How to minimise any quality problems with baled silage

One not infrequent problem encountered on livestock farms is of the balewrap film splitting after wrapping the bale. This can occur weeks and even months after the wrapping was done. This is most likely to occur with heavy bales of low DM silage made during broken weather conditions. Unless these bales have been carefully wrapped with a quality balewrap film they are quite likely to burst after handling, transport, stacking or during storage.

Many silage contractors and farmers immediately blame the film, thinking inferior quality is to blame for the splitting and sometimes balewrap quality can be the problem. The high tensile strength and tear resistance of the silage film is important as is puncture and tear resistance. Film elasticity, tack or cling capacity are also important as is the UV light inhibitor used to protect film from degradation during storage.

A quality brand such as Silotite Pro offers superior strength, puncture resistance, elasticity, UV stability and a double sided cling. Silotite is manufactured using the latest 7 and 9-layer patented extrusion technology. With Pro film technology the individual film layers are compacted together through heating, stretching and conditioning. Other brands usually have only three layers of film so they cannot offer the same level of protection for your valuable silage crop

However, the reason the film has split can also due to there being insufficient film cover in places on the bale (see attached photo). This is often difficult to accept, as many silage contractors believe they are applying enough turns to the bale to achieve full bale cover, with four film layers and a minimum 50% over-lap of the film layers. However many silage contractors employ young and inexperienced operators who may not carefully follow the machinery manufacturers guidelines.

Before baling, it is always a good idea to lift and spread the grass with a tedder or a rake. Ensure the swath is the same height and depth across the full width when entering the mouth of the baler – this ensures production of firm and well-shaped bales. This results in heavier but fewer bales per acre, thereby reducing costs. In addition, well-shaped bales are easier to wrap properly and to handle without causing damage.

It is very important to avoid pick-up tines disturbing the soil, otherwise crude ash can cause contamination in the bale. This can result in the increased presence of harmful organisms which can have potential health implications for livestock consuming this material. If slurry is not incorporated into the soil ideally using a shallow disc injector there is a risk of risk contamination with harmful bacteria.

Machinery Manufacturers Balewrapping Guidelines

All bale wrapper manufacturers recommend the following guidelines: 1. Count the number of turns required to completely cover the bale 2. Add one extra turn (to compensate for the narrowing of the film from the start of the cycle, when the film is held in the cut and catch mechanism) 3. Multiply this number by 2 for 4 film layers or by 3 for 6 film layers.

Note that the ‘extra’ turn is added onto the first number, when the bale is covered the first time and not at the end of the calculation. If the bale diameter is slightly more than 1.2m, the diameter becomes greater, which affects the accuracy of the 50% over-lap target. In this instance, more turns will be required to ensure full and complete coverage of the bale. Please note, it takes half a turn (two sides of the bale) for the balewrap film to open up to its full width on the bale.

When wrapping big square bales, irrespective of crop type, the bale should be wrapped as if applying 6 film layers. Unlike a round bale, which maintains the same position on the balewrapper as it rotates and provides a uniform shape for the film to be applied to, the position of a square bale is constantly changing as it turns on the balewrapper. Because of this, the bale should be wrapped as if applying 6 film layers to the bale – this is the only way to ensure there are four layers of the balewrap everywhere on the bale.

Potential Pre-Stretch Unit (PSU) Problems on the Bale Wrapper

The PSU on the bale wrapper is calibrated, through the gears, to stretch the film between the paired rollers by 70%. This is to ensure the film width over-laps by the required 50% over-lap. However, there is the possibility that the film will also stretch between the rollers and the bale, when the film will ‘neck-down’ more than it should, which will affect the % over-lap of each film layer application to the bale.

This can easily be checked by measuring the width of the last film application on the end of the bale. The correct film ‘neck down’ for 750mm wide film neck-down should be 580-600mm. (see graphics as show by Tama) If secondary stretch occurs, it will increase film ‘neck-down’ and reduce the amount of over-lap between each successive film layer, creating areas on the bale with less than the required number of layers.

If the PSU rollers on the wrapper are dirty or sticky, dirt and crop debris can easily become stuck to the rollers, causing damage to the film as it passes over them. It is not necessary for the film to have been punctured to cause it to break, often the smallest piece of dirt or debris can create a weakness in the film as it is being stretched that will cause it to fail.(see photo as per Tama)

Areas of the bale with less than the minimum required are difficult to see on black bales. The part of the bale with fewer film layers will eventually split either through weathering or as the bale settles in the stack. Sometimes the wrapping is so in-correct that only a single layer covers the bale in some places. This may be due on occasions to inexperienced operators not following the manufacturers advice on Balewrapping.

If the PSU rollers are sticky with film tack residue, the film will begin to stick to the rollers, causing ‘secondary-stretch’, which will reduce the film width being applied to the bale. So to avoid this problem, PSU rollers should be cleaned regularly, by rubbing vigorously with a cloth soaked in a solvent based cleaner. If the PSU has rubber coated rollers, it may be necessary to clean the surface then rub down with a hard wire brush, to create a grip on the rollers.

New Developments in Balewrapping

The relatively new Film & Film (F&F) system is an innovative dual wrapping method, which combines the use of SilotitePro balewrap and Baletite netwrap replacement film. The bale is effectively cross wrapped so the overall film protection is much improved. Please check out video at https://www.silotite.com/film-and-film-wrapping/

This results in better shaped and more compact bales which can better withstand handling and have a longer storage life. Using baler film instead of netwrap the F&F wrapping system helps to reduce silage losses virtually eliminating mould growth and preventing silage becoming enmeshed during feed out.

By using film to bind the bale together, removal and recycling of the film is made easier as the farmer is only left with one product to recycle and can avoid the time consuming job of separating netwrap from the stretch film.

Baletite enhances the ensiling process and protects the contents of the bale by creating additional layers of protection around the bale. It provides an air barrier that helps to prevent the growth of white mould, which can cause valuable silage losses. Using Baletite as an alternative to netwrap results in better shaped bales, by exerting a tighter grip around the bale circumference.

Excellent trial results have been obtained in Wales by Dr. Dave Davies of Silage Solutions Ltd, who acts as an independent consultant to the Silage Advisory Centres. Dr. Davies is a former Senior Research Scientist at the Institute of Grassland & Environmental Research (IGER) at Aberystwyth in Wales.

On a trial he conducted on a commercial farm in Wales under real working farm conditions. Dr Davies demonstrated that Film & Film wrapped bales had:

- 7.5% less dry matter (DM) losses compared to netwrap bales due to an enhanced fermentation process.

- 80% less DM losses compared to netwrap bales due to mould formation on the bale.

- The reduced losses that resulted through the use of the F&F wrapping system meant that the farmer on this farm gained more forage to feed to his herd. For a dairy farmer, preserving forage more successfully could provide a significant financial benefit as follows:

· This farmer gained an average of 7.35kg DM per bale using the Film & Film wrapping system.

· As 1kg of DM = 11.8 MJ ME (Metabolisable Energy), this means that the farmer gained 86.73 MJ ME per Film & Film bale (7.35 kg DM x 11.8 MJ ME).

· In order to produce 1 litre of milk you need: ± 5.8MJ/litre MJ ME.

· Therefore the 86.73MJ ME averagely gained for each of these bales could give an additional 15 litres of milk production

· For a cattle farmer this was equivalent to an increase of 1.9kg of live weight gain per bale.

It is important to note that the above trial was undertaken under commercial farm conditions and not on a research institution farm where bales are carefully handled and stored under ideal conditions by well-trained research staff.

Bales wrapped using this system also have a longer storage life, are easier to handle or stack. The value of the extra silage conserved is around £4.40/€5 per bale.

This calculation is based on data supplied in December 2022 by Dr Tom Butler of FBA Laboratories