Effect of Low Energy Followed by High Energy Based Total Mixed Diets on Growth Rate, Blood Haematology and Nutrient Digestibility in Growing Buffalo Heifers

Twenty-two buffalo heifers, 6-8 months old, 98.57 +/- 5 kg average body weight were divided into two groups and randomly assigned either control diet for the duration of the experiment which contained 2.55 Mcal/kg of DM (as per NRC, 2001 recommendations of Holstein heifers) or a stair-step diet which contained 2.03 Mcal/kg of DM (80% ME of control-SLE) fed for 120 days followed by 3.01 Mcal/kg of DM (120% ME of control-SHE) for 60 days. Heifers on SLE diet gained (p<0.05) less weight (0.51 vs. 0.60 kg/day) but on SHE diet, gained significantly (p<0.01) more weight (0.82 vs. 0.58 kg/day) respectively, compared to heifers fed the control diet. Heifers on the SLE diet have poorer FCR (6.73 vs 5.72) but with SHE diet have better (p<0.01) FCR (5.23 vs 7.41) compared to control, respectively. Daily DM consumption for the entire feeding period was similar in both groups but heifers reared on stair-step scheme gained 1.67% higher weights than control. Blood was collected on 0, 120 and 180 days of the experiment and showed that all haematological values increased with the advancement of age, with the exception of lymphocyte percentage; however, these values were not affected by dietary treatment. Apparent digestibility of DM, OM and CP remained unchanged on both the SLE and SHE diets, respectively, compared to the control. However, NDF and ADF digestibility increased (p<0.05) with the SLE diet but decreased with the SHE diet compared to control diet, respectively. Nitrogen retention was not affected in heifers fed either the SLE or SHE diets compared to the control (p>0.05). Feed costs per kg gain of heifers fed stair-step diets were 16.57% less than those fed the control diet.