Effect of Energy and Protein Contents of Dietary Having the Same Synchrony Index on Local Beef Cattle Performance

Abstract

Macronutrients such as energy and protein affect rumen microbial growth and efficiency of microbial protein synthesis which can be increased by synchronizing energy and N-protein released in the rumen. The experiments were conducted to study the optimum energy and protein content of diet that were synchronized in releasing energy and N-protein in the rumen of native beef cattle. Randomized block design with a factorial of 3 x 2 was used in this experiment. The first factor was three diferent crude protein (CP) levels i.e. 10, 12, and 14 %; the second factor was two deferent levels of TDN (total digestible nutrients) (65 and 70 %). Eighteen local cattles were arranged into three groups on the basis of average body weight of the animals. Each group was fed six types of diet that was different in levels of CP or TDN. The diets had the same synchrony index, namely 0.560. The results showed that, with the exception of crude fat digestion, there was no effects of interaction between protein and energy on variables measured. Compared to diet with 70% TDN, diet with 65% TDN produced higher rumen microbial N, consumption and digestion of nutrients, and N retention (P<0.05). Diet with protein level of 12% tend to have better allantoin concentration in the urine, consumption and digestion of nutrients, N retention and blood urea nitrogen (BUN) than that of 10% or 14%. It can be concluded that the diet having 65% TDN and 12% protein with synchrony index of 0.560 generate more efficient N synthesis of rumen microbes and average daily gain of local cattle.