Abstract
The dry matte(DM) degradation and its seasonal changes in eleven mulberry varieties ware determined using the nylon bag technique. The leaves were harvested on 6 July, 25 August and 23 October. Degradability was measured by incubating samples in the rumen of two fistulated Holstein cows for 4, 8, 12, 24, 48 and 96h. The degradability of the readily soluble fraction(a)rabged between 6.9-34.4% in July, 27.2-49.6% in August, and 33.6-44.5% in October. The corresponding values for the slowly degradablw fraction(b)were 61.5-87.0, 44.7-67.6 and 53.5-63.2%, respectively. The potential degradability(PD=a+b)and rate of degradation of b per h(c)ranged between 91.1-97.2% and 8-16%/h, respectively and were not significantly affected by time of harvesting and varieties. Both factors significantly affected effective degradability, which was 79.2, 81.9 and 84.8% in July, August and October, respectively, and varied between 75.0-89.5% among the varieties. The results of this study suggested the existence of varietal differences in degradability among the mulberry varieties. However, the leaves of all the mulberry varieties tested were highly degradable and therefore can serve as suitable supplements to low quality basal grass diets.
