Biogas, degradation, metabolizable energy, alternative feed.
Objective: To determine the in vitro biogas production and fermentative characteristics of diets for fattening lambs containing 20% chipile or crotalaria at 30 or 40 d of regrowth.
Methodology: The treatments were whole diets containing 20% crotalaria with 30 d (T1) or 40 d of regrowth (T2), as well as 20% chipile with 30 d (T3) or 40 d of regrowth (T4). In vitro gas production was measured at 2, 4, 6, 8, 10, 12, 24, 48, and 72 h and the following elements were determined: kinetic estimators (A, b, k), dry matter (DMD), organic matter (OMD), neutral detergent fiber (NDFD), and acid detergent fiber (ADFD) degradation, metabolizable energy (ME), and short-chain fatty acids (SCFA). The experimental design was completely randomized.
Results: Regarding the accumulated biogas production, T4 presented higher production from 2 to 24 h, T3 and T4 higher at 48 h, and T1 higher at 72 h. Kinetic estimators showed that T1 was higher in A and k and T4 was higher in b. T2 presented the lowest DMD, OMD, NDFD, ADFD, ME, and SCFA.
Study Limitations: Scale production of chipile, aimed to obtain a greater biomass volume, is limited since it has not been domesticated yet.
Conclusions: Sheep diets containing 20% chipile or crotalaria with 30 d of regrowth have proven to be an alternative for the manufacturing of whole diets for the intensive fattening of lambs in the tropics.