ASSOCIATIONS BETWEEN SOME SOCIAL, STRUCTURAL AND TECHNICAL FACTORS AND THE MILK-PRODUCTION OF DAIRY-COWS - A STATISTICAL-ANALYSIS BASED ON THE SWEDISH MILK RECORDING-SYSTEM

Differences in milk yield between dairy cow herds in Sweden are substa ntial despite apparent similarities in technical conditions and geneti c makeup. In practice this means that the same resources can be utiliz ed more or less efficiently for milk production. The present paper is part of a research project with the objective to identify and describe the social factors, a. o. attitudes and behaviour of the individual f armers, that can further explain the variation in milk production betw een Swedish herds. The first part of the study is presented in this pa per and consists of calculations and analyses of the relations between certain objective variables and milk yields, milk quality and reprodu ction. The result of the statistical analysis showed that age of the f armer, farm size and presence of a grain drier were negatively related to milk yields, while herd size and presence of a barn hay drier and a silo were positively related to milk yields. There was no difference in milk yields between herds dominated by the Swedish Red and White b reed or the Swedish Friesian breed while mixed herds had lower milk yi elds. The statistical analysis and evaluation of the results will be u sed when selecting farmers for in depth interviews and participant obs ervation for the next phase of the project. The criteria for age of th e farmer, herd size, breed, farm size, presence of a barn hay drier, g rain drier and silo will be chosen in order to eliminate any differenc es in milk yields due to these factors.