Effect of homofermentative lactic acid bacteria and exogenous hydrolytic enzymes on the ensiling characteristics and rumen degradability of alfalfa and corn silages

Homofermentative lactic acid bacteria increase lactic acid concentrations and, therefore, decrease pH of silages. Fibrolytic enzymes hydrolyze structural carbohydrates and increase fiber degradation. The goal of this research was to examine the effects of a combination of 4 homofermentative lactic acid bacteria and 4 hydrolytic, predominately fibrolytic, enzymes on the ensiling characteristics of alfalfa and corn silages in a laboratory. Alfalfa and corn were treated with water (control: CON) or the lactic acid bacteria/fibrolytic enzymes (TRT) and ensiled in tube mini silos (volume of 1,206 cm3) and bucket mini silos (volume of 21,504 cm3) for 59 d. The pH was measured on d 1, 2, 3, 7, and 13 for alfalfa and d 1, 2, 3, 7, and 17 for corn. The additive increased the rate of pH decline (P = 0.005), DM degradation (P = 0.02), and concentration of lactic acid (P = 0.01) in the TRT alfalfa silage compared with CON. Additionally, pH on d 59 (P = 0.07) tended to be decreased in the TRT alfalfa silage compared with CON. In contrast, no difference was detected in rate of pH decline (P = 0.91) or DM degradation (P = 0.71) between treatments for the corn silages. Lactic acid (P = 0.08), however, tended to be greater on d 59 in the TRT corn silage compared with the CON. These findings indicate that the additive may improve silage characteristics and fiber degradation in alfalfa, while having no detectable effect on corn silage.