Effects of an exogenous protease on the fermentation and nutritive value of corn silage harvested at different dry matter contents and ensiled for various lengths of time

Abstract

The objective of this experiment was to evaluate the effects of adding an experimental protease to corn plants harvested at different maturities on silage fermentation and in vitro ruminal starch digestibility (IVSD). Corn plants were harvested at maturities resulting in plants with 31 or 40% dry matter (DM). Plants were chopped, kernel processed, and treated with (1) only a 0.1 M phosphate buffer (pH 5.5, 5% vol/wt of fresh forage), (2) buffer with protease to obtain a final concentration of 20mg of protease/kg of wet forage, and (3) buffer with protease to obtain a final concentration of 2,000 mg of protease/kg of wet forage. Treated forages (about 500 g) were ensiled in nylon-polyethylene pouches and stored between 21 and 23°C for 0, 45, 90, and 150 d. Data were analyzed as a 2 × 3 × 4 factorial arrangement of treatments, with the main effects of harvest DM, dose of protease, days of ensiling, and their interactions. The treatment with the highest dose of protease resulted in more robust fermentations across harvest DM with higher concentrations of lactic and acetic acids compared with untreated silage. Concentrations of soluble protein (% of crude protein) increased with time of ensiling, regardless of DM content at harvest. However, averaged over both harvest DM contents, it increased by 37% for silages treated with the high dose of protease compared with an average 11% increase for untreated silages and silage treated with the low dose of protease, between d 0 and 45. Averaged over both harvest DM contents, the concentration of soluble protein peaked in silages treated with the high dose of protease after 45 d of ensiling, whereas it peaked at d 90 in untreated silages and silage treated with the low dose of protease. Similar changes occurred in the concentration of NH3-N due to length of ensiling and treatment with protease. In fresh forages, the concentration of starch for early- and late-harvested forages was similar, but IVSD was lower in the latter. After 45 d of ensiling, IVSD was highest in both early- and late-harvested silages that were treated with the high level of protease. After 150 d of ensiling, IVSD was similar among silages treated with protease, regardless of DM at harvest. Treating corn plants with a high dose of an experimental protease at harvest accelerated proteolysis during ensiling, resulting in corn silages with levels of IVSD after 45 d of ensiling that were only obtained in untreated corn silages after 150 d of ensiling.

Effects of length of ensiling and maturity group on chemical composition and in vitro ruminal degradability of whole‐crop maize

“…However, for silages higher in DM, the increase in starch degradability can be lasting longer. This was, for example, shown by Windle, Walker, and Kung () where a significant increase in the ruminal in vitro starch degradability of whole‐crop maize (DM 400 g/kg) still occurred between 90 and 150 days of storage. Also Der Bedrosian, Nestor, and Kung (), for two hybrids with higher DM (410 g/kg), observed an increase in starch degradability with progressing length of storage, whereas it remained constant for the hybrid ensiled at DM 320 g/kg.…”

Effects of different source additives and wilt conditions on the pH value, aerobic stability, and carbohydrate and protein fractions of alfalfa silage

“…After treatment, the samples were placed in vacuum‐sealed polyethylene plastic bags (240 mm × 480 mm; embossed food saver bag; TaizouWenbwu Soft‐Packing Color‐Printing Co. Ltd., Zhejiang, China) for 45 days, in triplicate, as reported by Windle et al . (). An attempt was made to conserve approximately 500 g of the forage sample for each treatment, and three bags were packed as laboratory replicates.…”

“…The amount of LAB, mold, yeast and aerobic bacteria was measured using the method recommended by Windle et al . (). The colonies were counted as viable numbers of microorganisms (log colony forming units (cfu)/g of FW or log cfu/mL of solution).…”

Effects of an inoculant containing a Lactobacillus buchneri that produces ferulate-esterase on fermentation products, aerobic stability, and fibre digestibility of maize silage harvested at different stages of maturity

“…In agricultural practice, however, forage maize is often harvested earlier or later than the optimum time for harvesting (Herrmann et al, 2005;Windle et al, 2014). More common reasons for harvest to occur outside of the recommended range of maturity are unfavourable weather conditions, inadequate capacity to harvest large amounts of forage in a short period of time, unavailability of custom harvest equipment at the optimal harvest time, errors when choosing the maturity class of hybrids, or lack of monitoring whole plant moisture or kernel milk line during the filling period (Windle et al, 2014). Harvesting too early can be unfavourable, because the energy content of maize silage is lower due to incomplete starch accumulation in the kernels (Wiersma et al, 1993).…”