Comparative Analysis of Drying Techniques on the Chemical Composition and Feeding Value of Alfalfa

This study compared the effects of various drying techniques on the chemical composition and feeding value of alfalfa. The study consisted of two experiments. In Experiment 1, samples were dried at 40 °C for 60 hours, 55 °C for 48 hours, 70 °C for 36 hours, and 85 °C for 24 hours without pre-drying. In Experiment 2, samples were subjected to either pre-drying (70 °C/80 min, 100 °C/60 min, or 130 °C/40 min) or freezing (-20 °C for 2 months) before being dried at 55 °C for 48 h, while the control group was directly dried at 55 °C for 48 h. In Experiment 1, samples dried at 70 °C resulted in higher concentrations of crude protein and non-structural carbohydrates, as well as greater in vitro digestibility and relative feed value. In Experiment 2, the control group yielded higher crude protein concentration, in vitro true dry matter digestibility, and neutral detergent fiber digestibility. Furthermore, the samples dried at 70 °C showed the highest non-structural carbohydrates and nitrogen-free extract, as well as the highest relative feed value among groups. As a result, drying at 70 °C without pre-drying can be an effective alternative way for preserving nutritional value compared to conventional drying methods. Conversely, pre-drying treatments at high temperatures (70–130 °C) or freezing samples at -20 °C before drying did not improve the nutritional value of alfalfa.