Lupin silage and lupin seeds in beef cattle rations

The effects of harvest date on ensiling characteristics and nutrient yield per hectare were evaluated for lupin (Lupinus albus), lupin-oat and oat (Avena sativa) crops. Growth performance, carcass merits and feed intakes were evaluated for both lupin silage and raw and roasted lupin seeds in two steer feeding trials.

The lupin silages had a lactate-type fermentation with low pH and high lactic acid contents. Crude protein (CP) content decreased from 19.1% at the second pod stage to 16.7% at senescence. Lupin-oat silages had higher dry matter (DM) content 28.9, 29.7 and 65.5% compared to lupin 20.5, 20.8 and 47.0% at each harvest date, with shorter drying times.

The lupin silage had a lactic acid fermentation with lower DM, neutral detergent fiber (NDF) and protein nitrogen content than the grass silage but higher CP. There were no statistically significant differences in gain, carcass weight, dressing percentage or backfat levels between steers fed lupin or grass silage. Dry matter intake of the silages was not significantly different but there was a tendency for lower DM intake of lupin silage when supplemented with potatoes.

Twenty-eight Charolais-cross steers (235 $\pm$ 35 kg) were fed grass silage only (SIL, n = 7) or silage plus supplements fed to supply CP at 6.5% of the silage DM intake from raw lupin (RL, n = 7), roasted lupin (ROL, n = 7) or soybean meal (SBM, n = 6). In the growing phase, steers fed RL, ROL or SBM had daily gains significantly higher (P $<$ 0.05) than steers fed SIL. Steers fed the SBM diet had significantly higher daily gains than RL, with steers fed ROL being intermediate. Silage DM intake was significantly lower on RL and ROL supplemented diets compared to SIL. (Abstract shortened by UMI.).