Dietary Crude Protein Requirement for the Growth of Young Donggala Bulls

Abstract Donggala ( Bos indicus ) bulls with specific characteristics were given recognition as a new native breed by the Central Government of Indonesia in 2014. Therefore, this study aimed to determine the minimum dietary crude protein (CP) for maximum growth of young Donggala bulls. A randomized complete block design was used, including 20 young Donggala bulls of initial body weight (BW) 165.53±3.55 kg. Furthermore, the treatment consisted of 5 dietary CP levels, namely 12, 14, 16, 18, and 20%, which were all repeated 4 times. The experimental animals were fed with elephant grass and mixed concentrate of 25 and 75%, respectively, from the total diet allocated at 2.5% BW/day. Metabolizable energy (ME) for all dietary treatments was fixed at 11.53-11.67 MJ/kg dry matter (DM), and the adaptation and measurement experiments lasted for 2 and 8 weeks, respectively. The results showed that CP intake from 12, 14, 16, 18, and 20% CP levels was 10.85, 12.73, 14.86, 17.00, and 19.12%, respectively. Organic matter digestibility (OMD), average daily gain (ADG), change in chest girth, and body condition score (BCS) of the 14.86% CP intake group were higher (P<0.05) than the values obtained for both 10.85 and 12.73% groups. However, no significant differences (P>0.05) were observed with higher than 14.86% of CP intake. There was no significant effect (P>0.05) recorded on change in wither height and body length of bulls fed different CP levels. In conclusion, the minimum CP level for achieving optimal growth performance of Donggala bulls was 14.86% of the diet.