Feed Intake, Nutrient Digestion, Growth and Reproductive Performances of Boran-Friesian Cross Breed Dairy Heifers Through Different Wheat Straw to Concentrate Feeds

This study was conducted to examine the effect of different wheat straw and concentrate proportions on feed intake, nutrient digestibility, growth and reproductive performances of F1 cross breed (Boran X Friesian) dairy heifers. Wheat straw (WS) with 93% dry matter content was chopped (3-5 cm in length) and mixed with concentrate, molasses and water. The amount of water used for the preparation of total mixed ration was three fold of the molasses amount. Twelve dairy heifers (90.45 ± 7.37 kg LW, mean ±S.D) were randomly assigned to one of the three dietary treatments (WS80= 80% WS: 20% concentrate; WS60 = 60% WS: 40% concentrate) and WS40 = (40% WS: 60% concentrate) in a completely randomized block design. The diets were offered ad-libitum and allowing 15-20% refusal. The experiment was consisted of 345 days of feeding trial and 7 days for the measurement of digestibility. Different wheat straw and concentrate proportion had no significant effect on organic matter intake of dairy heifers. In contrast, dry matter (DM), crude protein (CP) and acid detergent fiber (ADF) and neutral detergent fiber (NDF) intakes were greater when the heifers were fed WS40 versus the other treatments. The greater (P<0.001) DM, CP, ADF and NDF digestibility, feed conversion efficiency and growth rate were observed in WS40 than the other treatments. The greater (P<0.001) body weight at first service for dairy heifers was perceived in WS80 than the other dietary treatments. Conversely, the smallest age at first service, age at first conception and number of service per conception for dairy heifers was noticed in WS40 than the other dietary treatments. Raising dairy heifers by using 40% wheat straw and 60% concentrate can be recommended for practical application.