Growth response of post weaned F1 Friesian × Borena (Bos taurus × Bos indicus) crossbred growing heifers fed on wheat straw-based densified complete feed block.

This experiment was designed to investigate the effect of feeding wheat-straw based densified complete feed block (DCFB) on daily weight gain, feed intake, digestibility and feed conversion rate in growing heifer calves. Eight weaned F1 Frisian*Borena (Bos taurus × Bos indicus) crossbred calves (92.5 ± 27.5 kg body weight) and 5 months of age were randomly distributed into four groups, each with two animals evaluated under 4 × 4 double Latin Square Design for 240 days. The control treatment was natural pasture hay (NPH) and concentrate mix (CM) fed conventionally in a way that covers 50:50% requirements on dry matter (DM) bases and DCFB prepared by mixing wheat straw (WS) to concentrates mixture in the ratio of 50:50 (T2), 40:60 (T3) and 30:70 (T4), respectively. Each heifer group was fed on each diet for 60 days. At the end of each period the last 7 days were used to collect feed and feacal samples. However, the heifers were weighed each 15 days to estimate daily growth performances. It was found that significant (P < 0.05) differences among groups in average daily gain, feed conversion rate, feed intake and digestibility. The densification of WS and feeding in the form of feed block generally improved feed DM and nutrient intake and digestibility. The increase in the proportion of CM in the DCFBs also increased the DM and nutrient intake and digestibility. Heifer growth rate was higher (P < 0.05) in T1, T3 and T4 diets than T2 groups. Feed conversion ratio was higher (P < 0.05) both in T3 and T4 compared to T1 and T2. The total cost of production per each gram body weight gained was recorded higher (P < 0.05) for calves in the T2 group compared to calves in T1, T3 and T4. In conclusion, maintaining post weaned F1 heifer calves on DCFB composed of wheat straw and a commercial calf's concentrate based diet in the ratio of 40 to 60 would both biologically and economically feasible.