In the proposed project, we will explore the benefits of increasing the longevity of dairy cows under Swedish conditions by changes in herd management. We will focus on effects on methane emissions by modelling, using existing data from the Swedish Official Milk Recording Scheme and results from an advanced computer simulation tool, SimHerd, to evaluate farm profitability. Milk from cows in diffferent lactations will be analysed for processing traits.
Hypotheses: Methane emissions will decrease by increasing herd longevity since the productive life of the cow will be longer in relation to the time until productive life starts. Reduced recruitment of heifers will increase the economic profitability on the farm since heifer rearing is associated with significant costs. By increased longevity in the herd, total milk yield from the herd will increase but raw milk composition and processing properties will not be negatively affected.