The purpose of this study was to determine the ruminal degradability of dry matter, crude protein, neutral detergent fiber and their fractions, contained in regrowth of mulberry at 56, 84 and 112 days. The degradation of leaves, stems and the whole plant was calculated. The potential degradability of these three components diminished as the regrowth aged. The soluble fraction of the dry matter was reduced from 29% to 25% in the leaves and from 27% to 19% in the stems between the 56th and the112th day. The degradable fraction in the stem remained constant (61-63%) on the three measuring days, with ruminal degradation levels of 14%, 10% and 9%/h respectively. In the stem the degradable fraction diminished from 42% to 30% between the 56th and 112th day, with degradation speeds of 8.4%, 6.7 % and 5.3%/h. The soluble crude protein diminished with age from 41% to 33% in the entire plant and the degradable fraction remained constant between 49% and 51%. The degradation rate was higher than 9.4%/h. The neutral detergent fiber had a degradable fraction of 71%, 62% y 43% on the 56th, 84th and 112th day, with degradation rates of 13%, 10% y 9%/h respectively. The degradation of the neutral detergent fiber began in the rumen with a lag time of 1.5 to 3.2 hours.