EFFECT OF FEEDING NAPIER GRASS, LUCERNE AND SWEET-POTATO VINES AS SOLE DIETS TO DAIRY HEIFERS ON NUTRIENT INTAKE, WEIGHT-GAIN AND RUMEN DEGRADATION

Two experiments were conducted to assess the nutrient intake, weight g ain (ADG) and rumen degradation of napier grass (NG), lucerne (L) and sweet potato vines (SPV) fed to growing dairy heifers. In the first ex periment, 33 Friesian heifers were randomly allocated to the three tre atments namely; napier grass, lucerne and sweet potato vines which wer e fed for 104 days. In the second experiment, degradability of the thr ee diets was estimated using nylon bags incubated in two rumen fistula ted steers. The mean chemical composition of the forages were: dry mat ter (DM) 155, 807 and 123 g kg(-1); organic matter (OM), 796, 854 and 852 g kg(-1) DM; crude protein (CP), 118, 167 and 135 g kg(-1) DM and neutral detergent fibre (NDF), 587, 408 and 506 g kg(-1) DM for NG, L and SPV, respectively. The mean daily DM intake was 5.0, 5.5, and 4.2 kg while the CP intake was 0.59, 0.96 and 0.57 g for diets NG, L and S PV (P < 0.05). The ADG from NG, L and SPV were 0.50, 0.67 and 0.50 kg day(-1), respectively. The SPV diet showed higher effective degradabil ity than L and NG (P < 0.05), while the latter two forages were not si gnificantly different (P > 0.05). It was concluded from the study that NG, L and SPV contained nutrient levels that would sustain acceptable growth in heifers. (C) 1998 Elsevier Science B.V.