Lining bunker walls with oxygen barrier film reduces nutrient losses in corn silages

Abstract

The objective of this study was to evaluate 2 systems for covering corn silage in bunker silos. The first system consisted of a sheet of 45-μm-thick oxygen barrier film (OB, polyethylene + ethylene-vinyl alcohol) placed along the length of the sidewall before filling. After filling, the excess film was pulled over the wall on top of the silage, and a sheet of polyethylene was placed on top. The second system involved using a standard sheet (ST) of 180-μm-thick polyethylene film. Eight commercial bunker silos were divided into 2 parts lengthwise so that one-half of the silo was covered with OB and the other half with a ST system. During the filling, 3 net bags with chopped corn were buried in the central part (halfway between the top and bottom of the silo) of the bunkers (CCOR) in 3 sections 10 m apart. After filling, 18 net bags (9 per covering system) were buried 40 cm below the top surface of the 3 sections. These bags were placed at 3 distances from the bunker walls (0 to 50 cm, 51 to 100 cm, and 101 to 150 cm). During unloading, the bags were removed from the silos to determine the dry matter (DM) losses, fermentation end products, and nutritive value. The Milk2006 spreadsheet was used to estimate milk per tonne of DM. The model included the fixed effect of treatment (7 different locations in the bunker) and the random effect of the silo. Two contrasts were tested to compare silages in the top laterals (shoulders) with that in the CCOR (CCOR vs. OB and CCOR vs. ST). Three contrasts compared the corresponding distances of the silage covered by the 2 systems (OB50 vs. ST50, OB100 vs. ST100 and OB150 vs. ST150). Variables were analyzed with the PROC MIXED procedure of the SAS at the 5% level. The OB method produced well-fermented silages, which were similar to CCOR, whereas the OB system showed less lactic acid and greater pH and mold counts compared with CCOR. The ST method had 116.2 kg of milk/t less than the CCOR, as the OB system and the CCOR were similar (1,258.3 and 1,294.0 kg/t, respectively). Regarding the distances from the walls, the effects were more pronounced from 0 to 101 cm. The OB50 and OB100 silages had better quality and lower mold counts and DM losses than ST50 and ST100. The OB system reduced DM and nutrient losses at the shoulders in farm bunker corn silages compared with no sidewall plastic. The OB film should lap onto the crop for at least 200 cm so that 150 cm are covered outward from the wall.

Nutritive value of corn silage from intensive dairy farms in Brazil

“…The management necessary to prevent aerobic deterioration at the top of bunkers requires proper chop length, good packing, coverage with plastic, and a proper feed-out rate. Among these alternatives, the quality of the plastic film and how well it is secured to the crop are considered keys to eliminating top spoilage, as reported by Lima et al (2017). Those authors evaluated two covering systems in dairy farm bunker silos: an oxygen barrier film on the walls and top lateral compared with no wall film and a single layer of standard polyethylene film top cover.…”

“…Furthermore, to our best knowledge, no articles exist in the literature on the nutritive value of corn silage produced in Brazil at a commercial scale. Besides, when considering commercial bunker silos in Brazil, our research team has noticed that some aspects of the corn silage (e.g., color, smell, and presence of molds) have varied greatly between the upper layer (top) and the central part of the silo as a function of aerobic deterioration (Da Silva et al, 2014;Lima et al, 2017). Thus, we hypothesized that the availability of nutritional data could show which parameters need to be improved as well as help nutritionists and producers with the formulation of diets when corn silage is used as a forage source.…”

Production and utilization of silages in tropical areas with focus on Brazil

“…In addition to plastic quality, the way the film covers the silage is also important. Recently, studies were undertaken in a tropical area to examine the use of an oxygen barrier film on the walls and top regions of bunker silos compared to only a single layer of standard polyethylene film on top of the bunker (Lima et al., ). Lining the inside of the bunker walls before filling is an alternative approach to ensure a more complete exclusion of oxygen during ensiling and storage (Bernardes, ).…”

“…Lining the inside of the bunker walls before filling is an alternative approach to ensure a more complete exclusion of oxygen during ensiling and storage (Bernardes, ). Thus, the use of high‐quality plastic film and ensuring a close contact of the film with the silage surface are essential for producing high‐quality tropical silages (Lima et al., ). Placing materials on top of the plastic cover also markedly affects silage quality (Bernardes, ).…”

Feasibility of Utilizing Biodegradable Plastic Film to Cover Corn Silage under Farm Conditions

“…By the mid-1970s, the use of PE had become the conventional method of covering horizontal silos, and this practice remained unchanged for 30 years. The development of films with similar mechanical characteristics to those of a PE film, but with reduced permeability to oxygen (OB) (obtained by coextruding a layer of barrier polymer), has been shown to improve the quality of corn silage by reducing the yeast count and increasing in aerobic stability [36][37][38]. Borreani and Tabacco [9] found, in a commercial bunker silo, that the quality of the silage was improved, over the entire silo face, by use of an OB film, and spoiled silage was minimized (< 0.6% of the silo surface compared with 5.8% for the part covered with a PE film), especially in the corner areas close to the bunker walls where the DM density was lower and it is more difficult to seal the silos.…”