Abstract Costs and benefits derived from the introduction of cacti production into goat-production systems in the northeastern plain of Mendoza were examined by a simulation model. The model was run with 50, 100, 150, and 200 does and annual rainfall probabilities ( f) from 0.1 to 0.9. Investments and costs were derived from data recorded by the present authors through the establishment and monitoring of experimental cacti plantations. Cactus production was based on a rain-use efficiency factor of 12.5 kg DM ha −1 year −1 mm −1 and the annual rainfall probabilities in the area. The cut-and-carry management method was considered for pen feeding during 110 days (last third of pregnancy and 60-day lactation) with 3.6 kg fresh material goat −1 day −1. A decrease in goat annual mortality from 10% to 2% and an additional annual amount of kids per goat were considered as direct benefits derived from supplementing goats with spineless cactus in the fall–winter period. As a consequence of this practice, an additional 0.2 kids appears to be obtainable in field conditions. A secondary benefit was the reduction of water consumption by goats. The internal rate of return (IRR) corresponding to 0.2 kids goat −1 and the additional kids required to reach an IRR equal to the opportunity cost of capital (12%) were determined. The establishment cost of cacti plantation ranged from US$ 525 ha −1 (50-head goat herd; f0.1) to US$ 242 ha −1 (200-head goat herd; f 0.9), amounts that would be cost prohibitive for many stockmen. Cost of fence installation was the main item of establishment cost in most the analyzed scenarios. This cost may be reduced if a fence made of spiny cactus is established. If dependable rains ( f 0.8) are considered, the IRR would be lower than 12% for all goat-herd sizes, and the additional kids per goat required to reach 12% IRR would range from 0.21 to 0.29 for 200 and 50 does, respectively. Further efforts are needed to establish, under field conditions, the actual additional amount of kids that may be obtained as a consequence of supplementing goats with spineless cactus.