High costs from external inputs in small-scale dairy systems (SSDS) and possible effects of climate change, require forage alternatives as silage for the dry season, from small-grain cereals that have short cropping cycles, winter hardiness, and good nutritional quality. The objective was to assess the provision of 10 kg dry matter (DM) cow^-1 d^-1 of barley (BLY) or black oat (BKO) silages in three treatments: T1 = 100% BLY; T2 = 50% BLY + 50% BKO; T3 = 100% BKO for milking cows. All treatments also received 4.6 kg DM cow^-1 d^-1 of concentrates and access to pasture. Nine Holstein cows in groups of three were randomly assigned to a 3 × 3 Latin square design repeated three times, with 14 d experimental periods. Measurements of animal variables and sampling for chemical analyses of feeds were done during the last 4 d of each period. Feeding costs were by partial budgets. There were no differences (P > 0.05) for milk yield, milk fat and protein content, milk urea nitrogen, body condition score, or live weight. The cost of BLY silage was 8% less than BKO silage. T1 had the higher margin over cost of feeds followed by T2. Both silages alone or in combination are viable options for SSDS, as there were no differences in performance, or in feeding costs or margins.