The effect of homofermantative lactic acid bacteria and exogenous fibrolytic enzymes on the ensiling characteristics and rumen degradability of alfalfa, corn silages and cool season mixed grass haylage
Thesis (M.S., Animal and Veterinary Science) -- University of Idaho, 2015 | Homofermantative lactic acid bacteria (LAB) increase lactic acid concentrations, lower pH and LAB inoculants are used to improved silage. Fibrolytic enzymes (FE) hydrolyze structural carbohydrates and increase fiber degradation. The goal of this research was to examine the effects of a combination of four homofermantative LAB and four FE on the ensiling characteristics of alfalfa and corn silages in a laboratory setting (experiment I) as well as on ensiling characteristics of a cool season mixed grass haylage at farm scale (experiment II). Alfalfa and corn were treated with water, (control: CON) or the LAB/FE (TRT), and ensiled in tube mini silos (volume 1206 cm3) and bucket mini-silos (volume 21,504 cm3) for 59 d. Mixed cool season grasses were treated with water (CON), or the LAB/FE (TRT), and ensiled for 90 d in round bales. Statistical analysis for experiment I was analyzed using SAS 9.3 and experiment II was analyzed using SAS 9.4. Significance was declared at P ? 0.05. Rate of pH decline, d 1 - 13, was greater in TRT alfalfa compared to control (P = 0.005) while Lactic acid (LA), % of total organic acids, tended to be greater in the TRT alfalfa (P = 0.06) as did final pH (P = 0.07). Dry-matter degradation was greater in the TRT alfalfa (P = 0.02). Ammonia (P = 0.03) and acid detergent fiber (P = 0.02) were reduced in the TRT grass haylage. In contrast, in situ neutral detergent fiber (P = 0.05), acid detergent fiber (P = 0.04) and organic matter (P = 0.001) degradation were greater in the TRT grass haylage. These findings indicates that the LAB/FE additive used in this study may improve silage preservation while improving fiber degradation.