Effect of replacing concentrates with cassava root-top silage on feed utilization, rumen fermentation, blood parameters and growth performance in beef cattle

Objective: This experiment aimed to evaluate the effects of replacing concentrates with cassava root-top silage (CARTOS) on feed intake, digestibility, rumen fermentation, blood parameters, and growth performance of beef cattle. Methods: : Twenty crossbred bulls with a body weight (BW) of 226 +/- 56 kg were randomly assigned to one of five treatments for 90 days in a randomized complete block design (RCBD) having four blocks based on BW. The concentrates were replaced by CARTOS at levels of 0, 25, 50, 75, and 100% DM. Animals were fed dietary treatments at 1.8% BW, with rice straw offered ad libitum. Results: : The dry matter (DM) and crude protein (CP) intake were decreased (p<0.01, p=0.04) when the diet's CARTOS level was increased. The digestibility of DM, OM, and CP were not different among treatments, while fiber digestibility was increased with the inclusion of CARTOS (p=0.03). The addition of CARTOS to replace concentrates did not change ruminal pH or volatile fatty acid (VFA) proportions except for acetic acid, which increased with the addition of CARTOS (p=0.03). The ruminal ammonia-nitrogen (NH3-N) was decreased (p<0.01) with increasing levels of CARTOS. The blood glucose and blood urea nitrogen (BUN) decreased (p=0.01) with the addition of CARTOS at 100%, whereas total protein and hematological parameters did not change with increasing levels of CARTOS. The use of CARTOS to substitute concentrates at 75 and 100% decreased average daily gain (ADG) and gain to feed ratio (G:F) (p<0.01); therefore, the addition of CARTOS up to 50% maintained ADG and G:F in beef cattle. Conclusion: : The CARTOS can be replaced for concentrates up to 50% in beef cattle without adversely affecting feed intake, nutrient digestibility, rumen fermentation characteristics, blood parameters, or growth performance of beef cattle.