The goal of this study was to find a cost that will decrease input while also improving animal performance. The project was split into two halves. Phase I included a twenty-one-day pre-experimental trial to prepare the animals for the trial without a rumen modulator. Using an in vitro gas production test, phase II was conducted for 120 days with a mixture of rumen modifiers that included neem seed powder (Azadirachta indica), fennel seed (Foeniculum vulgare), and harad (Terminalia chebula) mixed in a concentrate mixture. The amount of Rumen modifier needed was determined based on the dry matter intake of heifers. There were 21 animals in all in the trial, which was divided into three treatments. The first treatment was a control therapy without the use of a rumen modification. The second treatment used a rumen modification to increase the dry matter intake of the animals by 2%, while the third treatment used a rumen modifier to increase the dry matter intake of the animals by 4%. The treatment that included soybean straw as dry fodder, Lucerne as a green fodder, and a concentrate mixture had no significant (P> 0.05) influence on the animals' body weight gain, digestibility coefficient, or dry matter intake. Treatment two, in which seven animals were fed dry soybean straw, green lucerne, and a concentrate mixture with a herbal feed additive, rumen modifier powder, at a rate of 2% of dry matter intake, produced the greatest outcomes of all the treatments. The weight of the animals grew significantly (P0.01) by 63.45 kg, whereas the dry matter intake increased significantly (P0.01) from 6.55 to 7.15 kg. In treatment two, the digestibility coefficient shows excellent results. When compared to the control group, it increases considerably (P> 0.01) by 63.45% in treatment two. Feed cost per kg body weight gain in T1, T2 and T3 was Rs. 32.96, 27.92, 37.90, respectively which indicates the cost per kg gain of weight can be reduced by feeding rumen modifier. The cost/kg body weight gain was lowest in rumen modifier @ 2% over another concentrate feeding. However, based on the gain in body weight it can be said that there was the effect of incorporation of rumen modifier with concentrate mixture in the ration of heifer because, the total cost/kg body weight gain (Rs.) is less in T2 followed by T1 and T3 group of treatments, 195.49, 230.76 and 265.32 respectively.
