Co‐operative Research in Agriculture and the Provision of Input/Output Coefficients

Wragg, S.R.

doi:10.1111/j.1477-9552.1970.tb01379.x

Cited by 8 publications

(4 citation statements)

References 3 publications

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“…These could be integrated with the national database under development by Meat NZ and Wools of NZ for sheep breeding (Geenty 1998). Model development will raise, again, the perennial issue of poorly defined input:output production functions for pastoral farms (Wragg 1970).…”

Section: A Modelling Approach Vs National Standardsmentioning

confidence: 99%

Standardisation between livestock classes: the use and misuse of the stock unit system

Parker¹

1998

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The stock unit (SU) system is used extensively in New Zealand agriculture. These applications include inter- and intra-farm comparisons, rural lending and valuation, and farm system design and analysis. The livestock classes and performance levels to which SU conversion factors are applied has increased significantly since Professor Coop defined the ewe equivalent (EE) system, and now includes deer, goats and other non-conventional livestock species. This has led to a proliferation of SU values and their incorrect application and interpretation, especially in between-farm comparative analysis. Benchmarking provides a more economically rational way of improving the profitability of livestock farms than the use of standards based on SUs. Obtaining agreement on the specifications of animal-pasture-financial models to allow users to derive substitution rates between stock classes according to their farm's resources and management practice is preferred to publishing national standards for SUs. Keywords: comparative analysis, livestock classes, standardisation, stock unit

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Section: A Modelling Approach Vs National Standardsmentioning

confidence: 99%

Standardisation between livestock classes: the use and misuse of the stock unit system

Parker¹

1998

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“…Deficiencies in the reported results include: inadequate information about site and weather conditions at the time of, and subsequent to, N fertiliser application; results expressed simply as a total DM response to N rather than also as the temporal distribution of extra DM production; limited information on animal responses following N application; and a relatively narrow range of site conditions and application dates, especially in relation to hill country pasture. It would be cost-prohibitive, however, to conduct the full series of experiments that are necessary to generate the input-output relationships (Wragg 1970) required for economic evaluation and management decision making. An alternative low cost method of obtaining these data is to use 'experts' to define, on the basis of their substantial research experience with N fertilisers, the nature of the pasture response function to N under different field conditions (Wright 1993).…”

Section: Limitations Of Current Research Data For Risk Managementmentioning

confidence: 99%

Risk management for tactical nitrogen fertiliser applications in pastoral farming

Parker¹,

Dake²,

Wright³

et al. 1994

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The physical and financial outcome from the tactical application of nitrogen fertiliser in pastoral farming is always uncertain. A management policy is therefore required to minimise uncertainty. Listing the sources of production, price and financial risk for nitrogen fertiliser inputs and identifying management actions that mitigate these creates awareness of risk and indicates where management effort can be focused. Data obtained from traditional pasture response research trials are not well suited to decision-making at the farm level. However, results obtained using an expert knowledge approach demonstrated that response relationships for nitrogen can be generated in a form which is more applicable to decision-making situations faced on farms. These data can be adapted to a decision tree framework which allows the likelihood of uncertain events to be formally incorporated in the estimation of financial returns for alternative application decisions for nitrogen fertiliser. A bull beef example showed that highest returns for different weather scenarios were consistently obtained for the application of 50 kgN/ha (as urea); rather than O or 25 kgN/ha. Keywords: economics, fertiliser, nitrogen, pastures, risk

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“…Reliable recommendations can be obtained only if functions used to predict these items are realistic. Much has been written in the past about the difficulties encountered in obtaining realism (see, for example, Blaxter, 1961; Barnard, 1969) and in particular little progress has so far been made towards a satisfactory understanding of input/output relationships in livestock, mainly because of the very large resources needed to produce suitable data (Wragg, 1970). Despite the continuing ignorance, however, economic studies have been issued purporting to provide nutrient level * Present address: W.I.A., Netherlands Soil Survey Institute, P.O.…”

Section: Introductionmentioning

confidence: 99%

Problems in determining the best levels of essential nutrients in feedingstuffs

Lerman

Bie

1975

J. Agric. Sci.

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SUMMARYTwo obstacles to achieving diets which maximize farm profits are discussed: (1) the continuing inability to predict reliably the response of animals to a diet with any given composition, and (2) batch-to-batch variation in the true nutrient content of a diet with a fixed nominalcontent. With the aid of simple practical examples it is demonstrated that diet recommendations can be more sensitive than might be expected to the type of function used to predict response, and that variation in dietary nutrient content may reduce farm profits (though the size of the reduction is not clear because of (1) above).

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Co‐operative Research in Agriculture and the Provision of Input/Output Coefficients

Cited by 8 publications

References 3 publications

Standardisation between livestock classes: the use and misuse of the stock unit system

Standardisation between livestock classes: the use and misuse of the stock unit system

Risk management for tactical nitrogen fertiliser applications in pastoral farming

Problems in determining the best levels of essential nutrients in feedingstuffs

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