Preliminary evaluation of ruminal degradation kinetics of diets containing Bursera simaruba foliage flour

Background. The search for alternative forage sources has become increasingly important due to seasonal feed scarcity and the need for sustainable livestock production systems. Bursera simaruba (Sarg.) represents a promising native forage species with potential nutritional value for ruminants, but its ruminal degradation characteristics remain poorly understood. Objective. The objective of this preliminary study was to evaluate the ruminal degradation of diets with different inclusion levels of Bursera simaruba foliage flour in cattle. Methodology. Three rumen-cannulated cows (380 ± 10 kg live weight) were used to evaluate four treatments: Bs0) control diet without inclusion; Bs15) diet with 15% inclusion; Bs30) diet with 30% inclusion; and Bs45) diet with 45% inclusion. B. simaruba foliage with 90 days of regrowth was used. Ruminal degradability was evaluated using the nylon bag technique incubated at 0, 6, 12, 24, 48, 72, and 96 h. Data were fitted with the equation p = a + b (1- Exp(-ct)). Results. The rapidly soluble fraction (a) of dry matter and crude protein was higher in Bs15 (p < 0.05). The effective degradability of dry matter and crude protein at a passage rate of 0.02 h-1 was similar between Bs0 and Bs15 (p > 0.05), both being higher than Bs30 and Bs45. Implications. The 15% inclusion level of B. simaruba maintained ruminal degradation parameters similar to the control diet, suggesting potential applicability in tropical cattle feeding systems. However, this preliminary study has significant methodological limitations including confounding effects between B. simaruba inclusion and forage:concentrate ratios that limit definitive conclusions. Conclusion. The findings suggest that moderate inclusion (15%) of B. simaruba might maintain ruminal degradation parameters similar to a control diet, but additional studies with more robust experimental designs are needed to validate these results.