The objective of this study was to evaluate the effect of the supply of L. perennial grass and Altoandina oat silage variety on the productivity of lactating cows, in the upper tropics of Narino-Colombia. 12 F1 cows (Kiwi cross x Holstein) were used, in a replicated Latin square design (2 x 2), and with two treatments (T), corresponding to silage offers: T1: 20% and T2: 35% on consumption of total dry matter (CMST). Periods of 12 days, 7 of accustoming and 5 of measurement were evaluated. CMS and milk production (PL) were estimated, and samples were collected to determine fat, protein, total solids and urea nitrogen in milk (MUN-mg / dL); Blood sample was also taken by determining serum metabolic profile indicators (Glucose-Cholesterol-BUM (Blood urea nitrogen) -mmol / L). The information was processed with analysis of variance and means comparison tests (Tukey <0.05). There was a significant effect (p <0.05) for the variables: Silage CMS, higher for T2: 2.78 vs. T1: 1.35 (kg / MS / cow / day), the PL was higher for T2: 14 , 9 vs. T1: 14.3 L / cow / day, and the higher MUN and BUN for T1: 15.79 and 3.1 vs. T2: 14.46 and 2.8 respectively. It is concluded that Altoandina oat silage allowed to maintain and increase milk production (6% more), when the supply of L. perennial was replaced by inclusions of 35% silage. This new variety of oats could become an important food resource in the dairy systems of the high tropics in Colombia, for which more results with animal response, including new management, pastures and animal biotypes, need to be validated.