INFLUENCE OF FEEDING DIFFERENT LEVELS OF SOYBEAN MEAL IN GROWING FRIESIAN CALVES RATIONS ON: 2- PRODUCTIVE PERFORMANCE IN FINISHING PHASE.

Fifteen male Friesian calves with average body weight of 270 + 24 kg and 13.3 + 0.94 month of age were used in this study. Calves were distributed into three groups similar in number. The experimental rations were formulated as follows: ration 1 (R1): 82% concentrate feed mixture (CFM)+18 % clover hay (CH) (control), ration 2 (R2): 76% CFM+5% soybean meal (SBM)+19% CH and ration 3 (R3): 73% CFM+10% SBM+17% CH.
Replacement of CFM by SBM resulted in increasing the CP% from 14% for R1 to 15.4 and 17% for R2 and R3 rations, respectively. Digestibility coefficients  of DM, CF, NFE, NDF, ADF, cellulose and NFC were significantly higher (p < 0.05)  for R2 ration than feeding R3, while there were no significant differences between R2 and R1 were observed, except for CF and NDF which were higher (p < 0.05) when feeding on R2 than R1. The TDN%  was higher (p < 0.05) with feeding R2 than R3, while there was no significant difference between R1 and R2 or R1 and R3 was noticed. The DCP% was higher (p < 0.05) when feeding R1 or R2 than R3.  The CPI g/ME Mcal was higher (p < 0.05) when animals were fed on R3 than on R1 or R2 (55.24, 59.17 and 68.70% for R1, R2 and R3, respectively). The TDN: CP ratio was higher (p < 0.05) when feeding on R1 than R2 or R3.
The mean values of ruminal pH, VFA and NH3-N were significantly affected (p < 0.05) by the different diatery treatments. The concentration of urea-N in blood serum was higher (p < 0.05) for calves fed R2 or R3 than R1.
The ADG were 1.01, 0.98 and 1.00 kg/d for calves fed on rations R1, R2 and R3 respectively. The production efficiency was higher when feeding on R1 than feeding on R2 or R3 (36.7, 34.3 and 35.5%, respectively), and the economic efficiency, was higher when feeding on R1 than feeding on R2 or R3 being 40.13, 35.29 and 26.15% respectively.     
In general, the data indicated that feeding ration at a level 14.0% CP (% DM basis) for growing Friesian calves was successfully and economically improved animals performance compared with rations which are high in CP levels.