Effect of sprouted barley and alfalfa hay supplementation on rumen function and milk composition of Simmental cows

Maintaining stable rumen function in mid-lactation dairy cows is essential for supporting metabolic efficiency and milk production. Sprouted barley (SB), due to its high digestibility and improved nutrient availability, has been proposed as a partial forage replacement in dairy diets; however, evidence regarding its effects in comparison with traditional forages such as alfalfa hay (ALF) remains limited. This study evaluated the impact of substituting 15% of dietary dry matter with SB on rumen fermentation characteristics, milk composition, and productive responses of mid- lactation Simmental cows. Thirty cows were assigned to either an ALF-based control diet or a diet containing SB for 90 days. Rumen fluid samples were collected on days 10, 45, and 90 to determine pH, total volatile fatty acids (VFA), and molar proportions of individual VFAs. Milk yield and composition, dry matter intake (DMI), and body condition score (BCS) were also monitored. SB inclusion did not affect DMI, BCS, milk yield, or milk composition, indicating that partial replacement of alfalfa hay did not limit intake or compromise metabolic status. Rumen pH was influenced by diet and time, with the ALF diet supporting greater pH stability, whereas the SB diet showed a gradual decline toward day 90. Total VFA concentration decreased over time in both groups without treatment effects, and changes in acetate, propionate, and butyrate were modest and within physiological ranges. Overall, supplementing sprouted barley produced minor shifts in rumen fermentation while maintaining normal physiological function and milk quality. These results suggest that sprouted barley is a safe and practical partial forage substitute in the diets of mid-lactation Simmental cows.