ABSTRACT.
Ruminal degradability of different components of the tagasaste plant (Chamaecytisus proliferus spp. palmensis) using steer with ruminal fistula technique

Susana Arredondo S.1, Ernesto Jahn B. y Carlos Ovalle M.
 

Chemical composition and in situ degradation of five different components of tagasaste (Chamaecytisus proliferus subsp. palmensis); new leaf, mature leaf, soft stem, ripe stem less than 1 cm in diameter and ripe stem greater than 1 cm in diameter, were evaluated.
Four Holstein steers, with ruminal fistulae were used. Food samples were incubated in the animals for: 3, 6, 10, 16, 24, 48 and 72 hours.
The animals received between 2 and 3,8 kg DM tagasaste steer day, for a period of 21 days, before and during the evaluation, in order to get used to the tagasaste.
Leaves had the highest CP content (20.0%) and the lowest ADF (19.8%). Lig, A and ME in leaf contents were 7.3, 5.4 and 2.6% respectively. The nutritive value for stems decreased according to the maturity stage; the CP content decreased from 12.5 to 4.0%, while ADF content increased from 42.1 to 59.7% for soft stem.
The potential maximum values (%) of ruminal degradability, ofthe different variables analized, were obtained for leaves, the degradability at 72 hours were 86.1 %,86.7%,64.1% and 91.3%, for DM, CP, ADF. and ME respectively. The ruminal degradability decreased for the soft stem. the maximum values of degradability at 72 hours incubation, were 60.8, 61.7,50.5 and 70.2% for DM. CP, ADF and ME. respectively. The ripe stem, on the other hand, were the components of tagasaste plant that present the lowest values of ruminal degradability for the different variables analyzed.
In accordance with the results obtained, the new and mature leaves of tagasaste, have a high nutritive value, soft stems have a lower quality, and the ripe stems less and greater than 1 cm of diameter have a limited nutritive value.

Keywords: Tagasaste. ruminal degradability, nutritive value. chemical composition, fodder shrub.
1 Centro Regional de Investigación Quilamapu (INIA), Casilla 426, Chillán, Chile.