Energy Balance Studies in Holstein Friesian and HF X Hariana Calves Fed on Wheat Straw Based Ration

Nine growing mule calves were divided into 3 groups of 3 each. Group T₁ comprised of pure Holstein Friesian and group T₂ and T₃ crossbred (HF x Hariana) calves. The animals in group T₁ and T₂ were offered concentrate mixture and wheat straw based ration to provide recommended levels of nutrients, whereas those in group T₃ received similar ration but provided 75% of the energy requirements. Metabolism trial on all animals was conducted after feeding them for about 3 m, was followed by respiration chamber studies. The DM intake was 101.3±6.05, 102.4±2.02 and 78.1±2.66 g/kg w^0.75/d in groups T₁ T₂ and T₃, respectively. Digestibility of DM was significantly (P<0.05) higher in purebred animals (T₁) as compared to crosshreds (T₂) at the same energy level. The dietary energy level on straw based diet had no significant effect on the digestibility of nutrients. DOP intake/kg W^0.75/d was 8.96±0.24, 8.42±2.09 and 7.28±0.33 g in the groups T₁ T₂ and T₃, respectively. Nitrogen balance was positive in all the 3 groups but was significantly lower in group T than those in the other two groups. ME intake/kg W^0.75/d in three groups was 260.5±17.11, 248.4±2.03 and 174.9±9.91 Kcals, respectively. It was also higher (P<0.05) in group T₁ and T₂ as compared to group T₃, There was no significant difference in total heat prodaction among the animals in 3 groups. Methane production was 196.4 177.0 and 116.3/1 in the 3 respective groups. Losses through methane energy as % of GE in the 3 respective groups were 7.12. 5.69 and 5.15. Enemy balance was positive in ail the 3 groups and it ranged between 44.08 to 107.3 Kcals/kg w^0.75/d. On the basis of the study it is, hence recommended that ME requirement for growing calves fed on stravv based diets should not be reduced.