PRODUCTIVE AND ECONOMICAL EVALUATION OF UREA, LUPIN GRAIN, PEANUT EXPELLER AND SOYBEAN MEAL IN FATTENING RATIONS FOR BEEF HEIFERS

Abstract

The aim of this study was to evaluate animal response on diets based on pasture silage and concentrates from different protein sources for finishing beef heifers. Twenty eight spring born Hereford x A. Angus virgin heifers of 19-20 months of age and 320 kg initial live weight, were used in the experiment. A randomised complete block design with 4 treatments and 7 replicates was used. Treatments were: T1 concentrate with urea; T2 concentrate with lupine; T3 concentrate with peanut expeller and T4 concentrate with soybean. Each treatment also considered grounded barley and minerals. All treatments were formulated approximately isoproteic and isocaloric with 20.5% CP and 3.1 Mcal ME kg^-1, dry matter basis, and were fed daily to the animals at 1% of their live weight. Ryegrass was offered at discretion as a supplement. Daily live weight gains were statistically similar 1.382; 1.442; 1.364 and 1.384 kg animal^-1, respectively (P> 0,05); daily food intake was 10; 10.2; 10 and 9.9 kg DM animal^-1; feed conversion efficiency was 7.2; 7.1; 7.3 and 7.2 kg DM feed consumed kg^–1 live weight gain were obtained; carcass killing percentage were statistical similar with 52.4; 51.8; 52.0 and 53.0% (P> 0,05); a similar situation occurred for rib eye area with 59.3; 58.8; 55.6; 56.8 cm² (P> 0,05) and a pH of 5.46; 5.46; 5.49 and 5.49 (P> 0,05) for treatments 1 to 4, respectively. It is concluded that heifers fed diets containing concentrates from different protein sources s did not affect daily live weight gain and carcass results. The lowest cost diet was the one using lupine grain as a protein source in the concentrate.