Feasibility of EVolutionary OPeration (EVOP) as a concept for herd-specific management in commercial dairy herds

Abstract Dairy farming is a complex production system involving biological, technological and human inputs. Therefore, ‘general knowledge of cause and effect’ often seems inadequate to identify and implement optimal management procedures. To solve herd-specific problems, this paper explores the potential of planned experiments for internal use at the farm level to take advantage of local causal relationships. The shift towards larger dairy herds with access to automatic data recordings of a large number of relevant inputs and performance indicators supports the development of management tools that are able to estimate the effect of changes made in daily management on individual farms. The concept of EVolutionary OPeration (EVOP) implies making small systematic changes in production factors or procedures while running the production and continuously evaluating the results. The aim of this study was to develop and evaluate the feasibility of implementing EVOP in commercial dairy herds as an integral part of herd management. The concept of EVOP-Dairy is based on five principles: (1) farmer-driven identification of areas for improvement; (2) herd-specific goals for the interventions to be evaluated in EVOP trials; (3) a short EVOP trial period; (4) simple, but statistically sound, EVOP designs including data access and (5) regular estimation of intervention effects and frequent reporting to the farmer. The project involved three activities: first, visiting a number of dairy farms with the aim of identifying areas for management improvements and to define potential EVOP interventions and relevant designs of EVOP trials; second, conducting a series of EVOP trials to develop data registration, statistical models, analysis and reporting; third, interviewing the farmers to obtain their opinion of the conceptual idea and the process. These activities were documented for the twelve project farms, and five different EVOP trials are described in detail to illustrate the concept. In conclusion, the farmers found the concept a useful management improvement tool, although the EVOP trials created additional work. The EVOP-Dairy statistical models need to include dynamic multilevel data and control for confounding factors when estimating intervention effects, as design with randomization was not feasible in the majority of the identified EVOP trials. Therefore, future development for the EVOP-Dairy should focus on (i) easy to implement and execute interventions, (ii) guidelines to interpret intervention effect when practical conditions hinder fully randomized and well replicated interventions, and (iii) automation of the data analysis and reporting part of the concept.