With the goal of evaluating the effect of multinutrient blocks (MNB) on the use of poor roughages (sorghum straw (PS) and Pennisetum pedicellatum Trin. Hay (Pp)), « in sacco » degradation study was conducted with rams fitted with rumen cannulaes. Four experimental treatments: T1, PS + block without phosphorus (BMN0); T2, PS + block with phosphorus (BMNP); T3, Pp + BMN0; T4, Pp + BMNP, were compared to two control treatments: one, (T5) corresponding to animals using an intensive fattening feed (40 % PS + 60 % concentrated « KIBSA ») and the other corresponding to the situation of animals using natural pasture in April (T6), May (T7), and early June (T8). The degradation of dry matter (MS) showed significant variations (P<0.1 %) with the treatments: 57.91 %; 58.8 %; 62.8 %; 60.8 %; 59.0 %; 57.3 %; 45.5 % and 53.0 % for Pp after 96 hours incubation, respectively for T1, T2, T3, T4, T5, T6, T7, and T8. The disappearance of ADF and NDF followed the same pattern; the highest values were recorded with experimental treatments and T6. These variations may be due to the joint effect of the continuous supply of N-NH 3 and the level of acidity in the rumen. It is concluded that MNB, because of their continuous supply of N-NH 3 and other nutrients, allow significant improvement of poor roughages degradability in the rumen. This offers possibilities for their valorization for meat production and for the maintenance of pregnant or lactating female during hot dry season.

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