Wet extrusion and chemical treatment of maralfalfa grass (Pennisetum sp)

Objectives. Test the effect of wet extrusion and the application of two alkaline compounds on the in vitro digestibility of dry matter (IVDDM) and neutral detergent fiber (IVDNDF) of maralfalfa grass. Materials and methods. 48 samples of 51 days of regrowth were chopped and assigned to eight treatments: raw, chopped, and dehydrated grass (CTRL); raw, chopped, and extruded grass (EXTR); EXTR treated with 0.45, 0.90, and 1.35% of lime (Ca(OH)2) or urea for 21 days in micro-silos under aerobic conditions (EXTR0.45Ca, EXTR0.90Ca, EXTR1.35Ca, EXTR0.45U, EXTR0.90U, and EXTR1.35U, respectively). The content of dry matter (DM), nitrogen (N), calcium (Ca), neutral detergent fiber (NDF), acid detergent lignin (ADL) and the in vitro digestibility of dry matter (IVDDM) and NDF (IVDNDF) were determined for each sample. Results. The EXTR presented lower N content, higher NDF content, and higher IVDNDF than the CTRL. On the other hand, the EXTR1.35Ca treatment showed the highest Ca concentration and the highest IVDDM and IVDNDF, while the EXTR0.90U treatment presented the highest N concentration and an IVDNDF statistically similar to that of the EXTR1.35Ca. Conclusions. The wet extrusion of maralfalfa grass alone increases IVDNDF; however, IVDDM and IVDNDF are maximized when treated with 1.35% of Ca(OH)2.