Research progress on the preparation of alfalfa hay and silage and their applications in the ruminant diet

Alfalfa hay and silage are high-quality forages that can be stored for a long time. However, the difference in nitrogen composition and lactic acid bacteria fermentation products between them leads to differences in nutritional value. This review summarizes the research on alfalfa hay and silage in animal feeding, and finds that the effects of alfalfa hay or silage on ruminants production performance, rumen fermentation characteristics, meat or milk quality and methane emission mainly depend on three points: 1) The quality of alfalfa hay or silage. The feed intake and intestinal digestibility of alfalfa were affected by its preparation quality. 2) Combination effect with other feed materials. Rumen degradable energy nitrogen balance can improve rumen fermentation parameters. 3) Replacement feeding ratio. Low proportion of the same mass replacement feeding has little effect on the ruminants. The research progress in the preparation of some alfalfa hay (harvesting, drying and feeding) and silage (additives, bactericides and packaging) is also presented in order to provide theoretical basis for the efficient utilization of alfalfa.