The present study was conducted out to evaluate Effects of straw content and its inclusion time in starter feed on the performance of Holstein dairy calves. In this experiment, 60 Holstein Dairy Calves (body weight 3 ± 39 kg) were used in a 80-day trial period (from 0 to 80 days old).. The experiment was conducted in a completely randomized design. Ih Each experimental treatment consisted of 15 calves (8 females and 7 males) experimental treatments included. 1) mash diet with feeding of 2% straw until 40 days and 4% straw to 80 days (2 mash feed with 4% straw whole time (from 0 to 80 days) 3) mash diet with feeding 4% straw until 40 days and 8% straw to 80 days 4) mash diet with feeding 8% wheat straw whole time (from 0 to 80 days). . All calves were weaned at 60 d of experiment. During the experiment, calves received 5 kg of milk a day, and had free access to fresh water and feed. Consumption dry matter, average daily gain; feed intake were calculated. Rumen fluid samples were collected via a stomach tube at d 35 and 75 of the study. The results of this study showed that dry matter intake was not affected by treatments, although, in terms of number, the amount of intake in the treatment of 2% straw half time was greater than other tratment The effect of level on average daily gain was not significant. However, the highest daily gain was related to the change in straw percentage from half of the period (treatment 1 and 3). The final weight was affected by the surface and was significantly ( P 0.05) reported in treatment that changed content of straw from 40 days of age. The digestibility of dry matter tended to be significant ( P = 0.06). The digestibility of neutral detergent fibers in the treatment of 8% forage in half and total periods compared to other treatments was significant ( P 0.05). The pH of the rumen and ammonia nitrogen was not affected by the straw level. The duration of rumination was not influenced by the level of the time. The effect of level and time of forage provision on non-nutritional behaviors tended to be significant ( P = 0.1) and was reported at lower level of straw (2% straw) . Body depth was tended to be significant r in treatments with 2% straw half time treatment.( P =0.06) . But in treatment 2 (4% of the straw of the whole time) was the lowest. . In general, using straw with changes in this experiment, had bether result. Considering the effect of the time of forage provision, it seems that mash diet with precentage changed from 40 days of age (from 4% to 8%). Has a more positive effect on calf performance. Keywords: Holstein Calf -Starter diets- Forage- level