Rest and deferred rotation grazing treatments have proven to be effective tools that improve range condition, but little is known about their effect on range animal’s diets. The purpose of the present research was to evaluate the impact of deferment in a short-duration grazing on vegetation and diet quality of heifer in a context of a Puna grassland ecosystem. The study was conducted under a completely randomized factorial design, where treatments resulted from the combination of two grazing systems (shorth duration grazing with and without deferment) evaluated over three years. Forage yield (4.9 vs. 4.5 Tm DM/ha/year) and range condition (55.5 vs. 50.7 %) improved with deferment. Conversely, diet quality was negatively affected (P<0.05) as result of deferment as evidenced by a lower in vitro digestibility of dry matter (40.6 vs. 45.5 %), a higher neutral detergent fiber content (79.0 vs. 74.6 %) and also a lower crude protein content (10.0 vs. 11.4%). The results revealed that deferred grazing improves range condition and forage yield of Puna grasslands when managed under a shorth duration grazing scheme; however, at the cost of reducing the quality of the diet selected by heifers. When combined with short-duration grazing, deferment improved range condition and increased forage yield at the expense of diet quality, although, with no failure to meet the minimum recommended protein level for bacteria ruminal function. تفاصيل المقالة