233 Fermentation Characteristics of Brassica and Wheat Mixed Silages

Abstract

Abstract Winter feed management in the temperate regions of the U.S. primarily consists of stored or stockpiled grasses. Recently, forage brassica species have become popular additions to fall and winter grazing programs as an alternative feed source. Most all brassicas incorporated into forage systems are grazed; however, there may be more feeding options, such as fermenting them as silage or baleage. The objective of this project was to determine, utilizing a laboratory scale process, the feasibility and quality characteristics of two different brassica species alone or mixed with winter wheat. Forages were planted in 25.4 cm pots at a seeding rate comparable with field application. Three separate forage varieties were used: a hybrid forage rapeseed (RAPE), a forage turnip (TURNIP) and winter wheat (WHEAT). Along with these 3 varieties, two mixed forage treatments were utilized; a 3-way mix spaced and covered mimicking the effect of being planted with a drill (DRILL) and a 3-way mix randomly sprinkled and left uncovered mimicking a more random application (BROADCAST). Each of these 5 treatments were replicated 5 times and grown in the greenhouse for 76 d. At the conclusion of this growing period, forages were harvested 3 cm above the soil and immediately placed into vacuum-sealed bags. Bags were placed in a dark room and incubated for a total of 83 d. Following incubation, samples were analyzed for fermentation characteristics to determine quality of the ensiling process. Data were analyzed using the MIXED procedures of SAS. There was a treatment effect (P < 0.01) on the DM of the ensiled product whereby WHEAT (31.8%) was the greatest and BROADCAST (7.1%) was the least. The BROADCAST treatment had significantly (P < 0.01) greater ammonia concentration, as well as acetic acid (P < 0.05) concentration compared with all other treatments. No differences (P = 0.26) in pH were observed within the ensiled treatments. Overall, results of this trial suggest that it might be possible to use these brassica species as an ensiled feedstuff, though further testing is necessary to elucidate possible complications or limitations.