PSX-11 - Effect of preservation method on nutritive value of kudzu forage

Abstract: “The vine that ate the South,” also known as kudzu (Pueraria montana [Lour.] Merr.) is a
drought-tolerant perennial leguminous vine that was introduced from Asia to the United States as
an ornamental crop. It was quickly recognized and favored as a solution to soil erosion during
the Dust Bowl. However, due to its ability to quickly overtake existing vegetation, it was
ultimately labeled as an invasive species by the USDA. Given current sustainability efforts,
interest has renewed in ways to incorporate this invasive species for productive agricultural
purposes. The goal of this study was to investigate how preservation (i.e., haying) would affect
the nutritive value and digestibility of kudzu forage. Kudzu was harvested from a private
property in Auburn, Alabama. Two independent plots on the property were utilized; half of the
fresh biomass was immediately removed, and the remaining half was removed at 20% moisture
for the sun-cured sample. Samples were collected from each plot and assayed for NDF, ADF,
ADL, and CP. Samples were also assayed for in vitro true and NDF disappearance (IVTD and
IVNDFD, respectively) as well as in situ ruminal disappearance. Data were analyzed using SAS
v. 9.4. There was no effect of preservation on NDF, ADF, ADL, and CP concentrations (P ≥
0.39). However, kudzu samples subjected to sun-curing had greater IVTD (64.3%, P < 0.01)
and IVTD_OM (63.0%; P < 0.01) and tended to have greater IVNDFD (35.6%; P = 0.06) than
fresh kudzu (59.4, 57.8, and 31.3%, respectively). There was no effect (P ≥ 0.12) of preservation
on the potentially degradable fraction, lag time, or rate of digestion of kudzu samples. However,
fresh samples had a greater (P < 0.01) undegradable residue than did sun-cured samples (49.3 vs.
38.8%). The improvements in digestibility are interpreted to mean that preservation methods,
such as sun-curing, may be valuable for increasing the value of kudzu as a roughage source for
ruminant livestock production systems.