Growth and Fattening Performances of Friesian-Boran Crossbred Bull Calves Fed on Different Protein Supplements

The study was conducted at Holetta Research Center to evaluate growth performance and economic feasibility of fattening 50 and 75% Friesian-Boran growing crossbred bull calves for the period of 626 days. Twenty-four 50% Frisian-Boran crossbred weaned male calves and another twenty- four 75% Frisian-Boran crossbred growing weaned calves reared at Holetta Research Center were randomly assigned to six dietary treatments; T1=Noug seed cake based supplement with 18% CP level, T2=Noug seed cake based supplement with 20% CP level, T3= Linseed cake based supplement with 18% CP level, T4= Linseed cake based supplement with 20% CP Level, T5=Cottonseed cake based supplement with 18% CP and T6=Cottonseed cake based supplement with 20% CP Level. The interaction effect between feed supplements and calf genotypes was not significant. In this study higher (p<0.05) body weight of 196.50±7.78 and 404.88±17.96 kg was attained for 12 and 24-months growing bull calves that were supplemented with cotton seed cake at 20% crude protein level, respectively than calves supplemented with 18% CP level. Crossbred bull calves supplemented with cotton seed cake at 20% CP had also higher (p<0.05) final body weight, live weight change, daily weight gains and feed conversion efficiencies of 404.88±17.96, 334.25±17.62, 0.558±0.03 kg and 9.46±0.87 kg DMI/kg gain, respectively than those fed on noug seed cake at 18% CP level (314.25±17.96, 244.25±17.62, 0.407±0.03 kg and 13.60±0.88 DMI/kg gain), respectively. Except for initial weight, i.e., weaning weight and feed conversion efficiencies, Friesian-Boran (50% FB) crossbred growing bull calves had better (p<0.05) final body weight, live weight change and daily weight gain of 378.04±17.96, 308.79±10.17 and 0.518± 0.02, respectively compared to those with 75% exotic blood level (346.25±10.37, 275.38±10.17, and 0.463.02) respectively. Friesian Boran (50% FB) crossbred growing bull calves fed on cotton seed cake-based supplement with 20% CP level (T6) had better net income of 10792.7 ETB/head followed by those supplemented with linseed cake with 20% CP level (T4) which was 5772.6 ETB/head. Generally, dairy producers (farmers) can benefit from fattening of their crossbred dairy bull calves; especially 50% Friesian-Boran crosses using Cotton and linseed cakes-based concentrates formulated with 20% crude protein.