Through a case study from Nagchu, the Tibet Autonomous Region, China, this paper deconstructs the cattle complex theory in the context of Tibetan pastoralism. Specifically, it demonstrates that it is desirable for Tibetan pastoralists to have a larger herd size for three overlapping reasons that do not follow the logic of the cattle complex theory. First, owing to biological, cultural and economic factors, herd sizes are not equivalent to actual livestock available for production. Second, pastoralists desire a larger herd size as a long-term strategy for livelihood security and flexibility. Third, pastoralists desire a larger herd size as a means to improve their standard of living. This paper also points out that in practice pastoralists' maximum herd size is a function of labour power, rangeland area and conditions and economic status.