Sainfoin (Onobrychis viciifolia) is a tanniniferous legume forage that has potential nutritional and health benefits preventing bloating, reducing nematode larval establishment, improving N utilization, and reducing greenhouse gas emissions. However, the use of sainfoin as a fodder crop in dairy cow rations in northwestern Europe is still relatively unknown. The objective of this study was to evaluate the effect of sainfoin silage on nutrient digestibility, animal performance, energy and N utilization, and CH4 production. Six rumen-cannulated, lactating dairy cows with a metabolic body weight (BW(0.75)) of 132.5±3.6kg were randomly assigned to either a control (CON) or a sainfoin (SAIN)-based diet over 2 experimental periods of 25 d each in a crossover design. The CON diet was a mixture of grass silage, corn silage, concentrate, and linseed. In the SAIN diet, 50% of grass silage dry matter (DM) of the CON diet was exchanged for sainfoin silage. The cows were adapted to 95% of ad libitum feed intake for a 21-d period before being housed in climate-controlled respiration chambers for 4 d, during which time feed intake, apparent total-tract digestibility, N and energy balance, and CH4 production was determined. Data were analyzed using a mixed model procedure. Total daily DM, organic matter, and neutral detergent fiber intake did not differ between the 2 diets. The apparent digestibility of DM, organic matter, neutral detergent fiber, and acid detergent fiber were, respectively, 5.7, 4.0, 15.7, and 14.8% lower for the SAIN diet. Methane production per kilogram of DM intake was lowest for the SAIN diet, CH4 production as a percentage of gross energy intake tended to be lower, and milk yield was greater for the SAIN diet. Nitrogen intake, N retention, and energy retained in body protein were greater for the SAIN than for the CON diet. Nitrogen retention as a percentage of N intake tended to be greater for the SAIN diet. These results suggest that inclusion of sainfoin silage in dairy cow rations reduces CH4 per kilogram of DM intake and nutrient digestibility. Moreover, sainfoin silage improves milk production and seems to redirect metabolism toward body protein accretion at the expense of body fat.

The current study has two objectives: (1) To determine the effect of different lactic acid bacteria (LAB) strains’ inoculant on silage quality of fresh ryegrass (FR) and rain-treated ryegrass (RTR), and (2) to find the optimal way (silage inoculant vs. direct-fed microbial (DFM)) to use LAB strains in order to improve nutrient digestibility and reduce methane emission (CH₄) in ruminant production. Five LAB strains were tested, Lactiplantibacillus plantarum AGR-1, L. plantarum AGR-2, Lactococcus lactis subsp. lactis biovar diacetylactis AGR-3, L. lactis subsp. lactis AGR-4 and L. lactis subsp. lactis AGR-5. Each LAB strain was inoculated at 10⁶ cfu/g fresh weight into the FR and the RTR and ensiled for 60 days. After ensiling, the effect of LAB strains included as a DFM or silage inoculant on rumen digestibility and CH₄ production were measured using an in vitro gas production system with three separate runs. The in vitro experiment consisted of 24 treatments (2 grasses (FR and RTR) × 2 ways (inoculant or DFM) × 6 strains (5 LAB strains + 1 Control)). The results indicated that the LAB strains’ inoculant treatments reduced (p < 0.0001) the dry matter (DM) losses, the NH₃ concentration (p < 0.0001) and the pH (p = 0.0019) upon ensiling in both the FR and the RTR. The lowest values in dry matter (DM) loss and NH₃ concentration were found in the L. plantarum (AGR-2) and L. lactis (AGR-5). The in vitro CH₄ production was lower for silages inoculated with L. plantarum (AGR-1, p = 0.0054), L. lactis (AGR-4, p = 0.026), L. lactis (AGR-5, p = 0.029) and L. plantarum (AGR-2, p = 0.090), compared to the control. Methane production was lower (p = 0.0027) for LABs when used as silage inoculants, compared to being used as DFM. Lactic acid bacteria used as silage inoculants increased (p ≤ 0.0001) the in vitro DM and organic matter (OM) degradability both in the FR and the RTR, whereas LAB strains used as DFM showed no such effect. The DM and OM digestibility were highest in the L. plantarum (AGR-1, p = 0.0175). Among the five LAB strains used in the current study, L. plantarum (AGR-2) was the best candidate to improve silage quality. Our observations suggest that these LAB strains are most promising when used as silage inoculants and to be confirmed in vivo.