Evaluation of cassava foliage as a protein supplement for sheep

Abstract

Three trials were conducted to evaluate the potential of cassava (Manihot esculenta) foliage (leaves and petioles) as a protein supplement for sheep. In the first trial, nylon bag degradability of cassava foliage was studied. Proximate analysis of cassava foliage was conducted before and after the incubation. Rumen Ammonia Concentration (RAC) and pH were determined at 0, 4 and 8 hours after feeding cassava foliage diet (30%). Proximate composition of sundried cassava foliage was (%) DM 91.25, CP 18.55, NDF, 31.41, ADF, 29.2, EE, 6.6, Ash, 12.95. Nylon-bag dry matter disappearance (DMD) increased significantly (P<0.05) from 15.75% to 75.5%. RAC values increased significantly from 8.20mg NH3/100ml at zero hour to 11.41mg NH3/100ml at 8 hours post feeding. Rumen fluid pH was not significantly changed by the 30% cassava foliage diet. In the second trial lasting 56 days, twenty-eight Yankasa/WAD yearling rams of initial average weight of 18kg were balanced for weight and randomly allotted to seven treatments. All rams except those on control diet were fed cassava foliage or groundnut haulms or both at 1.0% or 1.5% of body weight (BW) as supplements to a basal diet of Gamba hay. Feeding Gamba hay alone (control) resulted in weight loss (-30.5g/day) but with cassava foliage or groundnut haulms supplementation at 1.0% BW, significantly higher gains of 39.2 and 44.6g/day were achieved respectively. At 1.5% BW level of supplementation with cassava foliage or groundnut haulms higher weight gains of 41.2 and 51.7g/day were achieved while feeding the (50.50) combined supplements at 1.0 and 1.50% BW resulted in live weight gains of 65.1 and 69.3g/day respectively. The third trial consisted of a four week grazing trial followed by a metabolic study. Twenty-one Yankasa/WAD yearling rams were randomly allotted to seven treatments and were balanced for live weight. All rams were allowed to graze standing digitaria hay as basal diet, except the rams on control diet. Those on treatment were fed cassava foliage or groundnut haulms or a (50:50) combination of both at 0.5% and 1.0% (BW). The metabolic study consisted of a seven day adjustment period and a seven day total collection period. There was no significant difference (P>0.05) in the live weight gains of rams on the control diet compared with those supplemented except for those supplemented with cassava foliage and groundnut haulms combined at 1% level where the weight gain was significantly higher (P<0.05).Feed intake was not significantly (P>0.05) affected by feeding either supplement. Supplementing digitaria hay with cassava foliage at both 0.5% and 1.0% BW did not significantly increase the nitrogen retention values, but groundnut haulms supplemented at 1.0% BW significantly (P<0.05) increased the nitrogen retention values.
Keywords: Cassava foliage, nylon-bag degradation, rumen-ammonia, concentration incubation, dry matter disappearance, nitrogen retention.