The performance of liverstock is largely affected by their level of energy intake. To increase milk quantity and quality energy dense ingredient i.e "By Pass Fat" (priplus prime manufactured by UNICHEMA. Pvt, Australia was included in the ration of dairy animals to determine its effect on the productive performance of indigenous cross-bred dairy lactating cattle.

For this purpose 12 cross bread (Freisian x Sahiwal) cows in early lactation period, of almost similar lactation number, milk production and body weight were randomly selected and divided into three group (A, B & C) comprising of 4 animals each.

Three concentrates were prepared in such a way to have 16% C.P & 1.37 Mcal/Kg M.E Concentrate I was taken as control. 10% "By Pass Fat" was incorporated in concentrate II which was isocalorics & isonitrogenous to concentrate I and 500gm "By Pass Fat" per animal per day along with concentrate I was supplemented in ration Ill. These three concentrate I, II & Ill were fed to the animals of group A, B & C respectively.

The average total milk production of the animals of groups A, B & C fed rations I, II & Ill were recorded 4478.79, 4663.42 & 4663.39 litter respectively, where as the average total feed consumed by the animals of group A, B & C was 13307, 13121 & 13128.5 Kg. respectively.

The best feed efficiency (2.81) of animals of groups B & C fed rations II & Ill, where as the poor feed utilization (2.97) was observed in the animal of control group (A). The average total weight gained by the animals of groups A, B & C fed rations I, II & Ill were 43, 54 & 89 Kg. respectively.

The results thus obtained showed significant (P < 0.05) improvement in the weight gain, milk production, feed consumption and feed efficiency of the animals of groups B and C fed ration II (10% "By Pass Fat") and ration Ill (additional supplementary feeding of 500 gms by pass fat) as compared to the animals of group A fed ration I (control).

However, there was non significant difference in the milk production, weight gain & feed utilization of the animals of group B & C fed ration II & Ill containing 10% "By Pass Fat" and 500gm additional supplementary feeding of "By Pass Fat" over above recomended nutrient requirements in the ration of dairy cattle. The data an milk composition showed nonsignificant effect in the milk of the animals fed different experimental rations.

There was 4% increase in the milk production of the animals fed ration containing 10% "By Pass Fat" as compared to the milk production of the animals fed ration containing no "By Pass Fat". -

Possibly this might be because of lower genetic potential of the animals.

Therefore "By Pass Fat" proved better source of energy as compared to Carbonecious ingredinets.

An additional supplementary feeding of 500 gm "By Pass Fat" over & above the recommended nutrient requirement in the rations of dairy animals did not show any increase in the milk production of the animals.