Impact of Leaf and Stem Proportions on Dry Matter and Crude Protein In Situ Disappearance of Rhizoma Peanut Genotypes

ABSTRACT Rhizoma peanut (Arachis glabrata Benth.) is a warm‐season legume adapted to the southern United States. ‘Florigraze’ is the most cultivated rhizoma peanut; however, recent studies have demonstrated that the genotype Ecoturt has attractive forage characteristics. The objectives of this study were to evaluate the effect of leaf and stem proportions on dry matter (DM) and crude protein (CP) disappearance of Ecoturf and Florigraze rhizoma peanut. Treatments were two genotypes of rhizoma peanut (Florigraze or Ecoturf) and three leaf and stem proportions (100, 50, and 0%) distributed in a randomized complete design with four replicates. Crude protein and DM disappearances were estimated using a nonlinear model. Dry matter and CP fractions were described as rapidly degradable (Fraction A), potentially degradable (Fraction B), and undegradable (Fraction C). Florigraze had greater DM Fraction A than Ecoturf (349 vs. 339 g kg−1), but there was no difference in Fractions B and C (means = 427 and 230 g kg−1, respectively). The leaf and stem proportions have significant impact on DM and CP fractions and effective degradability. There was a linear decrease in DM Fractions A and B and a decrease in Fraction C with increasing leaf proportion. Conversely, CP Fractions A and C increased with increasing leaf proportion, whereas Fraction B decreased. The leaf and stem proportions are important indicators of nutritive value of rhizoma peanut, and the models generated by this study may allow managers to have a more accurate prediction of forage nutritive value for ruminants.