Livestock production in tropical countries consumes significant amounts of water for cooling and washing facilities and releases large amounts of wastewater to the environment, resulting in water scarcity and pollution. However, improving water-use efficiency (WUE) at the livestock farm level has received little attention in current research. This study measures the WUE of pig farms in Vietnam, a tropical Southeast Asian country. There, livestock production consists of three farming systems: industrial farms (IFs), semi-industrial farms (SIFs), and traditional farms (TFs). This study compares the WUE of these farming systems, suggests which of the systems is most sustainable, and proposes solutions to improve the WUE of each system. The results of surveying 247 pig farms and applying data envelopment analysis show that the free use of groundwater resources causes a low average WUE of 52%. IFs (closed pigpens) have the highest WUE, followed by TFs and SIFs (open pigpens). This finding confirms the sustainability of IFs over other types of farming. Furthermore, using Tobit models, we analyze the determinants of the WUE within each farming system. The results show that shortening the fattening phase and decreasing the floor space allowance per pig increase the WUE of TFs and SIFs. In addition, decreasing the depth of the puddles in pigpens and the frequency with which these puddles are drained improve the WUE of IFs. These results suggest a need to revise the design of pigpens in order to reduce water use related to washing and cooling.
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