Pilot plant production of sulphur dioxide-treated mesquite wood. II. Digestibility and feedlot performance by lambs

Abstract

The effects of sulphur dioxide (SO 2) treatment of ground mesquite ( Prosopis glandulosa) on apparent digestibility, nitrogen retention and animal growth were studied in 3 experiments with growing lambs. In Experiment 1, a complete diet was given in which ground mesquite (GM), either untreated or SO 2 treated, comprised 0, 10 or 20% of the total diet. Apparent organic matter digestibility (OMD) was lower ( P < 0.01) for all diets containing GM than for the control. Diets containing untreated or SO 2-treated GM did not differ in digestibility. Nitrogen retention was similar with all treatments. In Experiment 2, a complete diet contained either 0, 10, 20 or 40% SO 2-treated GM or 40% untreated GM. OMD of diets containing 10% SO 2-treated GM was similar to that of the control. All other diets containing GM were lower ( P < 0.01) in OMD than the control. Diets containing 40% SO 2-treated GM had lower ( P < 0.01) OMD than diets containing 40% untreated GM. In Experiment 3, daily gains and gain: feed ratio by lambs fed on a basal diet with 5, 10 or 20% SO 2-treated GM substituted for cottonseed hulls were similar to the control.