Management, milk production level and economic performance

The research described in this thesis focuses on the relation between dairy herd management, milk production per cow, and gross margin per 100 kg of milk. The study was carried out as an explorative and empirical study. The thesis is composed of five parts.First, relations between technical data, including milk production, economic performance and nutrient losses were determined for a group of 478 farms. This part serves as the empirical basis for the study. Second, literature was reviewed as to the definition of management and management research.Third, based on this knowledge a field study was set up with 38 dairy farms. Technical and economic data were gathered during one year. Repeatability of economic data and milk production data was determined to get insight into the usefulness of one year of data. As could be expected, ranking over years of farms was not completely random. However, the ranking changed over time as well. This indicated that one year of data could be used to determine the influence of fixed effects on technical and economic performance, but year-effects cannot be separated.Fourth, two methodologies that were available to analyse this kind of data were described: Principal Components Regression (PCR) and Partial Least Squares (PLS). An overview of these two methodologies showed the advantage of using PLS for the current study, with a relatively large number of variables and complex relations that have to be determined.Fifth, the results of the analyses of the data set were described. Data were available on management, technical and economic performance. Ma-nagement data were acquired by questionnaires, observations, and a workshop. PLS-models were constructed to determine the relationships between pasture and feeding management and gross margin, milk production level and nitrogen loss. The models were used to define hypotheses for the relationship between pasture and feeding management and gross margin and milk production. Also two models were set up to determine the relationships between mastitis and fertility management and gross margin and milk production.In the concluding chapter, a schematic overview is given of management characteristics that are clearly related to gross margin per 100 kg of milk and milk production per cow. Characteristics of the farmer are a central element of 'the key to success'. A high production per cow is not the best economic option for each farmer. High production per cow should only be advised when the farmer is able to give the herd the detailed attention and interest that are needed