Abstract
Animal production exerts significant demands on land, water and food resources and is one of the most extensive means by which humans modify natural systems. Demand for animal source foods has more than tripled over the past 50years due to population growth and dietary change. As a result, the livestock sector has transitioned towards intensive and concentrated production systems. Typically, studies have divided types of animal production into intensive, mixed and grazing production systems. However, because a large percentage of animal production originates from mixed systems, dividing by such production types can make it difficult to quantify competition for crop production between direct human consumption and use as feed. To this end we employ a calorie-based approach to determine which animal calories were 'free' - in that they did not compete with human consumption for crop use - and consider to what extent alternative scenarios could have reduced this competition between food and feed. We find that growth in non-feed animal systems has only been able to keep pace with population growth and that feed-fed production has necessarily met increases in human dietary demand for animal products. Through solutions such as moderati...Continue Reading
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