Effects of a propionic acid-based additive on short-term ensiling characteristics of corn and on dairy cows performance

Forage shortage may force producers to feed unfermented or partially fermented forages, which are more susceptible to aerobic deterioration. Propionic acid-based additives can be added to ensiled forages to inhibit yeast and mold growth, and improve the aerobic stability of silages. The objectives of this study were to determine the effects of a propionic acid-based silage additive (Solution Foin) on ensiling characteristics, aerobic stability and feeding value of short-term ensiled corn forage. Chopped whole corn was left untreated or treated with Solution Foin (contains 700 g kg-1 propionic acid and 300 g kg-1 NH4OH). The additive was added to forage prior ensiling at a rate of 5 L ton-1 (wet basis). Treated and untreated forages were placed in six plastic silo bags (three each). Silo bags were opened one day after ensiling and daily samples were collected for 30 consecutive days. Effects on animal performance of feeding treated or untreated forage were determined in a completely randomized design, using 30 lactating cows (178+/-55 days in milk) fed total mixed ration (50:50 forage: concentrate) with the major forage portion consisting of untreated or treated forage. The feeding study started one day post-ensiling. Results showed that Solution Foin reduced (P < 0.05) yeast and mold populations between d 5 and 14 post-ensiling. The highest differences (P < 0.002) were observed on d 10, at which point yeast and mold populations for untreated silage were 7.86 and 2.51 log cfu g-1, respectively. The corresponding values for treated silage were 4.35 and 0.00 log cfu g-1, respectively. Aerobic stability of treated ensiled forage was also improved (P < 0.01) from day 0 (by 159 h) to day 10 (by 33 h) post-ensiling. Solution Foin also increased (P < 0.05) the overall lactic acid and WSC content, and lowered the temperature of the treated ensiled forage in the field. No treatment differences were detected in the forage pH and acetic acid concentration. Dairy cows fed treated forage had similar feed intake (average 23 kg d-1) and milk yield (average 29 kg d-1) to cows fed the untreated forage. It was concluded that Solution Foin can be used to improve the aerobic stability and ensiled forage characteristics of short-term corn forage, likely by reducing yeast and mold populations