Effects of whey powder on fermentation quality, nutritive value, and digestibility of alfalfa silage

The aim of the study was to investigate the effects of whey powder (WP) on the fermentation quality, nutritive value, and digestibility of ensiled alfalfa (Medicago sativa L.). Alfalfa treated with different doses of WP (0, 2, and 4% fresh matter silage) was ensiled in plastic drums for 60 days. The results of the study revealed that the physicochemical composition and fermentation quality of the alfalfa silage improved and that mold growth was inhibited in the groups treated with 2 and 4% WP in comparison to that in the control. Production of CO2 (day 7) was much lower in silages treated with 2 and 4% WP (3.77 and 1.85 g/kg dry matter (DM), respectively) than in the control group (21.36 g/kg DM). In addition, in vivo dry matter digestibility (DMD) was much higher in the group treated with 4% WP (76.45%) than in the control one (55.82%). In this treatment group, all apparent digestibility of coefficients in vivo from crude nutrient contents and cell wall fractions significantly increased and hence raised the net lactation energy value from 1.18 to 1.31 Mcal/kg DM. However, although the in vitro DMD was higher in the silages treated with WP than in the control one and the dose was significant, there was no strong correlation between in vivo and in vitro values. According to our results, WP could provide an advantage for the conservation of alfalfa silage. In addition, WP could be evaluated as a sustainable silage additive.