Intake, digestibility, and nitrogen balance of sheep fed bambara groundnut haulm as supplement to a maize stover basal diet

The study was conducted to evaluate the agronomic and nutritional characteristics of Bambara groundnut haulms fed to rams as supplement to a maize stover basal diet. Four cultivars of Bambara groundnut were selected from forty Bambara cultivars obtained from the International Institute of Tropical Agriculture (IITA) based on their agronomic and nutritional characteristics for metabolism studies using four Djanllonke rams with an average weight of 15.0 ±0.5 kg. Four selected cultivars of Bambara groundnut haulm, TVSU (138), TVSU (879), TVSU (690), and TVSU (1446) were evaluated using the in vitro gas production technique. The animals were assigned randomly in a 4x4 Latin square design to one of the four test diets namely, T1 (Maize stover only, the basal diet), T2 (Maize stover + 150 g Bambara groundnut haulm), T3 (Maize stover + 300 g Bambara groundnut haulm) and T4 (Maize stover + 450 g Bambara groundnut haulm). The grain yield estimates of all the cultivars ranged from 0.21-4.9t/ha with cultivars TVSU1446 (0.54 t/ha), TVSU138 (0.73 t/ha), TVSU690 (2.3 t/ha) with TVSU879 recording the highest yield of (3.3 t/ha). The haulms yield also ranged from 2-24 haulms per stand at harvest. Whereas TVSU879 recorded the highest (15 haulms per stand), both TVSU690 and TVSU1446 recorded 9 haulms per stand and TVSU138 had the lowest haulms yield of 3 per stand. The chemical analysis indicated a dry matter range of 90.24 (TVSU138) to 90.80% (TVSU1446), crude protein ranged from 14.32 (TVSU690) to 16.15% (TVSU138), neutral detergent fibre range 47.34% (TVSU1446) to 68.45% (TVSU879). While that of acid detergent fibre ranged from 33.46% (TVSU690) to 43.65% (TVSU138). Percentage ash contents recorded were 8 for TVSU690, 9 for TVSU1446, 9.5 for (TVSU879) and 11 for (TVSU138). Dry matter intake of the basal diets increased as the supplement level increased (P<0.05). Cumulative gas production at 48 and 72hr was highest for TVSU (879). The highest fermentative gas production was recorded by vii TVSU690 (34.61) followed by, TVSU1446 (30.90), TVSU879 (23.84) and TVSU138 (21.47). There were significant differences (P<0.0001) among the four cultivars in terms of the gas production parameters. The rates of gas production ranged from 0.04 to 0.07 h -1 . Cultivar TVSU879 (0.07 h -1 ) was significantly (P<0.0001) highest compared with the other cultivars which recorded the same rate of gas production of 0.04 h -1 . The total feed intake did not show any significant (P>0.05) difference at all levels of supplementation. Digestibility co-efficient was significantly lower (P<0.05) for T1 which had no Bambara groundnut haulm supplementation compared to the other treatment groups supplemented with BGH which were also statistically (P>0.05) similar. Generally, faecal, urine and nitrogen balance values amongst the treatment groups did not differ (P>0.05) significantly. From the current study, it can be concluded that, Bambara groundnut haulm seems to be underutilized though could be used to supplement poor quality roughages to increase productivity of ruminant livestock in tropical regions and possibly replace the conventional feed supplements. Furthermore, the four cultivars of the Bambara groundnut haulm under study revealed that they could be valuable alternative animal feed sources in ruminant feeding.

Source: KNUST