This paper examines the role of cattle production in the evolution of smallholder farming systems in a frontier region of Brazilian Amazonia. There are many incentives for smallholders to raise cattle, but the success of cattle enterprises depends on a number of factors, both endogenous and exogenous to individual farms. A key factor in the intensification of cattle production is pasture management. We identify three models of pasture management, reflecting different levels of specialisation and intensification of production systems. Contrary to conventional wisdom, our findings indicate that pasture quality and degradation are related to under-utilisation and low stocking rates. This suggests that more intensive systems may be more ecologically sustainable in some contexts. However sustainable intensification strategies, which could potentially contribute to frontier stabilisation, depend on investment in infrastructure, markets and social capital beyond the capacity of individual farms or farmers. Español