Studies were conducted on two calves and a pregnant female captured from the forest to assess the feed utilization, growth pattern and milk composition in Mithun (Bos frontalis), a rare bovine species of north-eastern India. The DMI, kg/100 kg body weight was 0.05 with DM and OM digestibility of 56.95 ± 3.68 and 58.46 ± 3.51 percents, respectively, in calves. The growth was more during the May to October months, however, the average growth of 181.26 ± 23.51 g day-1 was obtained during the year on grazing. The Mithun was not a milk yielder, but became accustomed to milking. Fat content in milk varied from 6.8 to 7.8%. The total solids, protein, lactose, ash and solid not fat (SNF) were estimated at 18.0, 4.9, 5.0, 0.8 and 10.7% respectively with COB negative at 4°C. The birth weight of the male calf was estimated at 22.0 kg, and an average growth of 325.14 g day-1 was determined in 214 days with maximum weight gain during the first two months of age.