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I. Alkali (sodium hydroxide)-treated wheat straw was given to six rumen-and abomasal-cannulated sheep to study the rumen degradation of cotton-seed meal (CSM) and barley (B), and the effects of these supplements on nitrogen retention and efficiency of bacterial protein synthesis were measured.2. N degradation, using porous synthetic (nylon) bags incubated within the rumen (P), and in vivo measurement determined from the abomasal flow of N (4, distinguished quantitatively between the two supplements. Estimates of P, corrected for fractional outflow rates/h (FOR), underestimated estimates of V when FOR of undegraded protein from the rumen ( k ) of 0.05 and 0.08 were used. Estimates of V for CSM and B were 70.9 and 80.8% respectively. 3. Intakes of alkali-treated straw were not affected by the supplements. Intakes of digestible organic matter (DOM) for the diets comprising alkali-treated straw alone (W), straw plus CSM (WC) and straw plus barley (We) were 477, 575 and 590 g/d respectively ( P < 0.05) and organic matter (OM) apparently digested in the rumen (OMADR) was 339, 399 and 435 g/d respectively ( P < 0.05).4. On W, WC and WB respectively, flows at the abomasum were 11.0, 14.0 and 13.3 g/d for bacterial N ( P < 0.05) and 0,2.8 and 0.5 g/d for dietary supplemental N ; g bacterial N/kg OMADR were 32.4,35.6 and 30.9 ( P > 0.05) and N balances were 2.37, 4.27 and 3.29 g/d (P < 0.05) on the respective treatments. It was suggested that supplements increased total OM intake as a result of increased OM digested in the rumen rather than OM flow from the rumen.

Assessment of the preference of sheep for fresh, dried or ensiled forms of mucuna (Mucuna pruriens var utilis) forage was followed by investigations into the effect of supplementing straw-based diets with the forage. Four sheep were offered fresh, dried and ensiled forms of the forage in a cafeteria style to assess their preference. In the second experiment, 20 sheep were randomly assigned to four dietary treatments, namely, alkali-treated straw only (M0), treated straw supplemented with mucuna forage at 0.3% (M10), 0.6% (M20) or 0.75% (M25) of body weight (approximately 10%, 20% and 25%, respectively, of the total dry matter intake). The daily feed intakes were determined and the sheep were weighed weekly for 10 weeks. The sheep showed a marked preference for fresh mucuna forage over either the dried or ensiled forms. The total dry matter intake increased by 15% and 21%, respectively, with M20 and M25. All the groups lost weight over the feeding period. However, only M0 gave weight losses during the second half of the feeding period. The feed conversion efficiency followed a trend similar to that for weight gains. M20 had the greatest effect on growth and feed conversion efficiency.

Three experiments were conducted to measure the preference, voluntary feed intake (VFI), and digestibility of forest type (FT) sheep fed untreated rice straw (RS) and supplemented with either sole or combined fodder tree leaves [Leucaena (L), Samanea (S) or Gliricidia (G) and their equal combinations]. The preference index (PI) was determined by consumption difference of the three fodder tree leaves (FTL), using 12 FT sheep (6 rams and 6 ewes of average weight 17.0 ± 1 kg). The sheep were offered the FTL in a cafeteria-style, and the consumption within the first 1 h was used to rank them. The sheep showed marked preference (P < 0.0001) for Leucaena over either Samanea or Gliricidia. The PI followed this order: Leucaena > Samanea > Gliricidia. For the VFI study, a total of 24 FT sheep (16 rams and 8 ewes) of average weight 17.0 ± 1.0 kg were randomly assigned to 1 of 8 dietary treatments in a completely randomized design. The treatments were T1 (100% urea-ammoniated straw), T2 (RS + 100% L), T3 (RS + 100% S), T4 (RS + 100% G), T5 (RS + 50% L:  50% S), T6 (RS + 50% L: 50% G), T7 (RS + 50% G: 50% S), T8 (RS + 33% L: 33% G: 33% S).  There were significant differences in the total and straw DM intakes. Total DM intake ranged from (523 to 694 g/d) whilst straw DM intake ranged from (430 to 692 g/d). The highest (P < 0.0001) total and straw DM intake were observed in sheep fed T8 and T1 diets compared to the other treatment diets. Feeding sole Gliricidia resulted in the lowest straw and total DM intakes but combining it with either Leucaena or Samanea improved intakes. In the digestibility study, 16 rams (average weight = 17.0 ± 1.0 kg) and same treatments for the VFI study were used to determine DM digestibility (DMD) and digestible organic matter in dry matter (DOMD). The DMD values ranged from 52.50% to 67.20 % while the DOMD was between 55.14 and 70.36%. Feeding T1 resulted in the highest (P = 0.027) DMD, and (P < 0.0001) DOMD but combining the FTL improved DMD and DOMD for the supplemented diets. The results of the study indicated that feeding combined FTL (3 FTL) resulted in a similar performance as that of the urea-ammoniated straw and could be used a low-cost protein supplement for sheep on low-quality roughage.