Protein Requirements for Maintenance of Thai Native Male Cattle Fed Rice Straw Based Diets

The objective of this study was to determine the protein requirement for the maintenance of male Thai native cattle. About 18 cattle with body weight of 125 +/- 4.9 kg were arranged in a randomized complete block design with 6 replications (block) and 4 treatments. Cattle were fed with dietary Crude Protein (CP) levels of 5.0, 8.0 and 11.0% CP with similar amounts of metabolizable energy. Dry matter, organic matter, crude protein and neutral detergent fiber digestibility increased (p<0.05) with increasing levels of CP. Moreover, Nitrogen (N) intake, N absorption and N retention increased (p<0.05) with increasing levels of CP. Prediction equation CP intake (g CF kg(-1) BW(0.75)) with relation to average daily gain (ADG, g kg(-1) BW(0.75)) was CF intake = 0.409 ADG + 4.22 (R(2) = 0.883, SE = 0.624, p<0.01, n = 18). From these equations, it can be explained that the CP requirement for the maintenance of male Thai native cattle is 4.22 gCP kg(-1) BW(0.75).