Optimizing rotational grazing in sheep management systems

Barioni, L. G.; Dake, Chris K.G.; Parker, W. J.

doi:10.1016/s0160-4120(99)00051-3

Cited by 10 publications

(2 citation statements)

References 4 publications

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“…The wholefarm simulation model of a grazed sheep enterprise described by Cacho et al (1995) may well provide a useful template as it not only considers the balance between pasture supply and animal demand in terms of ME, but it also takes into account many of the factors encountered in the Cicerone farmlet experiment, including the need to allow for flexibility in paddock subdivisions, pasture growth, fodder conservation, the movement of animal mobs between paddocks and of animals between mobs, animal growth and reproduction. Also, Barioni et al (1999) have provided an example of the value of using a modelling approach based on a genetic algorithm to optimise grazing within whole-farm systems. There would of course be additional value if the risk associated with alternative management options could also be assessed as described by Cacho et al (1999).…”

Section: Discussionmentioning

confidence: 99%

Estimating the balance between pasture feed supply and demand of grazing livestock in a farmlet experiment

et al. 2013

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Abstract. Data from the Cicerone farmlet study were used to quantify the balance between pasture feed supply and the demand from grazing livestock, in terms of metabolisable energy (ME), on three differently managed farmlets (each of 53 ha) on the Northern Tablelands of New South Wales, Australia. Farmlet A had a high level of pasture renovation and higher soil fertility than the other two farmlets and employed flexible grazing management over eight paddocks. Farmlet B was designed to represent management 'typical' of the region and had the same grazing management and number of paddocks as farmlet A but moderate levels of pasture renovation and soil fertility. The third farmlet (C) had the same level of inputs as farmlet B but practised intensive rotational grazing over 37 paddocks.Regular measurements of the feed supply, namely herbage mass and quality, pasture growth and supplement fed and of feed demand were assembled to provide monthly estimates of the balance between feed supply and animal demand of all classes of livestock run on the experiment over its duration of 6.5 years. The significantly greater stocking rate, liveweight and reproductive rate of sheep reached on the higher input system (farmlet A) meant higher levels of ME were required to satisfy the nutritional demands of these animals. As only limited measurements were taken of animal intake, it was assumed that the supply of ME was derived from pasture growth and supplement fed. Using key livestock management dates and measurements of liveweights, the changes in the energy requirements of each class of animal were calculated and aggregated to provide an estimate of overall livestock energy demand over time. Subtracting the energy demand from the estimated energy supply provided a partial net energy balance.Measurements of the rates of change of green herbage during grazing events were found to be highly dependent on stock density with farmlets A, B and C recording rates of change of up to -50, -30 and -200 green DM/ha.day, respectively.Over a series of generally drier-than-average years, the ME supplied in pasture growth and through supplementation was at times inadequate to meet the energy demands of the livestock, resulting in periods during winter when the partial energy balance became negative. Similar feed deficits were observed for all three farmlets, suggesting that they were overstocked to a similar extent. In spite of the divergence in the stocking rate supported by each farmlet, the similarity of the ME balances between farmlets suggests that no farmlet was subjected to bias because of decisions relating to feed supply and demand. The analyses presented suggest there is considerable potential for practical paddock and grazing management to be improved if more timely and regular assessments can be made of changes in the feed energy supply using satellite images of normalised difference vegetation indices and feed energy demand using calculations of the ME required by grazing livestock.

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Section: Discussionmentioning

confidence: 99%

Estimating the balance between pasture feed supply and demand of grazing livestock in a farmlet experiment

et al. 2013

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“…Computer simulation may aid managers to compare prospects besides providing an objective way to define expected levels of performance for each scenario in livestock production. Several predictive computer models have been successfully delivered as planning tools for livestock production either through scenario analysis [20,25] or optimization [3,52,16]. They may provide the best expected trajectories of indicators of a system performance prior to the implementation of the plan but they will rarely be a satisfactory match to the actual systems behavior, so monitoring and controlling are needed [44].…”

Section: Literature Review 21 Beef Production Managementmentioning

confidence: 99%

Parameter fitting for individual growth through data assimilation applied to beef cattle

Henrique Pereira

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Os criadores de gado frequentemente tomam decisões em um ambiente desafiador, onde dados objetivos são escassos e ruidosos, enquanto têm de lidar com mudanças climáticas, diferenças fenotípicas entre animais, bem como outros fatores. O planejamento objetivo baseado em dados de crescimento animal e previsão de produtividade ainda carece de instrumentação com tecnologias robustas e escaláveis. Aproveitando as tecnologias cada vez mais comuns de coleta automatizada de dados, esta pesquisa propõe o uso de técnicas de assimilação de dados, em conjunto com dados de crescimento animal, para melhorar as previsões produzidas por modelos de crescimento animal, possibilitando o planejamento de sistemas pastoris em um sistema de pecuária. Os dados de crescimento animal foram obtidos usando balanças que medem automaticamente o peso do gado, identificando individuos por meio de brincos RFID. Espera-se que os resultados obtidos contribuam para o avanço do estado da arte na previsão de modelos de crescimento animal e auxiliem no manejo e manutenção de sistemas de produção pecuária.Palavras-chave: Sistemas dinâmicos, filtragem de Kalman, identificação de sistemas, RFID, admnistração da produção -processamento de dados

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Farming system design to feed the changing world. A review

Martin

Martin‐Clouaire

Duru

2012

Agron. Sustain. Dev.

116

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Agricultural production is unstable as a result of complex, dynamic and interrelated factors such as climate, markets and public policy that are beyond farmers' control. Farmers must therefore develop new farming systems incorporating innovations in objectives, organization and practices adapted to changing production contexts. As a consequence, agronomists have expanded the "farming system design" field of research. A variety of quantitative and qualitative design approaches have been developed to support the analysis of current farming systems and the design and evaluation of alternatives. A comprehensive literature assessment is lacking for this emerging field of agricultural science. Here we review 41 farming system design approaches using computer models. Our main findings are the following: (1) the reviewed literature do not make reference to the theoretical approaches from the field of design science. (2) Two categories of farming system approaches can be distinguished: optimisation approaches, and participatory and simulation-based approaches. These two categories are connected to two of the main design science theories. (3) For optimisation approaches, farming system design is mainly seen as a problem-solving process. Emphasis is placed on the computational exploration of the solution space by a problem-solving algorithm. (4) For participatory and simulation-based approaches, conceptualization of the design problem is central to the farming system design process. The subsequent exploration of the solution space relies on the creativity of humans. (5) Optimisation approaches, and participatory and simulationbased approaches are oriented towards the development of exploitative rather than exploratory innovations. Exploitative innovations involve the exploitation of available knowledge while exploration innovations build on knowledge created in the course of the design process.

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Optimizing rotational grazing in sheep management systems

Cited by 10 publications

References 4 publications

Estimating the balance between pasture feed supply and demand of grazing livestock in a farmlet experiment

Estimating the balance between pasture feed supply and demand of grazing livestock in a farmlet experiment

Parameter fitting for individual growth through data assimilation applied to beef cattle

Farming system design to feed the changing world. A review

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