In this article, Cahyadi et al. present the findings of a study on herd dynamics of smallholder cattle producers in the two major agro-ecosystems (irrigated lowland and rain-fed upland) in East Java. The research aims to better understand the capacity of smallholder cattle producers in order to increase their production and income in line with government targets. A total of 184 farmers participated in the study in 2010. Their cattle were monitored on a monthly basis to record vital statistics, as well as transfer and sales-related data.