Protocol for cleaning of on-farm storage silos

On farm storage of feed in vertical silos or bins, is the most common form of dry-feed storage. The storage of feed in silos is subject to large fluctuations in both temperature and humidity within the silo and this leads to condensation forming on the inside of the silo from time to time. Both feed and feed dust will stick to the side of the bin, absorb the moisture and build up over time. This feed will deteriorate with mould developing and subsequent mycotoxin production becomes a serious risk. When the spoiled feed falls off into good feed, consequences for the animal range from feed refusal to mycotoxicosis. To avoid these problems occurring, silos need to be cleaned at least once a year and preferably every 6 months.

There are two types of cleaning – firstly, a dry clean and secondly a wet clean, with the latter being the preferable and more effective option, however dry cleaning is a better option when the silo boot cannot be removed easily or it is too dangerous to attempt wet cleaning.
 

Dry Cleaning

1. As with wet cleaning, safety is the most important consideration and any attempt to climb up any silo requires suitable safety equipment. Suitable protective clothing including gloves, eye protection and masks should be worn at all times. A dry clean will produce dust that is potentially harmful so care should be taken to avoid breathing in dust. safety harness with suitable anchor points is also essential equipment.
2. Dry cleaning is typically used where the silo boot cannot be removed easily or it is too dangerous to attempt wet cleaning.
3. A high pressure air blaster with a long enough hose is required – do not attempt to carry heavy equipment up the silo.
4. Disconnect the cross auger from the feed hopper in the shed and direct this into a suitable waste container so any waste residue can be removed efficiently from the base of the silo.
5. For large lumps of feed on the side of the silo, a long lightweight pole can be used to dislodge these prior to air cleaning. An aluminium pole usually used for swimming pool brushes works very well for this. Attach a safety cord to the pole and fix this to a suitable point at the top opening of the silo. This will allow you to easily retrieve the pole if it accidentally falls into the silo.
6. Using the air blaster working and from top to bottom of the silo, blast off as much of the feed stuck to the sides as possible.
7. Once the silo is clean, a light spray with a liquid mould inhibitor is useful. Alternatively dust the inside of the silo with a dry mould inhibitor product.
8. Ensure that any old feed is removed from the base of the silo and disposed of.
9. Replace the cross-auger outlet to empty back into the shed hopper.
10. Ensure that any feed residue blown out of the bin is collected and safely disposed of.
11. Test that all is in working order before filling the silo with feed.
     

Wet Cleaning

1. Safety is the most important consideration and any attempt to climb up any silo requires suitable safety equipment. Suitable protective clothing including gloves, eye protection and masks should be worn at all times. A safety harness with suitable anchor points is also essential equipment.
2. Ensure the weather is suitable to allow the silo to air dry after washing.
3. A high pressure water blaster with a long enough hose is required – do not attempt to carry heavy equipment up the silo.
4. The boot at the base of the silo needs to be removed prior to a wet clean. If this cannot be achieved then a dry clean would be the alternative option.
5. Once the boot has been removed, cover any electrical fittings that may be exposed and ensure that there is sufficient drainage below the silo to allow feed waste to freely be rinsed out of the silo.
6. For large lumps of feed on the side of the silo, a long lightweight pole can be used to dislodge these prior to washing. An aluminium pole usually used for swimming pool brushes works very well for this. Attach a safety cord to the pole and fix this to a suitable point at the top opening of the silo. This will allow you to easily retrieve the pole if it accidentally falls into the silo.
7. Using the water blaster and working from top to bottom of the silo, rinse off as much of the feed stuck to the sides as possible.
8. Once feed has been removed from the sides, use a suitable commercial grade detergent to wash the inside of the silo.
9. Rinse the inside of the silo thoroughly once washed.
10. Use a suitable disinfectant (such as Virkon®) once the silo has been washed and rinsed, and allow this to dry. A foaming disinfectant with suitable surfactants would be most suitable.
11. Once the silo is dry, a light spray with a mould inhibitor is useful. Alternatively dust the inside of the silo with a dry mould inhibitor product.
12. Ensure that the boot is also washed, cleaned and disinfected prior to re-fitting it to the silo.
13. Once the silo and boot are both thoroughly dry, replace the boot onto the base of the silo ensuring that all seals are in place and are in good working order.
14. Ensure that any feed residue washed out of the bin is collected and safely disposed of. Do not allow feed residue to be washed into storm water systems.
15. Test that all is in working order before filling the silo with feed.