C.M. Yates

Logit models for identifying the factors that influence the uptake of new ‘no-tillage’ technologies by farmers in the rice–wheat and the cotton–wheat farming systems of Pakistan's Punjab

Abstract In the ‘rice–wheat’ and the ‘cotton–wheat’ farming systems of Pakistans Punjab, late planting of wheat is a perennial problem due to often delayed harvesting of the previously planted and late maturing rice and cotton crops. This leaves very limited time for land preparation for ‘on-time’ planting of wheat. ‘No-tillage’ technologies that reduce the turn-round time for wheat cultivation after rice and cotton have been developed, but their uptake has not been as expected. This paper attempts to determine the farm and farmer characteristics and other socio-economic factors that influence the adoption of ‘no-tillage’ technologies’. Logit models were developed for the analysis undertaken. In the ‘cotton–wheat’ system personal characteristics like education, tenancy status, attitude towards risk implied in the use of new technologies and contact with extension agents are the main factors that affect adoption. As regards the ‘rice–wheat’ system, resource endowments such as farm size, access to a ‘no-tillage’ drill, clayey soils and the area sown to the rice–wheat sequence along with tenancy and contact with extension agents were dominant in explaining adoption.

A linear programming formulation of the Markovian decision process approach to modelling the dairy replacement problem

Abstract In modelling the replacement decision in dairy herd management, the most common approach taken is to use dynamic programming to determine the optimal policy by comparing the future expected profitability of an animal to that of its potential replacement. It does not, however, take into account the performance of the entire herd or that of all potential replacements, which is particularly important if replacements originate from the same herd. This paper demonstrates how to overcome this inadequacy by formulating the problem as a multi-component Markovian decision process and then solving it as an associated linear programming model. The proposed methodology is illustrated by using a simple, but realistic, example for determining the optimal replacement strategy for a dairy herd over a 10-year planning horizon. The results show that replacements should be bred from heifer cows in order to increase the genetic turnover; however, no more animals than is necessary should be culled to increase this turnover. It is also shown how to include considerations such as problems of milk quota management, and other similar resource allocation decisions into the model. Additional improvements to the model could involve considering culling of animals suffering from disease.

Evaluation of the potential effects of embryo transfer on milk production on commercial dairy herds: The development of a markov chain model

Abstract The actual or potential availability of new breeding technologies is likely to have far reaching effects on the national bovine herd at the enterprise, farm, regional and national levels. A Markov chain model has been developed to determine the effects of such technologies over a 15-year period. A strategy of using either embryo transfer (ET) followed by two artificial inseminations (AI) or (for animals already derived from ET in an earlier generation) three passes of AI, results in a 55 state model. Typical conception rates, herd structure, milk yield and culling rates are used to model such a strategy and average milk yield increases from 5551 l/annum in year 1 to 6348 l/annum in year 15. The rate of increase is faster in the earlier years at 51 l/annum than in the final years 45 l/annum as initially more animals are bred to ET than AI. Increasing the conception rates to ET increases the milk yields in the early stages, but by year 15 the benefits are minimal. However, varying the genetic lift obtained from the ET has a greater and longer lasting effect on milk yields; increasing the lift from 10% to 15% which increases final milk yield to 6594 l/annum and a 5% lift reduces the final milk yield to 6102 l/annum. The model described is highly flexible and can be adapted easily to consider alternative breeding strategies including twinning and sexing and performance parameters other than milk yield.

Inclusion of nonlinear demand-supply relationships within large-scale partial equilibrium linear programming models

This paper presents a new method for the inclusion of nonlinear demand and supply relationships within a linear programming model. An existing method for this purpose is described first and its shortcomings are pointed out before showing how the new approach overcomes those difficulties and how it provides a more accurate and ‘smooth’ (rather than a kinked) approximation of the nonlinear functions as well as dealing with equilibrium under perfect competition instead of handling just the monopolistic situation. The workings of the proposed method are illustrated by extending a previously available sectoral model for the UK agriculture.