Effect of delayed wrapping on preservation and quality of whole crop barley forage ensiled as large bales

Abstract

The effects of delayed bale wrapping on fermentation characteristics, preservation and quality of whole barley crop ensiled as large bales (LBS) were examined. Forage was cut at the early milk stage and allowed to wilt over 24-h period to 47% DM. Bales were allocated to one of three treatments requiring that bales be wrapped within 2, 10 and 19 h post-baling. Bales were sampled at baling and on days 1, 2, 3, 6, 9, 13, 17, 29, 64, 92, 252 and 308 post-baling. Bales were weighed prior to being wrapped and when removed from storage to measure DM and nutrient losses during storage. During wrapping, a thermocouple wire was inserted in each bale to monitor bale temperature. Bales wrapped within 2 and 10 h were similar (P > 0.05) for storage temperature, nutrient profile and recovery, and for lactic and volatile fatty acid content. Lactic acid concentrations peaked between 29 and 64 d post-ensiling for bales wrapped 2 and 10 h post-bailing, but did not peak until day 92 for bales wrapped at 19 h post-bailing. Storage temperature of bales wrapped after 2 and 10 h post-bailing did not exceed 30 °C during storage, but bales wrapped 19 h later exceeded 30 °C for the first 19 d during storage. Bales wrapped within 19 h had a lower (P < 0.05) water soluble carbohydrate content and a higher acid detergent insoluble N and ammonia N level compared to 2 and 10 h bales. The pH and 2, 3 butanediol levels were higher (P < 0.01) in 19 h compared to 2 and 10 h bale silage. A 64 d ensiling period was required to achieve minimum pH values in LBS wrapped with 10 h post-baling, the length of time being greater when wrapping was delayed to 19 h post-baling. Results from this study indicate that delaying bale wrapping to the next day resulted in a temperature rise, and poor silage protein quality. Wrapping 2 h post-baling was not an advantage to wrapping 10 h post-baling in whole crop barley ensiled as large bales. Key words: Silage, large bale, whole crop barley, delayed wrapping, ensiling characteristics