Cattle, straw and system control : a study of straw feeding systems

<p>Straw is an important animal feed in many farming systems of the world. It can be fed in different ways, and for a variety of objectives. An analysis of the role of straw is therefore undertaken to explain the usefulness of straw feeding methods in different systems. Automatically this leads to the question about the role of straw in the drive and shape of farming systems. A review of backgrounds and approaches of Farming Systems Research (FSR) is given to serve as a background for the discussions. After that, this thesis proposes a classification of farming systems that reflects a form of system evolution with different degrees of system control. The classification also provides a framework that tentatively explains the usefulness of straw feeding methods over a large range of systems. Based on feeding trials and a review of literature, a set of feeding values and animal responses are obtained that help to understand the economics of some specific straw feeding methods: urea treatment of straw and/or supplementation with better feeds. It is shown that the feeding of urea treated straw is best feasible in conditions with a) medium levels of individual animal output in terms of milk and meat, b) limited access to better quality feeds and c) access to required inputs such as urea. The calculations are tested from a nutritional angle as well as from an approach that distinguishes between high and low input agriculture, here called closed and open systems. The results are used for thought experiments that explore the possibilities to adjust feed and animals in different combinations for maximum system output. This shows that mutual adjustment of resources and (sub)system production objectives is necessary for maximum system output. This conclusion agrees with concepts from thermodynamics, information theory and ecology, branches of science that also help to explain the drive and shape of systems.