Fiber composition, in vitro true digestibility, and fiber degradation of hempseed meal compared to mainstream feedstuffs using equine feces as microbial inoculum within the DaisyII Incubator

Recent changes in legislation have put hempseed meal (Cannabis sativa L.; HSM) under consideration as a potential livestock feedstuff. Digestibility of HSM has been researched in other species, however, there are little data in horses. The study objective was to determine the in vitro true digestibility (IVTD) of HSM compared to common equine feedstuffs. An in vitro split-split plot design used four geldings (8.5 ± 3.9yr; 558.4 ± 31.0kg; 6.0 ± 0.4 BCS) to investigate the IVTD of HSM compared to alfalfa hay (ALF), Coastal Bermudagrass hay (CBH), soybean meal (SBM), rice bran pellets (RBP), and a commercial concentrate (Bluebonnet Equilene Pellets; EQU). Fresh feces were collected after a 21-d acclimation period and used as incubation inoculum. Dried ground feed samples were incubated in ANKOM filter bags within 2 DaisyII incubators for 48h. Split samples were analyzed for pre-fermentation neutral detergent fiber (NDF). Incubated filter bags were dried and analyzed for NDF to determine IVTD and fiber degradation. Hempseed meal NDF was greater than ALF (P < 0.001), RBP (P < 0.001), and SBM (P < 0.001) but less than CBH (P < 0.001) and tended to be greater than EQU (P = 0.077). The IVTD of HSM was greater than CBH (P < 0.001) but less than all other feedstuffs (P < 0.001). The results indicate that HSM has an NDF and IVTD between ALF and CBH. Due to its lower digestibility and NDF content compared to concentrates, HSM has potential to be used as a fiber source in equine rations.