Extended lactation may improve cow health, productivity and reduce greenhouse gas emission from organic dairy cows

The concept of extended lactation should improve cow health and productivity while reducing greenhouse gas emissions per kg milk produced in high-yield organic dairy herds. This is achieved through fewer calvings per year and hence production of fewer replacement heifers. Combined with fewer days dry per cow per year, this will reduce the annual herd requirement for feed while maintaining milk production. This means average milk yield per feeding day (i.e. days lactating plus days dry) should remain the same. Cows will produce milk for the same number of lactations, and thus cows will have longer and more productive lives. Additionally, cow health may be improved as the majority of diseases occur around calving. An on-going project at Aarhus University aims at characterising those cows that can produce milk for an extended period of time, and those cows that cannot. Finally, the project will estimate the overall herd effect of this concept on farm economy and greenhouse gas emissions.