The global livestock system puts increasing pressures on ecosystems. Studies analyzing the ecological impacts of livestock supply chains often explain this pressure by the increasing demand for animal products. Food regime theory proposes a more nuanced perspective: it explains livestock-related pressures on ecosystems by systemic changes along the supply chains of feed and animal products, notably the liberalization of agricultural trade. This study proposes a framework supporting empirical analyses of such claims by differentiating several steps of livestock supply chains. We reconstructed “trilateral” livestock supply chains linking feed production, livestock farming, and final consumption, based on the global flows of 161 feed and 13 animal products between 222 countries from 1986 to 2013. We used the embodied Human Appropriation of Net Primary Production (eHANPP) indicator to quantify pressures on ecosystems linked to these trilateral livestock supply chains. We find that livestock induced 65 % of agriculture's pressure on ecosystems, mostly through cattle grazing. Between 1986 and 2013, the fraction of livestock-related eHANPP that was traded internationally doubled from 7.1 % to 15.6 %. eHANPP related to the trade of feed was mostly linked to soybean imported for pig meat production, whereas eHANPP associated to traded animal products was mostly linked to cattle meat. eHANPP of traded animal products was lower but increased faster than eHANPP of feed trade. eHANPP was highest at the feed production level in South and North America, and at the consumption level in Eastern Asia. In Northern Asia and Eastern Europe, eHANPP was lowest at the animal products production level. In Western Europe, he eHANPP was equal at the animal products production and consumption levels. Our findings suggest that options to reduce livestock's pressures on ecosystems exist at all levels of the supply chain, especially by reducing the production and consumption in high-consuming countries and regulating international supply chains