Effects of a propionic acid-based additive on short-term ensiling characteristics of whole plant maize and on dairy cow performance

Dairy cattle producers occasionally face situations where it is necessary to open silos before the completion of ensiling process due to feed shortage. The objectives of this study were to determine the effects of a propionic acid additive (i.e., Solution Foin; 700 ml/L propionic acid and 300 ml/L NH4OH) on ensiling characteristics, aerobic stability and feeding value of short-term ensiled forage maize. Chopped whole maize was left untreated or treated with the additive. The additive was added prior ensiling at a rate of 5 L/ton (wet basis). Treated and untreated forages were placed in plastic silo bags, which were opened 1 day after ensiling and sampled daily for 30 consecutive days. Animal performance was determined using lactating cows fed total mixed ration with the major forage portion consisted of untreated or treated maize. The feeding study started 2 day post-ensiling. The additive reduced (P<0.05) yeast and mold populations between day 5 and day 14 post-ensiling. The largest differences were observed on day 10, where yeast and mold populations for untreated ensiled maize were 7.86 and 2.51 log colony forming unit/g, respectively, the corresponding values for treated maize were 4.35 and 0 log colony forming unit/g, respectively. The additive improved (P<0.05) aerobic stability between day 0 (by 159 h) and day 10 (by 33 h) post-ensiling. No differences in pH or concentrations of organic acids were observed between treated and untreated maize. Dry matter intake (average 23 kg/d) and milk yield (average 29 kg/d) were similar for cows fed treated and untreated maize. Solution Foin can be used to improve the aerobic stability of partially ensiled maize, likely by reducing yeast and mold populations. However, the additive had no positive effects on silage fermentation or dairy cow performance.