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The use of sensors for monitoring livestock has opened up new possibilities for the management of livestock in extensive grazing systems. The work presented in this paper aimed to develop a model for predicting the metabolisable energy intake (MEI) of sheep by using temperature, pitch angle, roll angle, distance, speed, and grazing time data obtained directly from wearable sensors on the sheep. A Deep Belief Network (DBN) algorithm was used to predict MEI, which to our knowledge, has not been attempted previously. The results demonstrated that the DBN method could predict the MEI for sheep using sensor data alone. The mean square error (MSE) values of 4.46 and 20.65 have been achieved using the DBN model for training and testing datasets, respectively. We also evaluated the influential sensor data variables, i.e., distance and pitch angle, for predicting the MEI. Our study demonstrates that the application of machine learning techniques directly to on-animal sensor data presents a substantial opportunity to interpret biological interactions in grazing systems directly from sensor data. We expect that further development and refinement of this technology will catalyse a step-change in extensive livestock management, as wearable sensors become widely used by livestock producers.

We compared animal and vegetation responses of a 13 600-ha area under holistic grazing management (HGM) with a similar area under continuous grazing (CGM) in a Patagonian station. Limitations were a dry 2012 −2016 experimental period, poorer soils, and grazing of native guanacos (Lama guanicoe) in the HGM area. Forage standing crop in this area before the experience was lower and remained so during the study: (194 ±31 HGM vs. 244 ±33 kg dry matter . ha −1 CGM). Six monitoring sites showed similar and remarkable (though mostly nonsignificant) vegetation improvements in total cover (10.6% HGM vs. 10.9% CGM) and cover of short palatable grasses (21.4% vs. 23.9%, respectively). Species richness showed small changes ( −1 vs. −6%), bare soil interpatches decreased ( −11.9 vs. −5.4%), and land function indicators of Stability (5.4% vs. 9.9%), Infiltration (12.4% vs. 12.0%), and Nutrient recycling (4.2% vs. 20.6%) increased. Tussock cover changed significantly with grazing management, as it decreased −6% (ns) in HGM and grew 42% ( P = 0.03) under CGM, probably due to coarse tussock forage consumption in HGM. Sheep under HGM were 15% lighter (43.9 ±0.5 HGM vs. 51.7 ±0.5 kg . ewe −1 CGM P < 0.001), ewes scored 28% lower body condition (1.60 vs. 2.25, P < 0.001), and lambing rates were 36% lower (48.3 ±2.1% vs . 74.2 ±1.9%). Rotation ended in 2015 as a consequence of low lambing rates, and sheep body condition and reproductive rates recovered to similar values in both areas. Positive vegetation changes in both areas may be driven by residual effects of destocking 3 decades ago and show that improvement is possible using moderate stocking rates. Although it could be argued that rest periods of HGM may be positive in the long term, its negative effects on animal production should be addressed, and fast regeneration using intense management in these severely restricted habitats should not be expected. Slow, persistent progress under careful management seems achievable under both grazing systems. EEA Santa Cruz Fil: Oliva, Gabriel Esteban. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Santa Cruz; Argentina. Fil: Oliva, Gabriel Esteban. Universidad Nacional de la Patagonia Austral. Unidad Académica Río Gallegos; Argentina. Fil: Ferrante, Daniela. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Santa Cruz; Argentina. Fil: Ferrante, Daniela. Universidad Nacional de la Patagonia Austral. Unidad Académica Río Gallegos; Argentina. Fil: Cepeda, Carla Tamara. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Santa Cruz; Argentina. Fil: Humano, Gervasio. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Santa Cruz; Argentina. Fil: Puig, Silvina. Actividad Privada. Estancia Los Pozos. Santa Cruz; Argentina

Livestock identification is of great significance for achieving precision livestock farming as it is a prerequisite of modern livestock management and automatic behaviour analysis. With respect to cow identification, methods based on computer vision have been widely considered due to their advantage of non-contact and practicality. In this paper, a novel non-contact cow identification method based on fusion of deep parts features is proposed. First, a set of side-view images of cows were captured, and then the YOLO object detection model was applied to locate the cow object in each original image, which was then divided into three parts, head, trunk and legs, by a part segmentation algorithm using frame differencing and segmentation span analysis. Then, three independent convolutional neural networks (CNNs) were trained to extract deep features from these three parts, and a feature fusion strategy was designed to fuse the features, i.e., deep parts feature fusion. Finally, a support vector machine (SVM) classifier trained by the fused features was used to identify each individual cow. The proposed method achieved 98.36% cow identification accuracy on a dataset containing side-view images of 93 cows, which outperformed existing works. Experimental results showed the effectiveness of the proposed cow identification method and the good potential for this method in individual identification of other livestock.

Almost all organisms on earth are adapted to anticipate daily environmental cycles and synchronize with these approximately 24-h rhythms by a circadian clock system. Given its importance to organismal success, the field of chronobiology is rapidly expanding unraveling the complex and integral role circadian clocks play. In applied science, these new insights have led to major advances mainly in the field of medicine. In the field of plant rearing and livestock management, the importance of circadian clocks is already acknowledged. Integrating circadian clocks in insect pest management has mainly received theoretical attention. Applying theory to practice is likely delayed because of the difficulty in managing an open environment. The storage environment is easier to control and therefore basic ideas of integrating circadian clocks to pest management could be applied. A cardinal difficulty in storage management is that storage insects develop resistance to common pesticides. This difficulty can be addressed by various manipulations of the insect's chronobiology. In this review, I discuss the various clock-driven behavioural, physiological and genomic processes that might be considered as sensitive targets for agro-chronobiology control. I further suggest that to promote the discipline of agro-chronobiology, the contribution of previous and current studies to the two following approaches in agro-chronobiology should be examined: 1) treating the vulnerable phases of the circadian clock, and 2) distorting the circadian clock system.

Recirculating aquaculture systems (RAS) require a large investment in construction, equipment and energy. To ensure sufficient return on these investments, RAS operations must be managed meticulously. RAS managers must consider numerous factors related to the biological traits of the fish, logistics, seasonal market demand, and livestock management. RAS that specialize in ornamental fish are faced with particular challenges in that a given species of fish may actually yield several different "products," distinguished, for example, by color, which can be sold at different sizes for different prices. RAS managers need to consider the market prices of different-sized fish in the light of their production costs (cost of food and space, dependent on time in the system). The current study aims to develop an optimization model for the operations management of RAS specializing in ornamental fish. The objective of the model is to maximize annual profit. The methods used include: a general simulation model, built in Arena 11.0®, that seeks to mimic the studied system; an optimization procedure based on response surface methodology (RSM), including design of simulation experiments, stepwise regression (in SPSS® 11.0), and a nonlinear objective function and constraints solved with MATLAB®. The method is demonstrated in a case study—a RAS on Kibbutz Hazorea, Israel, raising ornamental koi fish (Cyprinus carpio).

Habitat suitability for mammal species in grassland/forest ecotones may be affected by changes in abiotic conditions (e.g. light incidence), grazing and burning disturbances, and woody encroachment. We evaluate models addressing the role of such factors on structuring non-volant small mammal assemblages considering (1) only disturbed and (2) all ecotones (disturbed and undisturbed). A complete model (i.e., abiotic gradients, disturbances and woody encroachment) was the most plausible for abundance considering all ecotones, and for niche similarity considering both all and only disturbed ecotones. Niche similarity increased with distance from hydric resources, and abundance with increasing vegetation height. Further, disturbed habitats harbored simplified species assemblages. Habitat selection was detected in all ecotones due to the occurrence of habitat-specialist species on undisturbed sites. We did not find an exclusive influence of woody encroachment on mammal diversity. Patterns described here are relevant for management of productive lands and for biodiversity conservation.

Broiler house systems are operated for the primary purpose of providing the appropriate conditions suitable to have a significant efficiency of animal production. The major environmental conditions in the poultry building are controlling the hygro-thermal parameters (temperature and relative humidity) and contaminant gases (NH3, CO2). In this paper, a poultry house prototype is monitored and controlled using the Supervisory Control and Data Acquisition (SCADA) tool like LabVIEW. A full prototype is designed and an efficient hybrid control strategy is implemented to control in real-time the poultry house climate. In the suggested approach, a Multi-Input Multi-Output (MIMO) fuzzy logic controller (FLC) is combined with a proportional, integral, derivative (PID) controller tuned by fuzzy rules. The proposed method, fuzzy logic, and On/Off controllers were tested by experimental measures and studies in a prototype model over 30 days during hot climates. The comparison results showed that the root mean square error of temperature and relative humidity response with the MFLPID controller (0.8 °C, 1.34%) were lower than that of FLC (1.16 °C, 1.86%) and On/Off controller (2.09 °C, 3.08%). The mean value of CO2 concentration with MFLPID (2461 ppm) was lower than that of FLC (3294 ppm) and On/Off controller (3624 ppm). However, the mean value of NH3 concentration was limited in small value (, Agriculture; Electrical engineering; Energy; Energy conservation; Process monitoring; Animal breeding; Livestock management; Green engineering; SCADA; Poultry farming; MIMO fuzzy; Energy efficiency.

The sustainability of the livestock sector in sub-Saharan Africa is negatively affected by limited access to high-quality fodder in adequate quantities. The effects of climate change further exacerbate feed availability. Therefore, there is a need to develop feasible cost-effective strategies for improving the year-round feed supply. Improved planted forages such as Brachiaria grass have been recommended as one of the strategies of alleviating feed scarcity, especially in drier agro-ecological zones. This study analyses the socio-economic determinants of adoption and the impact of adopting Brachiaria grass for feed sufficiency and increased milk production. Propensity Score Matching (PSM) method was used to assess the determinants and impact of the adoption of Brachiaria grass. Empirical results indicate that the adoption of Brachiaria grass led to a significant increase in milk production by 27.6% and feed sufficiency by 31.6%. The positive impact of Brachiaria grass is consistent with the role of agricultural technologies in improving the productivity, income, and welfare of smallholder farmers. The adoption of Brachiaria grass is influenced by age of farmer, tropical livestock unit (TLU), type of animal breed, perceived benefits of the technology, access to extension, and farmer group membership. The study recommends holistic policy approaches that promote the widespread adoption of Brachiaria grass. There is also a need for an effective information dissemination pathway for Brachiaria grass., Brachiaria grass; feed sufficiency, milk productivity; propensity score matching; planted fodder technology; climate-smart; agricultural policy; Animal Nutrition; Cattle; Livestock Management; Agricultural Economics; Agricultural Policy; Agricultural Technology; Economics

The accurate and reliable counting of animals in quadcopter acquired imagery is one of the most promising but challenging tasks in intelligent livestock management in the future. In this paper we demonstrate the application of the cutting-edge instance segmentation framework, Mask R-CNN, in the context of cattle counting in different situations such as extensive production pastures and also in intensive housing such as feedlots. The optimal IoU threshold (0.5) and the full-appearance detection for the algorithm in this study are verified through performance evaluation. Experimental results in this research show the framework’s potential to perform reliably in offline quadcopter vision systems with an accuracy of 94% in counting cattle on pastures and 92% in feedlots. Compared with the existing typical competing algorithms, Mask R-CNN outperforms both in the counting accuracy and average precision especially on the datasets with occlusion and overlapping. Our research shows promising steps towards the incorporation of artificial intelligence using quadcopters for enhanced management of animals.

The aim of this paper is to present the results of the biometrical analysis carried out on cattle, sheep/goat and pig measurements from a number of Spanish archaeological sites, dated between Roman and post-medieval times. The results show that important transformations occurred in livestock management, as it is visible through various changes in the body size of the main domesticates. The Romans had a great interest in improving 1 cattle breeds, 2 while during the Middle Ages most effort was put in improving sheep breeds. The size of the three taxa decreased after Roman times, reaching their minimum size between the 8th and 9th centuries, probably in association with changes in livestock management, including free-range keeping and non-selective breeding.

The typical steppe is a major region for sheep meat production in north of china, but most of the area has now become degraded inducing serious constraints for livestock management. In this study we compared the effects of the grazing management strategies on herbage mass (HM), sheep intake, diet chemical composition, and digestibility, and on live weight gain (LWG) of sheep grazing in typical steppe of north china during the growing season. Five grazing management strategies which have different stocking rate at different season were evaluated. The grazing managements were no grazing in the late spring and stocking rate at 9.3 and 6.7 sheep/ha in the summer and autumn (SA1); no grazing in the late spring and stocking rate at 6.7 and 9.3 sheep/ha in the summer and autumn (SA2); continuous grazing at 9.3 sheep/ha through all seasons (SA3); continuous grazing at 9.3 sheep/ha through late spring and summer and changing to 6.7 sheep/ha in the autumn (SA4); continuous grazing at 6.7 sheep/ha through all seasons (SA5). The results showed that HM decreased from 1.0 t DM/ha at SA1 and SA2 to 0.34–0.37 t DM/ha in SA3 and SA4 (P

Excavations at the Iron Age settlement of La Hoya in north-central Iberia, which was attacked between the mid-4th and the late 3rd centuries BC, provided fossilized scenes of devastation and death but also an extraordinary opportunity to analyze lifeways. Here, we conduct stable carbon and nitrogen isotope analyses of human, animal and plant remains to reconstruct aspects of subsistence. The results indicate a mainly C3-based subsistence economy, focused on the cultivation of cereals and the herding of domestic animals, particularly pigs, as the archaeological data support. Although C4 plants are less abundant, they may have played a key role in infant and child feeding practices. Inferred differences in livestock management, as well as in manuring intensity and management in relation to water resources between crops, suggest a well-established farming economy. Inter-household variability in crop-cultivation and land-use suggests household production and subsistence autonomy, and suggests the existence of socio-economic inequalities within the community.

Temperate grasslands are generally considered carbon (C) sinks, but climate and management likely affect whether they accumulate or lose C on an annual time step. The North Central Region of the United States contains highly productive improved pasture that is used exclusively for livestock grazing and mechanical harvest. The objective of this study was to use a net ecosystem carbon balance (NECB) approach to estimate C accumulation or loss in subhumid pastures under four typical livestock management practices: management-intensive rotational grazing (MIRG), continuous grazing (CONT), haymaking (HARV), and land set aside with no harvests (NONE). MIRG lost significantly less C in 2006 than all other treatments, and in 2007 MIRG was the only treatment that had a positive NECB. For 2006, our model resulted in an average change of � 236 615

We study the economy and ecology of sheep farming under future climate change scenarios. The analysis is at the farm level and includes two different categories of the animals, ewes (adult females) and lambs with a crucial distinction between the outdoor grazing season and the winter indoor season. The model is formulated in a Nordic economic and biological setting. During the outdoor grazing season, animals may experience growth constraints as a result of limited grazing resources. The available grazing resources are determined by animal density (stocking rate) and weather conditions potentially affecting the weight, and hence, the value of lambs. Because empirical evidence suggests that climate changes, e.g., increased temperature, have contrasting effects on lamb weights depending on the location of the farm, the spatial effects of such changes are analyzed.

On the Ground Properly applied grazing management may reduce fire frequency in annual grass–invaded sagebrush communities. Grazing can be a cost-effective tool for reducing fire potential and protecting sage grouse habitat from burning. Squaw Valley Ranch has been able to reduce fire frequency through preventive practices, which include intensive, appropriate livestock management on private lands. Publicly managed lands associated with the ranch have experienced large and frequent fires, a hindrance to improving or maintaining sage grouse habitat.

Cattle grazing effects on aquatic macroinvertebrates were assessed in a 4-year experiment of a mountain stream in northeastern Oregon. From 1996 through 1999, 10 cow–calf pairs were introduced into 6 experimental units along the stream for 42 days between July and September, and effects on aquatic macroinvertebrates were compared with 3 units in which no grazing occurred. Streambank and geomorphological variables were also measured to provide context for interpretation of effects on aquatic macroinvertebrates. Macroinvertebrate response to grazing was subtle, indicated by significantly lower abundance in grazed units. We measured more profound effects on streambanks: grazing caused an average decrease of 18% in bank length of the highest stability/cover class and caused an average increase of 8% in the lowest condition class over the course of each summer. By June of each following year, banks had recovered to their previous June condition, but grazing each summer caused a progressively larger decline in bank condition by September. Streambank effects were accompanied by an increase in cobble embeddedness over time in grazed units and were correlated with grazing-associated stream widening. Treatment effects were overwhelmed, however, by a profound decline in the abundance of most macroinvertebrates over the study period, with a drop in September 1999 to 14% of the initial September abundance of 1997. While the drop was more precipitous in grazed units, declines were common to all study units, suggesting that something more widespread affected the system during this time. Logging on lands just upstream of the study area in 1998 and 1999, in which trucks drove through the study stream without the benefit of a culvert, sent sediment plumes into the study area each of those 2 years and could have caused the precipitous decline in aquatic macroinvertebrates.

Metadata only record In the Sahel region of West Africa, the traditional organization of the population and the grazing land avoided overexploitation of pastures. Since independence in the 1960s, grazing lands have been opened to all without specific guidance, and the vulnerability of the pastures to degradation has increased. Rotational grazing is postulated as a possible solution to provide higher pasture productivity, higher animal loads per unit land, and perhaps improved soil carbon storage. The objective of this study was to conduct a simulation-based assessment of the impact of rotational grazing management on pasture biomass production, grazing efficiency, animal grazing requirement satisfaction, and soil carbon storage in the Madiama Commune, Mali. The results showed that grazing intensity is the primary factor influencing the productivity of annual pastures and their capacity to provide for animal grazing requirements. Rotating the animals in paddocks is a positive practice for pasture protection that showed advantage as the grazing pressure increased. Increasing the size of the reserve biomass not available for grazing, which triggers the decision of taking the animals off the field, provided better pasture protection but reduced animal grazing requirements satisfaction. In terms of soil carbon storage, all management scenarios led to reduction of soil carbon at the end of the 50-year simulation periods, ranging between 4% and 5% of the initial storage. The differences in reduction as a function of grazing intensity were of no practical significance in these soils with very low organic matter content, mostly resistant to decomposition. SysCoor-2 (Farm/Enterprise)

Livestock management, as a means of determining the extent and value of nutrient flows in agricultural landscapes, is already well understood and exploited by small-scale farmers in Asia. This paper highlights the biological interfaces in smallholder agricultural systems where animals exert the greatest influence upon nutrient cycles, and suggests that these should form the focus of scientific effort to elucidate the key elements of the biological processes at work. Two case studies of intensive mixed farming systems are presented from the uplands of Java, Indonesia and the Mid-Hills of Nepal. These examples show how management practices have developed over centuries to enhance the contribution that livestock make to motivating and moderating nutrient flows on very small and continuously cultivated land holdings. The paper concludes by emphasising that there is an urgent need to understand the biological mechanisms that enable livestock to contribute to the sustainability of intensive smallholder agriculture.

A technique for the rapid field assessment of African animal trypanosomosis (AAT) was developed during studies in the Gambia. This involved gathering indigenous information from rapid-appraisal questionnaires addressed to local informants, the results of single tsetse surveys and evaluations of the prevalence of trypanosome infections in village cattle. Local informants included livestock owners and herdsmen and trained personnel such as livestock assistants. The answers to the questionnaires were weighted in order to translate them into semi-quantitative ranked estimates (zero, low, medium, high or very severe) of the severity of AAT problems. A similar ranking was also defined for tsetse and prevalence data in the Gambia. The three assessment methods generally gave complementary results leading to similar conclusions about the severity of tsetse-trypanosomosis problems in a survey area; inconsistencies usually suggested that additional information was needed. The rankings of AAT intensity were used to develop management guidelines for minimising the impact of AAT at different levels through control interventions or improved livestock management. The methodology was designed to provide reliable, up-to-date and cost-effective assessments of AAT problems. Emphasis was placed on the importance of the involvement, priorities and perceptions of village livestock owners and herdsmen in making these assessments.

Mountain areas are particularly sensitive to climate change. Seasonal and annual variations in climate already strongly influence agro-ecosystems, and although there is much speculation about the precise effects in such areas, any response of the communities will emerge from existing coping practices. Using examples from the High Atlas in Morocco, the paper explores the implications for livestock management, arboriculture and tourism. Although the local agro-ecosystem may prove resilient initially, the need to change tenure conditions and other rules of management may lead to conflict which exceeds the capacity of local institutions to resolve. At the same time national considerations may also draw the state more fully into conflict with mountain communities over resource use. However, the paper argues that these issues are just as likely to emerge from the evolution of the national economy as from climate change.

Metadata only record In the Sahel of West Africa, the productivities of rangelands, croplands and livestock are inextricably linked. Cattle, sheep and goats graze rangelands and crop residues, and their manure/urine is used to fertilize crops. Rangelands provide important feeds during the manuring period, resulting in a net nutrient transfer from rangelands to croplands. This paper examines the sustainability of nutrient transfers in integrated rangeland/cropland systems of the Sahel by examining the impact of grazing on rangeland vegetation structure and floristic composition, the impact of livestock on nutrient balances of rangelands and croplands, and the role of livestock in offsetting nutrient deficits through manuring. Rangeland nutrient balances are in equilibrium (inputs = offtakes) whereas croplands lack the internal capacity to replenish nutrient offtakes in grain (as food) and crop residues (as feed). Although soil nutrient mining is of general concern for the Sahel, local management practices of some farmers (e.g. corralling animals overnight on fields between cropping seasons, use of fertilizers) offset cropland nutrient deficits. The number of additional livestock, and their feed requirements needed to supply sufficient manure to offset cropland nutrient deficits, depend on rangeland and cropland productivity, livestock production goals, and management strategies of farmers. Livestock must be managed so they do not deplete the nutrient supply of rangelands in order to increase the manure supply for improving cropland productivity. Sustained rangeland productivity in the Sahel will depend largely on producing alternative feeds derived mostly from croplands. Land use and tenure policies that inhibit livestock mobility and, therefore, farmers' access to the manure of pastoralists herds, will greatly undermine the resilience of Sahelian rangelands, and increase the need for other external nutrient inputs such as fertilizers to prevent declines in soil fertility and crop yields. (CAB Abstract)

Opal phytoliths can easily be extracted from herbivore dental calculus and examined to gain data for the reconstruction of prehistoric herbivore diet. The extraction process is a simple, quick and inexpensive three-step procedure. It consists of one or two distilled water washes to control and assess contamination and a final wash with dilute hydrochloric acid. A pilot study conducted on barnyard animals (cow, sheep and pig) from the American Colonial period site of Hampton, Virginia, demonstrates that dental calculus phytolith assemblages can provide data on herbivore diet that can be used to reconstruct livestock management practices and ecological change.

Reproductive performance of camels in two herds in Ras Al-Khaimah Emirate, United Arab Emirates, was assessed by analysis of records gathered over 5 1 2 years. Ages at first mating and first calving were 43·1 and 55·3 months. Days open was lower in one herd (319 and 352 days) possibly due to earlier weaning of calves, this being reflected in shorter calving intervals (22·9 and 26·6 months). There were 1·63 services per conception, most matings taking place in October-January. Some calving (8·7%) in April-May indicates the possibility of extending the breeding season under field conditions. Advanced ages at first calving, long calving intervals and seasonal breeding are the main reasons for poor reproductive performance in traditional camel herds in the United Arab Emirates.

A preliminary investigation of the factors affecting traditional camel production in the Al-Qasim region in Saudi Arabia was undertaken to identify areas of research suitable for more intensive on-farm studies. Five farms were studied during a 4-month period and all aspects of management, including quality of feed on offer and feed intake were examined. Results indicated that range grazing was incapable of supplying all the nutritional requirements and that animals would need to be supplemented with barley and lucerne especially during the breeding season.

A model of the dryland farming system in the eastern wheatbelt of Western Australia is briefly described. The model, named MUDAS, explicitly accounts for climatic risk and dryland farm management responses to such risk. Results from this model are compared with those from a model based on expected values and which therefore excludes climatic risk. The performances of the models are compared assuming two price scenarios. Results from the models show that climatic risk and its associated farm management responses lead to decisions often different from those generated by sole consideration of expected values. Levels of activities selected, in the model based on expected values, are often substantially different from those generated in MUDAS. However, the expected value model that ignores climatic risk and tactical responses to such risks still correctly identifies the desirable direction of strategic response to a change in price regime. Tactical decision-making, in response to climatic risk, is shown importantly to contribute to farm profit and to influence production decisions including the mix of enterprises. Profitable tactical decision-making in response to climatic risk causes wide variation across seasons in crop and pasture areas and crop and livestock management, and overall greatly modifies the farm management decisions that might otherwise be based on expected values. Results from MUDAS show that rigid adherence to rotations is not the most profitable managerial response to climatic risk. Instead managerial flexibility causing marked changes in crop and pasture areas across seasons is more profitable. The value of tactical decision-making and managerial flexibility illustrated in the MUDAS results points to a potentially profitable area of research and extension, this being the development of information or innovations that facilitates tactical decision-making.

Malodorous emissions from livestock buildings are caused by waste products, particularly. manure. The published information on how waste management practices influence odour production and emission has been reviewed, but the shortage of objective odour measurements makes it difficult to give practical recommendations with confidence. Some recommendations for research are, however, proposed. The main factors in livestock management have been analysed; these are waste removal,waste decomposition, design of the floor of the building, treatments that may be applied to the waste within the building (e.g. changing its pH) and the use of bedding materials. The interactions between most of these factors confound the analysis, but the evidence indicates that the main options for reducing odour production, odour emission or odour nuisance are frequent waste removal from buildings, or the prevention of anaerobic conditions developing in the waste. Reduction of the moisture content of the waste has been reported to reduce odour production. This may work by inhibiting the development of anaerobic conditions and it may explain why the use of bedding has been found to reduce odour. However, adequate odour measurement data on using different bedding materials and on other waste management practices must be gathered before any firm conclusions can be drawn. The relevance of information on emissions of ammonia from livestock buildings is briefly considered. Although ammonia concentrations in air do not show a good correlation with odour strength, nevertheless any step taken to reduce the ammonia emissions from a livestock building ought also to reduce the odour emissions and vice versa.

Land use policy is often developed without regard to historical considerations, even though policy may fail because it is familiar to local people who have found it to be inaccurate and inappropriate. Between 1931 and 1981 officials consistently described north-eastern Botswana as severely overgrazed and in imminent danger of ecological disaster unless destocking took place. Over the same period the cattle population tripled, while enforced destocking caused hardship to local cattle holders. The contrast between local experience and official prescription over 50 years suggests why present-day residents are sceptical of official rangeland policy. The design of rangeland policy and range and livestock management projects would benefit from considering the history of local experience with official policy and advice.

Routine methods for predicting animal performance for use in livestock management are changing. Static systems of feed requirements are beginning to be replaced by dynamic simulation models able to characterise animal response to a wider range of input conditions than those accommodated in traditional systems. This paper summarises work conducted over the last seven years aimed at developing models of animal growth. The work has been based on the assumption that critical determinants of growth identified in causal models representing factors associated with cellular hyperplasia and hypertrophy can be aggregated to the whole animal level and will result in greater accuracy and wider application than is usual with more empirically defined models. The methodology used in model development has been described elsewhere [ 241.

IDEAS is a microcomputer database package developed by the International Livestock Centre for Africa. It has been designed as a tool for improving decision making in animal production systems in developing countries through the collection of data. In addition to storing and retrieving production data, the package offers users management decision facilities based on data analysis techniques. This article provides a brief history of the development of IDEAS and presents findings from a questionnaire recently issued to users to assess the uptake of IDEAS in African production systems during the first year of its release.

The ‘Mouton de Case’ is a small-scale stall-fed system of sheep fattening current in West Africa. Most fattened animals are males, kept for slaughter at the annual Moslem Feast of the Sacrifice (tabaski). More than 25% of total annual offtake in local sheep flocks occurs in relation to this feast. In two local agropastoral sub-systems more farmers kept stall-fed sheep in an irrigated rice sub-system (39%) than in a rainfed millet sub-system (24%). Farmers in both systems fed approximately two animals. Supplementary feed is mainly cut grass and tree leaves and some agricultural by-products. Average daily gains of Mouton de Case were, at 117 g, almost twice those of extensively reared animals (60 g) of the same type.

The liveweight of a free-ranging cow is constantly changing. If she is weighed automatically upon entering a corral before drinking water, a liveweight profile results which can be used to manage her individual performance. Using a manual procedure and weighing the same cow every 28 days also results in a liveweight profile. To determine how the amount of information contained in the 2 weighing procedures differed, the same cows of an experimental herd were weighed using both procedures. The resulting data referred to 1281 manual and some 40 000 automatic weighings, which were then classified into the phenological stage of the grazed plants and the physiological stage of the cow. By assuming that a cow is biologically the same within a 7-day period, and with as little as 1 weeks' data, an 11% change in a cow's liveweight can be detected 90% of the time with only one additional automatic weighing. Real changes in liveweight as little as 5% can be detected at the same rate if more than a single weighing is observed. Therefore, automatic weighing not only can be used to estimate the effects of past management practices, but also can be useful in making sound day-to-day livestock management decisions on individual animals.

Recommendations are made on the data that need to be collected and stored by computer systems in livestock recording for dairy herd management so that different sources of data collected by different computer systems can be available for wider statistical and epidemiological analysis. The emphasis has been put on management rather than clinical veterinary data. The recommendations are based on discussions held by a working party established to consider the application of computer systems in livestock management in the United Kingdom.