Supplementation of graded levels of Desmodium intortum hay to sheep feeding on maize stover harvested at three stages of maturity : 1. Feed intake, digestibility and body weight change

Abstract

Feed intake, digestibility and body weight change of lambs fed basal diets of maize stover harvested at three stages of maturity and supplemented with graded levels (0, 150, 300 and 450 g per head per day) of desmodium ( Desmodium intortum cv. Greenleaf) hay were studied. The maize stovers were harvested at 30, 22 and 12% grain moisture content which were designated as stages I, II and III, respectively. The crude protein (CP) content of the stovers showed a decreasing trend whereas the fibre contents showed an increase from stages I to III. The desmodium hay had higher CP, phenolic compounds, calcium, sulphur and manganese contents and lower fibre (neutral and acid detergent fibres, cellulose and hemicellulose) contents than the stovers. Maize stover, total dry matter (DM) and organic matter (OM) intake showed a decreasing trend ( p>0.05) with increasing stage of maturity of the stover. The CP intake was significantly higher ( p<0.05) in sheep fed maize stover harvested at stage I than at stages II and III. Total DM, OM and CP intake increased whereas maize stover DM intake showed a significant decrease ( p<0.05) with increasing level of supplementation. Desmodium hay constituted about 28, 47 and 66% of the total DM intake and, on average, there was a substitution of about 12, 21 and 37% of the stover by the desmodium hay at 150, 300 and 450 g of supplementation, respectively. Dry matter, OM and neutral detergent fibre (NDF) digestibilities showed a decreasing trend ( p>0.05) with increasing stage of maturity. Crude protein digestibility and the intakes of digestible OM and metabolizable energy (ME) were significantly higher ( p<0.05) in sheep feeding on maize stover harvested at stage I than stage III and showed a general declining trend with increasing stage of maturity of the stover. Supplementation resulted in improved digestibility of the diet. There was a significant increase ( p<0.05) in CP digestibility, digestible OM intake, digestible organic matter in the DM (DOMD), ME concentration of the diet and ME intake with increasing level of supplementation. The body weight gain showed a significant increase ( p<0.05) with increasing level of supplementation whereas all sheep without supplement lost body weight. The weight loss increased with increasing stage of maturity of the stover. Considering DM intake and digestibility, 300 g of desmodium hay appears to be an optimum level of supplementation, under similar conditions to the current study.