International Silage Conference 2-4 July 2012 - Hämeenlinna, Finland Effect of silo management factors on aerobic stability and extent of spoilage in f i il i farm maize silages Giorgio Borreani and Ernesto Tabacco Dip. di Agronomia, Selvicoltura e Gestione del Territorio University of Turin - ITALY The aerobic deterioration of silages DM losses (various authors since 1964; McDonald et al., 1991) 1964; al. 1991) reduction in animal performance (Withlock et al., 2000) al. risk for animal health due to mycotoxins and biogenic amines (Woolford, 1990; Wilkinson, 1999) 1990; Listeria and other pathogens (Fenlon and Wilson, 1991) l t idi t th Vissers et all., 2007; T b clostridia spore outgrowth (Vi l t al. t al. 2007; Tabacco et al., 2009) Bacillus and Paenibacillus spores (Te Giffel et al., 2002) al. What is the health status of the silage during consumption? Visible Spoiled with visible mould spoiled with yeast or Acetobacter spp. development increase in silage temperature Invisible g well conserved silage high feeding value Aim to identify the extent of aerobic deterioration in farm silos Invisible Visible spoiled areas moulded areas Well conserved silage Line of increased temperature due to microbial activity Yeast count and silage temperature at the silo face Yeast Yeast count Visible moulded areas Temperature Aims q y • to quantify the extent of aerobic deterioration of maize silages on commercial farms in Northern Italy • to define good management practices that should be applied as the basis for safe silage production Materials and Methods • 2005-2010) six years (2005-2010) of data collection in 107 farms g breeding Italian Friesian cows • winter and summer maize silage sampling • representative samples from silage core, peripheral areas and visible moulded spots (if present) • silage analyses for pH, lactic acid, VFA, yeast and mould Materials and Methods • feed- measure of linear feed-out rate of the working face • measure of temperatures at various depths into the working face • easu e o e e e s o o e s b e ou ded measure of the extension of the visible moulded feed- areas on the silo feed-out face Extent of mouldy spoilage in farm maize silages in Northern Italy Winter season Summer season 10% 29% 46% 29% 42% 44% More 10% 2-10% spoiled Less 2% spoiled DM losses and mould count in maize silage at farm level 100 Visible mould on silage 80 ) DM loss (%) ses 60 40 D 20 R2 = 0.8629 0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 Mould count (log CFU/g silage) Removal rates from bunkers and piles Measured in meters per week ranged from 0.32 to 2.69 m in summer from 0.24 to 3.15 m in winter feed- Silo face visibly moulded in relation with feed-out rate: WINTER CONSUMPTION Mouldy areas below 2% Silo fac visibly moulde (%) 20 ed 16 12 y 8 4 ce 0 0.0 0.4 0.8 1.0 1.2 1.6 2.0 2.4 2.8 3.2 feed- Weekly feed-out rate from the silo face (m) feed- Silo face visibly moulded in relation with feed-out rate: SUMMER CONSUMPTION Mouldy areas below 2% Silo fac visibly moulde (%) 20 ed 16 12 y 8 4 ce 0 0.0 0.4 0.8 1.2 1.6 2.0 2.4 2.8 3.2 feed- Weekly feed-out rate from the silo face (m) Some further considerations 20 Summer consumption Winter consumption 16 Silo fa visibly moulde (%) Minimum feed-out rate ed 12 Good silo management practices! 8 ace 4 0 00 0.0 0.5 05 1.0 10 1.5 15 2.0 20 2.5 25 3.0 30 3.5 35 Weekly removal rate from the silo face (m) Strategies to prevent aerobic deterioration at farm level Packing down fresh forage when filling the silo Oxygen barrier films to cover silage Weigh down shoulder and top sheets Additives and inoculum types Type of plastic cover: Oxygen barrier films (temperature profile) Barrier film (120 m) PE film (150 m) Maize silage: summer consumption 1 26 18 cm/day = 1.26 m/wk See Poster no. 66 (Borreani and Tabacco) Weigh down shoulder and top sheets gravel (150 kg/m2) tyres (30 kg/m2) Maize silage: summer consumption 15 cm/day = 1.05 m/wk Silo wall and packing density effect Maize silage: summer consumption 17 cm/day = 1.19 m/wk feed- Seasonal recommended feed-out rates (m/week) in dairy areas around the world Latitude Winter Summer The NetherlandsVissers al., 2007) ( et 51°N 1.00 1.50 North Dakota(Schroeder,, 2004)) (Sc oede 00 47 N 47°N 1.05 1 05 2.10 2 10 Italy 45°N 1.05 1.60 Wisconsin and Pitt, 1993) (Muck 44°N 1.10 2.10 Kansas(Berger and Bolsen, 2006) 38°N 1.35 2.15 Israel (Weinberg, 2003) 31°N 1.40 2.10 feed- Recommended silage feed-out rates in relation with environmental temperatures Week feed-out rate (m) 2.5 Present survey 2.0 International data 15 1.5 kly d 1.0 2 R = 0.84 0.5 -10 -2 6 14 22 30 (° Seasonal mean temperature (°C) co c us o In conclusion • silages, This study on maize silages underlines the importance p g g feed- of coupling high feed-out rates with careful silo management in order to control aerobic deterioration • Defining the correct size of silos at farm level is the main factor that could prevent aerobic spoilage • The i t l temperature seems t b th Th environmental t t to be the driving factor in sizing silos for different areas and seasons Thank you for your attention!
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