EVALUATION OF TWO LEVELS OF UREA ON A SALT-MINERAL MIXTURE AD LIBITUM OF PROTEIN FOR STEERS.

Abstract

An experiment was carried out to study the effect of urea supplied throught a mineralized salt mix on the performance of Zebu steers. Two mixes of mineralized salt were prepared based on 25% (T25) or 50% (T50) urea, row salt and 20% bond meal. These mixes were supplied ad libitum to steers in feed lot based on Brachiaria humidicola hay. The T25 mix intake was greater (P<0.10) than the T50 mix intake, 263 and 151 g/animal/d, respectively. Raw salt intake was greater (P<0.10) on the T25; however, the urea and hay intake were not different (P>0.15) between treatments. Similar weight gain (P>0.15) was obtained, 298 and 255 g/animal/d with the T25 and T50, respectively. Average crude protein intake was 358 g/animal/d which only represent 67% of the requeriments for maintenance and weight gain of steers; that suggests a physiological change at ruminal level which improved the utilization of available nitrogen. The individual daily cost of mixes intake was B/ 0.050 and B/ 0.034 for T25 and T50, respectively. It is concluded, that mixes based on raw salt and bond meal are a practical and economical way to supply urea to steers under the conditions of this study.