Ten prepubertal indigenous heifers of Assam aged 20 to 24 months were taken in the present study to induce puberty and were treated with “Crestar” ear implant, “Crestar” injection and “Folligon”. Another ten heifers of similar age and body weight were placed in control group. All the treated heifers were induced to oestrus after 29.10±0.90 hr of implant removar. However, none of the control heifers exhibited oestrus till 120 days, the period of study. The mean duration of induced oestrus was 67.50±1.44 hr, the percentage of ovulation being 70.00. Subsequently, all the heifers of the treatment group (100%) exhibited first natural oestrus with cyclic period of 22.00±0.86 days and oestrus duration of 23.60±3.84 hr with ovulation occurring in 50% animals. Eight out of 10 (80%) heifers of the treatment group exhibited second natural oestrus with cycle length of 28.75±3.03 days, duration of oestrus being 29.50±3.30 hrand ovulatory percentage of 87.50. The animals that exhibited second natural oestrus were mated and 5 (62.5%) animals conceived; while two heifers of the treated group became anoestrous and remaining 3 heifers resumed cyclicity.