USE OF SYSTEMS-ANALYSIS IN ANIMAL-SCIENCE WITH EMPHASIS ON ANIMAL BREEDING

The units of livestock production are individual animals; the units of livestock breeding are male, female and progeny. These units of production systems interact with the environment and mating systems in a cryptic, nonlinear manner. All of the inputs and outputs of the entire system must be simultaneously considered to evaluate the production or breeding value of individuals within a bounded production system. Systems analysis is defined as a method of conceptualizing a production system and modeling it in mathematical terms so that animal functions and responses across time and space are closely simulated or predicted. Systems analysis provides a method of more systematically organizing knowledge, including ad hoc research results in animal sicence. It is a method of more effectively utilizing research information for current application to increase production efficiency for specific sets of conditions. Since the mathematical model is constructed to describe animal functions and responses there is a feedback stimulus to the more basic subdisciplines; this process encourages an integration of the subdisciplines in animal science. Systems analysis provides a method for overcoming some long recognized major weaknesses. One of these is related to defining merit objectively and realistically especially in terms of production and mating systems; i.e., in terms of production populations rather than in terms of individuals whose effects may not be additive. A 2nd is designing selection and breeding systems to cope with nonlinearity of economic values of characters and to cope with genetic-environmental interaction where the genetic component includes mating systems and the environmental component includes time and space variables, some of which might be volatile measured in terms of livestock generation intervals. Specific selection and mating plans or strategies can be designed for given objectives and environments. The greatest value of systems analysis in animal science may be to encourage a manner of thinking, an ecology philosophy, in teaching, research and extension. Perhaps this in turn will inspire a new wave of originality and development in applied and theoretical animal breeding and composite or production animal sciences.