Rumen fermentation characteristics of Ongole crossbred bulls in response to different inclusion levels of dried cassava chips and palm kernel cake

This study determined the best proportion of dried cassava chips (local name: gaplek and palm kernel cake (PKC) with a fixed proportion of rice straw as assessed by rumen fermentation characteristics. Three rations were offered to 14 Ongole crossbred bulls (average liveweight at 200±20 kg). The rations were mixtures of rice straw, gaplek, and PKC at ratio of 20:70:10 (T1), 20:50:30 (T2), and 20:30:50 (T3). and 2 urea was added to each ration. Ruminal fluid samples were obtained 0 hours before feeding at week 14 to measure pH and analyze VFA, NH₃-N, and microbial N concentrations. Rumen pH was not changing (range 7.1-7.5). The T2 and T3 treatments showed lower total VFA concentrations (P<0.05) than T1 treatment (71.6 and 70.3 vs. 88.4 mM, respectively). The highest NH₃-N concentration (P<0.05) was shown by T2 and there were no significant differences between T1 and T3 treatments. The greatest microbial N concentration was shown by T3 treatment, and was followed by T2 and T1. It can be concluded that a high inclusion of gaplek caused no adverse rumen digestion characteristics. A safe combination of rice straw, gaplek, and PKC was at a proportion of 20:30:50.