GROWTH-RESPONSE OF LAMBS FED SOYBEAN STRAW TREATED WITH SODIUM-HYDROXIDE, CALCIUM HYDROXIDE, AND AMMONIUM HYDROXIDE

Forty-five Suffolk lambs (averaging 30.6 +/- 0.7 kg BW) were randomly assigned to five treatment groups with nine animals per treatment. The diets consisted of: water-treated soybean straw (SBS); NaOH-treated SBS; Ca(OH)2-treated SBS; NH4OH-treated SBS; and fescue hay (FH). The SBS was treated with the alkalis at the rate of 4% of the straw dry matter (DM) and mixed with water to a final moisture level of 65%. Straw diets were individually ensiled for at least 21 days before feeding. Animals were fed their diets free choice for 75 days following a 14-day preliminary period. Lambs fed Ca(OH)2- or NH4OH-treated SBS consumed more (P < 0.05) DM than those fed NaOH or water treatments but less (P < 0.05) than those fed FH. Crude protein consumption was higher (P < 0.05) for lambs fed FH- or NH4OH-treated SBS than for those fed the other treatments. Gross energy consumption was highest (P < 0.05) for lambs fed FH and lowest (P < 0.05) for water-treated and NaOH-treated SBS. Lambs fed FH gained weight faster (P < 0.05) than those fed water treatment. No differences (P < 0.05) were observed among treatment groups in feed/gain ratio. None of the alkali treatments resulted in significant improvement in animal performance over the water treatment. Therefore, alkali treatment may not be a practical method of making SBS a more useful feedstuff for growing lambs.