Vinasse added to dried sugar beet pulp: Preference rate, voluntary intake, and digestive utilization in sheep1

Abstract

Three experiments were performed to study the nutritional characteristics of sugar beet pulp (SBP) according to the concentration of vinasse (condensed molasses solubles) added. Eighteen Merino ewes were used to study preference in Exp. 1, and 18 Merino ewes were used in Exp. 2 to study voluntary intake of SBP with different amounts of vinasse inclusion (0, 7, and 13% on a DM basis; SBP0, SBP7, and SPB13, respectively). Sheep showed a marked preference for SBP with vinasse, regardless of the amount of addition, whereas voluntary feed intake was not affected (P > 0.34). Eight ruminally cannulated Merino ewes were used in Exp. 3 to study rumen fermentation of SBP0 and SBP13. Regardless of the diet fed to the animals (SBP0 or SBP13), disappearance rates of DM, NDF, and CP were greater when SBP13, compared with SBP0, was incubated in sacco (P < 0.05), and NDF and CP disappearance rates were increased when animals were fed the SBP13 diet. No significant differences were observed for pH, ammonia concentration, or total or individual VFA in the ruminal liquor of sheep at different sampling times after feeding (P > 0.23) in response to vinasse addition. Experiment 4 was designed to study digestibility, solid passage rate, and excretion of purine derivatives from 12 Merino ewes fed SBP0 and SBP13. Digestibility of NDF tended to be greater (P < 0.10) for the SBP13 group compared with the SBP0 group; digestibilities of DM, OM, CP, and ADF were not affected (P > 0.11). Digesta flow kinetics and urinary excretion of purine derivatives were not significantly affected by the presence (SBP13) or absence (SBP0) of vinasse in the diet (P > 0.21). In conclusion, sheep showed a clear preference for SBP with vinasse. However, the lack of significant differences in most of the in vivo variables measured indicates that ewes can be satisfactorily fed with any of the amounts of vinasse inclusion studied.