Diets with soybean expeller or soybean meal for finishing feedlot steers

The objective of this study was to evaluate animal performance and carcass yield of feedlot steers fed a grain-based diet including soybean expeller (SbE), soybean meal (SbM) or soybean meal with soybean oil added to meet the lipid content of SbE (SbM+oil). Each protein supplement was included at 3 dietary levels to achieve 10, 13 and 15% of CP on dry matter basis. One hundred and eighty steers (327 ± 18 kg) were distributed in 45 pens allowing for 5 pens per treatment combination and fed the treatment diets over a 102-day period. Diets contained cracked corn, millet hay, urea, a vitamin and mineral premix, and the protein concentrate under study. No interactions were detected (p≥0.16) between Diet and CP level. The CP level did not affect (p≥0.12) final body weight (BW) and average daily gain (ADG). Treatments with 10% CP resulted in lower (p≤0,03) dry matter intake (DMI) relative to BW (DMIBW). Treatments with 13 and 15% CP resulted in greater (p≤0.02) hot carcass weight and yield than 10% CP. No Diet effects were observed (p≥0.21) on final BW and AGD. DMI was greater (p<0.05) for SbE and SbM compared with SbM+oil. And DMIBW was largest for SbE, medium for SbM and lowest para SbM+oil (p≤0.02). Feed efficiency improved (p≤0.01) for SbM+oil compared with SbE and SbM. No effects of Diet were detected (p≥0.16) for hot carcass yield, carcass weight, rib eye area, and back fat thickness. We concluded that performance would be similar between animals fed SbE and SbM containing diets. Adding oil to SbM diets may improve feed efficiency by reducing feed intake. A 10% CP dietary content might be enough to sustain high feedlot performance. However, 13% CP might result in greater carcass weight and yield.

Key words: finishing beef cattle, soybean expeller, soybean meal, crude protein.

Abstract published in Revista Argentina de Producción Animal, Vol. 40, N° 1: 15-21 (2020).