DIGESTIBILIDAD IN SITU DE LA MATERIA SECA DE TRES DIETAS PARA OVINOS DE ENGORDA.

The objective of this work was the measure the in situ and ruminal degradability and dry matter digestibility of three fattening diets for lambs, used by lamb producers in the central area of Tamaulipas, México. The nylon bag technique was used to determine in situ dry matter digestibility, using three lambs with cannulas in the rumen, distributed in a Latin Square design. The ruminal incubation times were 0, 4, 8, 12, 24 and 48 h. All treatment diets (T) used ground sorghum grain (Sorghum vulgare) as a base. T1 included rice (Oryza sativa) polishing with 7.53% on a dry matter basis (DM) of sorghum straw as forage; T2 had 5% DM of sorghum straw as forage; and T3 had 5% DM of buffel grass (Cenchrus ciliaris) hay plus 3% DM of alfalfa hay (Medicago sativa). In T1, the highest (P<0.05) value of digestibility at 0 and 4 h was observed. For 24 h, the highest (P<0.50) digestible fraction was obtained with T2. At 48 h, no difference (P>0.05) was observed between treatments. The washing loss and the degradation constant were higher (P<0.05) for T1 than T2 and T3. The diet of T1, containing rice polishing, produced the highest digestible fraction at the fi rst hours of incubation in rumen (0 and 4 h). T3 was digested in smaller proportion, although it could be the best diet for feedlots of lambs because of the lower acidosis risk. [ABSTRACT FROM AUTHOR]