in limiting drought-induced mortality and increasing output. We examined a range of tracking policies, designed to tackle climatic variation, using a simulation model of a semi-arid grazing system. These compared annual sales designed to limit stocking rate, pre-emptive sales triggered by insufficient rainfall, and variable sales and stocking rate regimes determined by the current season's rainfall. Although the flexible stocking strategies did reduce mortality losses, compared with fixed stocking, they did not increase average annual sales. The main reasons for this are that major losses of stock are associated less with 1-year than with 2-year droughts, which are difficult to track, and that destocking can be really effective only if the productive potential of the herd can be re-established more rapidly than is possible from depleted herd resources. Tracking policies did have a considerable advantage in terms of reduced inter-annual variability of sales, which would be of economic benefit to the commercial livestock sector. For subsistence pastoralists, the traditional policies of maintaining the maximum number of breeding stock, and of hoping that most of them will survive drought, may be as close as ‘opportunistic’ management can get to dealing with drought.     

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).     

Maasai herd and flock structures in relation to livestock wealth,climate and development

Information was obtained on the structure of the herds and flocks of a sample of 41 households on the three Maasai Group Ranches in Kenya. The purpose of the survey was to contribute to an intensive study of the livestock production system, and also to assess the amount of information that could be obtained from a herd structure study on its own. Differences in herd structure were related to the livestock wealth of the household, the stage of development of the Group Ranch as well as to the variation in climate, and production alternatives.Data from more than 5100 cattle revealed that Maasai herds contained less steers in 1982 (18%) than in 1968 (22%). The proportion of mature steers had also dropped from 5% (1968) to 2% (1982), with maximum valves of 3·2% on the most developed ranch and 2% for the wealthiest stratum of households. A high percentage of females had been retained (56%) giving a herd structure characteristic of subsistence production with milk as a primary output. This structure also caters for a strong market in immature animals and gives the herd a high potential for recovery after a drought. There appeared to be a trend towards increased use of introduced bulls, notably Sahiwal on the Small East African Zebu, with increased Group Ranch Development. However, this trend was confounded by a decreasing aridity gradient with increased development.On two of the ranches for which 1968 counts were available, cattle numbers were 119% of their previous value whereas small stock were 470%. The reason appears to be that increased sedentarisation without adequate range management has resulted in a severe reduction in grasses, and their replacement by forbs. These plants are more palatable to small stock which are better able to exploit the degraded habitat.Information from more than 2730 sheep and 2300 goats revealed that poor households preferred goats and richer households, sheep. The Small East African Goat was ubiquitous, but the most developed ranch had crossed Dorper onto Maasai sheep whereas the least developed and most arid ranch had introduced Somali Blackhead sheep. The Dorper crossbred catered for a market for mutton whereas the Blackhead was primarily for home consumption of fat.The conclusion is that Group Ranch Development has not projected the Maasai into commercial beef ranching as originally planned, but their production system has not stood still. A study of herd structures was a good way of demonstrating the evolution of the system. The method was simple but was dependent for its success on fairly involved and time-consuming sampling and data collection procedures.     

Assessing the historical frequency of drought events on grazing properties in Australian rangelands

Using a simulation model of sheep and cattle grazing systems in different regions of the Australian rangelands, we tested the use of different measures and analyses for identifying an ‘exceptional circumstances’ drought event, defined as occurring once in 20 years in the long term. Over the century-long simulations, all measures (rainfall, various soil moisture measures, pasture growth, liveweight gain and an economic productivity index) identified the major drought periods in each region. However, the measures differed considerably in the identification of marginal events, because economic and biological hardship are not always synchronised. Total soil moisture seems to be the best single measure, providing it is properly calculated, but there is a strong case for considering more than one measure. Periods perceived as exceptional are also greatly affected by the choice of averaging technique, moving window, and assumptions about baseline management strategies. Hence the choice of index has implications for sustainability. We also show that revocation criteria are as important as the criteria for declaring a drought, and discuss the difficult balance between objectivity and equity.     

黄土高原不同水平年旱涝时空分布特征分析

全球气候变暖大背景下,黄土高原总体呈现暖干化趋势,未来干旱还可能会加剧。为了全面了解黄土高原旱涝时空变化特征,为黄土高原应对旱涝灾害提供决策依据,根据黄土高原及周边263个气象站的降水数据划分降水水平年,以标准化降水指数（SPI）为指标,分析了黄土高原地区不同水平年年际及年内旱涝特征。结果显示,黄土高原在丰、平、枯水年均有不同程度的干旱发生。丰水年黄土高原干旱面积占5.7%,雨涝面积占40.9%;平水年干旱面积占12.7%,雨涝面积占19.3%;枯水年干旱面积占44.4%,雨涝面积占17.9%。不同水平年的干旱区域存在差异。不同水平年内春旱较重,丰水年和平水年雨季开始后干旱逐渐缓解,枯水年雨季不能有效缓解春季以来的干旱,且秋涝明显,各水平年年内干旱的时空分布存在显著差异。不同水平年年际和年内旱涝差异大且变化频繁,为了确保黄土高原农业生产旱涝保收,应合理布设小型水利工程与田间灌溉设施。      

The ecology and management of small ruminant production systems in the sertao of Ceara,in the Northeast of Brazil

This study is part of a multidisciplinary research to describe and analyze the small-ruminant production system in the Northeast of Brazil. Twenty-seven small-ruminant producers were studied in the sertao of the state of Ceara to identify and describe land-use and animal-management schemes. No two production systems studied were exactly alike. However, 16 different management strategies were identified and structured according to ecological environment, grazing resources, crop-residue availability and farm infrastructure. Two common features are the interaction of crop and livestock production and the multispecies character of animal herds. The study compares producer's strategies for coping with the drought in regard to the herd composition, stocking rates, animal condition, supplementation and water supply in both 1980 and 1983. It was observed that farms that had cattle, sheep and goat herds performed relatively better during the drought period than farms with cattle and sheep only.     

基于信息熵大型灌区农业旱情的TOPSIS综合评价

在分析国内外农业干旱评价研究现状的基础上,提出了农业旱情综合评价的TOPSIS评价方法.选择降雨、径流、水库蓄水和地下水等影响干旱的主要因素作为评价分析的特征指标,引入信息熵来计算各评价指标的权重,建立了基于熵权的TOPSIS综合评价模型,根据理想解的欧氏距离判别旱情等级.将该模型对关中地区旱情状况进行综合评价,评价结...     

Cattle are cash generating assets for mixed smallholder farms in the Eastern Amazon

The presence of cattle in the Amazon region is controversial in terms of their ecological suitability and profitability compared with crops. Nevertheless, they are widely distributed in the study area in north-eastern Pará and, contrary to the common image of cattle on large ranches, a high proportion of them are kept on smallholder farms. To explain their presence, cattle are assumed to have benefits beyond physical production, such as complementing resource use or representing capital. To test this hypothesis, the costs and benefits of the three main agricultural activities, cattle, cassava and black pepper production, in terms of land, labour and capital productivity, were recorded in 37 small farms over a period of 15 months. To provide a longer perspective, benefits and costs of these activities were calculated for their assumed lifetime, which in the case of cattle, assumed a stable herd, derived from a deterministic herd model. The resultant values for land, labour and capital productivity of cattle were much lower than the values derived from direct observations during the study period, and were not as high as those for cassava and black pepper. Furthermore, the analysis of resource use in the farms showed that cattle production was not usually integrated with cropping activities, did not improve the use of available labour, and competed for land. Therefore, there had to be a reason for keeping cattle beyond their physical productivity. It was deduced to be their functional quality. Cattle could be disposed of quickly and easily at any time, in order to acquire large sums of cash or the equivalent in kind. The liquidity derived from keeping living stock was not matched by other agricultural activities or by the financial market. Hence, cattle turned out to be the best instrument of finance for the smallholder. Farmers were not interested in the continuous development of their herds, or sustainable production practices, and favoured low input management. Consequently, development plans relying on long-term, continuous commitments to pasture and cattle management are inappropriate. Instead, research and extension work should focus on simple, flexible and low-cost improvements to cattle keeping on crop-livestock smallholder farms, until credit programmes are available that replace the financing function of cattle.     

Using the GrassGro decision support tool to evaluate some objective criteria for the definition of exceptional drought

Some objective criteria for defining conditions of exceptional drought were evaluated using the GrassGro decision support tool. In two analyses, pasture and animal production were simulated from historical daily weather records for the last 95 years at sites in central New South Wales. The first analysis successfully discriminated between two sites 40 km apart, only one of which had received an effective fall of rain during a long dry spell. In the second analysis, production was simulated at one of these sites to identify the exceptional droughts over the 95-year period from the percentage ranking of moving averages of monthly rainfall, available green herbage and the supplementary feed required for sheep survival. Greater summer rainfall in the second half of the period meant that most of the exceptional droughts were in the first half. We suggest that a monitoring system based on shire-by-shire simulations of appropriate grazing systems, using 18-month moving averages of the weight of supplementary feed required for the survival of the animals, may be a practicable way of establishing exceptional drought circumstances.     

Replacement policy in dairy herds on farms where heifers compete with cows for grassland: Part 2-Experimentation

Replacement policy is not easy to determine on dairy farms where heifers compete with cows for grassland. Using a computer simulation model of this farm situation, two factorial experiments were conducted to evaluate quantitatively the effect of different replacement rates on profitability and herd improvement.The variables changed in herds of average health and very good health were replacement rate (0·14, 0·22, 0·30), age at first calving (36, 24 months), calving index (13, 12 months) and AI sire merit (standard, premium). Initially, the experimental herd had average health, a replacement rate of 0·22, a calving index of 13 months, calved its heifers at 36 months and had been using standard bulls for many years.After 15 years, the increase in the level of a sinking fund when the age at first calving was reduced was between three and five times greater than when premium bulls were used, calving index was reduced or herd health was improved. There was a major interaction between replacement rate and age at first calving.Yield per cow was significantly reduced (P≤0·001) by reducing the age at first calving and significantly increased when premium bulls (P≤0·001) were used or when herd health was improved (P≤0·05).Some treatments were not tested as expected due to the restraining effect of a 13-month calving interval on the availability of cows for breeding pure in a seasonally calving herd.     

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.     

基于水资源干旱指数的阿克苏绿洲干旱预警模式及其应用

阿克苏绿洲地区干旱灾害频发,为对该地区干旱灾害进行预警,建立了以水资源干旱为基础的阿克苏绿洲干旱预警模式。在阿克苏绿洲水循环特征分析的基础上,以水资源干旱指标作为绿洲干旱指数的评估指标,识别了阿克苏绿洲干旱的主要控制因子,并在阿克苏绿洲供需水关系分析的基础上,建立了其与先导性气象要素的定量关系,将其转化为具有常规观测资料的气象要素,构建了以气温为核心的干旱预警指标。结果表明,应用该预警指标对阿克苏绿洲经行干旱预警,一个月预警准确率达到了86.8%,具有较高的精度。     

Breeding for improved abiotic stress tolerance in maize adapted to southern Africa

The difficulty of choosing appropriate selection environments has restricted breeding progress for abiotic stress tolerance in highly variable target environments. Genotype-by-environment interactions in southern African maize growing environments result from factors related to maximum temperature, season rainfall, season length, within-season drought, subsoil pH and socio-economic factors that result in sub-optimal input application. In 1997, CIMMYT initiated a product-oriented breeding program targeted at improving maize for the drought-prone mid-altitudes of southern Africa. Maize varieties were selected in Zimbabwe using simultaneous selection in three types of environments, (i) recommended agronomic management/high rainfall conditions, (ii) low N stress, and (iii) managed drought. Between 2000 and 2002, 41 hybrids from this approach were compared with 42 released and pre-released hybrids produced by private seed companies in 36–65 trials across eastern and southern Africa. Average trial yields ranged from less than 1 t/ha to above 10 t/ha. Hybrids from CIMMYT's stress breeding program showed a consistent advantage over private company check hybrids at all yield levels. Selection differentials were largest between 2 and 5 t/ha and they became less significant at higher yield levels. An Eberhart–Russell stability analysis estimated a 40% yield advantage at the 1-t yield level which decreased to 2.5% at the 10-t yield level. We conclude that including selection under carefully managed high-priority abiotic stresses, including drought, in a breeding program and with adequate weighing can significantly increase maize yields in a highly variable drought-prone environment and particularly at lower yield levels.     

Improving drought tolerance in rainfed lowland rice: An example from Thailand

A large portion of the world's poor farm in rainfed systems where the water supply is unpredictable and droughts are common. In Thailand there are approximately 6.2 million ha of rain fed lowland rice, which account for 67% of the country's total rice-growing area. This rice system is often characterised by too much and too little water in the same season. Farmers’ estimates of their annual losses to drought are as high as 45% in the upper parts of the toposequence. In contrast to irrigated rice systems, gains from crop improvement of rainfed rice have been modest, in part because there has been little effort to breed and select for drought tolerance for the target rainfed environments. The crop improvement strategy being used in Thailand considers three mechanisms that influence yield in the drought prone targets: yield potential as an important mechanism for mild drought (where yield loss is less than 50%), drought escape (appropriate phenology) and drought tolerance traits of leaf water potential, sterility, flower delay and drought response index for more severe drought conditions. Genotypes are exposed to managed drought environments for selection of drought tolerant genotypes. A marker assisted selection (MAS) scheme has been developed and applied for selection of progenies in the backcrossing program. The plant breeding program uses rapid generation advance techniques that enable early yield testing in the target population of environments (TPE) through inter-station (multi-location yield testing) and on-farm trials. A farmer participatory approach has been used to identify the TPE for the breeding program. Four terrace paddy levels have been identified, upper (drought), middle (drought prone to favorable) and lower (flooded). This paper reports the change in the breeding program for the drought prone rainfed lowland rice environments of North and Northeast Thailand by incorporating our knowledge on adaptation and on response of rice to drought.     

Replacement policy in dairy herds on farms where heifers compete with cows for grassland—Part 3: A revised hypothesis

A preliminary investigation of replacement policy on dairy farms where heifers compete with cows for grassland suggested that profitability falls as replacement rate increases, because the number of cows able to be milked and the maturity of the herd override the gains in milk yield per cow due to genetic improvement by culling for insufficient yield and by the greater use of a sire of high genetic merit.This hypothesis was inadequate to cover all the situations investigated in two factorial experiments involving changes in herd health status, replacement rate, age at first calving, calving index and the merit of AI sires used in the herd from an initial state for these variables of 0·22, 36 months, 13 months and Standard, respectively.Overall, these was a clear indication that the major influence on profitability was the number of cows in the herd. An increase in replacement rate was not always associated with a fall in profitability, nor was an improvement in yield per cow always associated with a rise in profitability relative to the performance of a control herd after 15 simulated years.The manipulation of replacement rate and age at first calving to achieve an increase in the number of cows in the herd was not necessarily incompatible with a desire for herd improvement either phenotypically (yield per cow) or genetically (herd and heifer genotype), particularly if premium bulls were used.     

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.     

基于SPEI的贵州省分区干旱时空演变特征

[目的]干旱对贵州省水循环及水资源管理系统造成严重破坏,科学合理地认识干旱时空演变对抗旱减灾及社会稳定至关重要。[方法]利用贵州省18个气象站点1960 2012年逐月降水和平均气温数据计算标准化降水蒸散指数SPEI评估干旱,采用M-K趋势检验、B-G分割法、极点对称模态分解法ESMD和反距离权重插值法分析了贵州省分区分时段干旱时空演变特征。[结果]贵州省月、季和年尺度SPEI序列均呈波动下降趋势,其中夏季和冬季SPEI序列变化未通过显著性检验,且20世纪60 90年代,贵州省各分区干湿变化具有较强的一致性,21世纪各分区的干湿变化不具有明显的一致性;以黔西北年SPEI为例,基于ESMD分解法得到3个模态分量IMF和1个趋势项R,从R看出干旱指数整体上呈波动“减小-增大”趋势,分析IMF1-IMF3振荡可得黔西北地区干旱具有2.1、7.6和26.5a的周期特征,且年代际周期26.5a在干旱变化中起主导作用,ESMD法在非线性、非平稳时间序列周期及趋势分析中应用效果较好;依据B-G分割法检测结果,得到1960 1986年、1987 2003年和2004 2012年3个研究时段,2004 2012年黔西北地区的冬旱强度和黔西南地区的春旱频率达到最大,分别为1.82和77.78%,2004 2012年四季干旱强度明显增大,且1986 2012年贵州省高强度干旱呈现由北向南转移趋势,1960 2003年四季干旱高频区呈现由东南向西北转移趋势,1960 2012年各分区四季干旱频率呈现增加趋势。[结论]贵州省各分区呈干旱化趋势,且干旱频率和强度呈现不同程度的增加。