Sweet potato as a ruminant feed: Performance of sheep fed mixtures of the forage and root.

Résumé

Scarcity of quality forage during the dry season poses a serious problem to ruminant production in southwest Nigeria. Dried sweet potato (SP) vine and root have the potential to bridge the gap in feed supply for ruminants during this period. In a feeding trial, fifteen male West African dwarf (WAD) sheep were used to estimate the nutritive value of SP forage and root as a basat feed for ruminants during the dry season. Experimental diets consisted of SP forage and root in the following proportions, 0:100, 25:75, 50:50, 75:25, and 100:0 (forage. root). In the first part of the trial, growing WAD sheep were fed experimental diets for twenty weeks. Dry matter (DM) intake and growth rate of the animals were measured in the second part, digestibility and nitrogen balance of sheep fed the experimental diets were measured. Intake, growth rate, digestibility and nitrogen retention improved significantly (P < 0.05) when SP forage and root were mixed in the diet. The DM intake ranged from 1.8 to 4.9% body weight; growth rate, -34.1 to 86.43 g/day; DM digestibility, 64.6 to 70.4%; and nitrogen retained, 29.5 to 51.0%. Performance, digestibility and nitrogen utilization of WAD sheep was highest when SP forage and root formed equal proportions (50:50) in the diet. Mixing SP forage and root in the diet proved beneficial to growing sheep and equal proportions of the forage and root in the diet appear to be the most appropriate combination.