Mercy, A DSunil WilsonKAU2019-05-292019-05-292001http://krishikosh.egranth.ac.in/handle/1/5810105563PGAn investigation was carried out to assess the effect of energy supplementation on growth of crossbred heifers. Eighteen crossbred heifers with an average age of 15 months and were distributed into three groups as uniformly as possible with regard to age and body weight. The dietary treatments TI, T2, and T3 were randomly allotted to each group. The three dietary treatments were Tl - control diet (concentrate mixture + straw) as per ICAR recommendations, T2 - control diet supplemented with 0.5 kg ground maize and T3 - control diet supplemented with 1 kg ground maize. The animals maintained on the three dietary treatments Tl , T2 and T3 showed an average daily body weight gain of 535.47,602.15 and 631.18 g respectively during the experimental period of 155 days. Statistical analysis of the body weight gain showed no significant difference between the three dietary treatment groups. The average daily dry matter intake was significantly higher (Pin the animals maintained on T3 ration compared to Tl and 1'2. However the dry matter intake as percentage of body weight remained similar in the heifers fed the three experimental diets. The energy supplementation did not seem to have any effect on the feed to gain and protein efficiency ratios of the crossbred heifers. Energy supplementation to the crossbred heifers had no effect on any of the rumen fermentation characteristics as pH, total volatile fatty acid concentration and ammonia nitrogen concentration of the rumen liquor.• The plasma levels of calcium and phosphorus also remained similar for the animals maintained on the three dietary treatments. A significant increase in the digestibilities of dry matter (P<0.05) and crude protein (Pobserved in the animals supplemented with maize at 0.5 (12) and 1 kg (T3) levels as an energy source compared to the control (TI). However the digestibilities of ether extract, neutral detergent fibre and acid detergent fibre remained unaffected by the extra energy supplementation. An improved reproductive performance was exhibited by the animals maintained on T3 ration. The cost of feed for producing unit gain was almost similar for the three dietary treatments. Thus a critical assessment of the overall results obtained during the course of the present study did not reveal any significant effect of energy supplementation on the growth, feed efficiency, rumen fermentation characteristics and the plasma levels of calcium and phosphorus. However, energy supplementation improved the dry matter and crude protein digestibilities. The reproductive performance of the animals was also better in the high energy supplemented group.ennullThesis