Improving sustainability in dairy cattle systems: Challenges and options

Abstract Dairy cattle systems and their related industry are important to food security, nutrition, and employment worldwide. Over the last decades, there has been an increase in global demand for milk and dairy products, due to both a growing human population and the increasing demand in emerging economies. Concern has been put on the unsustainability of conventional dairy systems, which significantly contribute to greenhouse gas (GHG) and nutrient emissions, and show low profitability, high dependence on external inputs and subsidies, and animal welfare concerns. This review aims to show the central challenges and alternatives regarding the sustainability of dairy farming systems, based on a review of studies carried out in recent decades and years. We identified environmental, social, and economic challenges, as well as options for dealing with them. In environmental terms, we especially highlight GHG and nutrient emissions, with options to address the challenges based on diet changes, rumen bacterial modifiers, plant extracts, herd and manure management, genetic selection, strategic fertilization, urease and nitrification inhibitors, and regulations and taxes on emissions. In social aspects, challenges such as animal welfare, low associativity, and early retirement of dairy farmers can be addressed with pasture-based systems, improved barn design, avoiding overstocking, and strengthening of milk producer associations. In the economic field, rising labor costs, market liberalization, low economic margins, competition from plant-based alternatives and reduced genetic diversity can be addressed through options such as automated milking, subsidies to small/medium-scale farms, limiting herd sizes, innovation, organic or locally based dairy products and increased crossbreeding. We present selected examples of frameworks and case studies aimed at evaluating the sustainability of contrasting dairy systems. Organic or alternative systems had generally better values in environmental and social indicators, such as lower GHG and nutrient emissions, improved nutrient balances, and reduced external input dependence, with similar technical efficiency compared to conventional farms. Likewise, small-scale dairy systems in developing countries using minimum external inputs have been rated positively in environmental indicators related to emissions and soil quality, but their economic performance is dependent on access to fair markets. It is concluded that productivity improvements in the modern dairy industry have been associated with strong negative socioenvironmental impacts. To construct a more sustainable dairy sector, intersectoral dialogue will be central, sharing knowledge, expertise, and skills.