Abstract for: The Dynamics in the Dairy Cattle Sector: Policies on Cow Milk Production Can Reduce Greenhouses Gas Emissions and Land Use
This paper was aimed to understand the key components affecting the dynamics of world milk production and consumption and their effects on CO2 emissions (CO2eq) and grassland use. The model had two major balancing loops: world milk demand (MD), and world milk production (MP). The MP consists of three balancing loops: cow number (CN), cow productivity (CPr), and feed cost; they represented the indirect and direct ways to change the MP rate in order to meet MD, and the positive relationship between cost and demand of feed, respectively. The model consisted of 6 sub-models: people and milk market; cows; milk production; energy requirements; economics; environment. Simulated scenarios were performed between 2007 and 2052. The structural loops affected the output behavior: when MD>MP farm profitability described goal seeking patterns, while when MP>MD, it described constant oscillatory patterns. Scenarios with low CPr did not meet the MD. Scenarios with greater CPr and policies to improve CPr and cattle efficiency met the MD while reducing the CN and used fewer inputs per kg of milk. The model suggested that CPr and cattle nutritional efficiency were the key factors in mitigating anthropogenic environmental impacts by reducing total energy demand, grassland use, and CO2eq/kg milk.