Storage of animal feed in vertical silos or bins is the most common form of dry feed storage on New Zealand farms. Silos can be a great way to store feed, as they reduce wastage and protect feed from climatic events and from pests such as birds and vermin. Silos also allow farmers to reap the financial benefits of purchasing feed in bulk and feeding it easily through in-shed feeding systems or into troughs and feed-out bins. Silos do however need to be cleaned thoroughly at least once a year, to ensure that the feed stored inside them is kept as fresh as possible. A great time to do this is just before the start of a new season.
The storage of feed in silos is subject to large fluctuations in both temperature and humidity within the silo, which can lead 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. When this spoiled feed falls off into good feed, consequences for the animal range from decreased feed intake and feed refusal due to the presence of mould (which animals can be very sensitive to the smell and taste of), right through to mycotoxicosis. This can occur when poisonous toxins produced by moulds are consumed at high enough levels to cause animal health issues. To avoid these problems occurring, silos need to be cleaned at least once a year and preferably every 6 months, to ensure that excessive mould does not build up on the inside of the silo and that feed delivered to the animal is as fresh and palatable as possible.
Farmlands has developed silo cleaning procedure that describes the best practices for cleaning animal feed silos. There are two methods to use, either a wet method or a dry method. The wet method is the most effective and preferable method for cleaning a silo, however dry cleaning is a better option when the silo boot cannot be removed easily or it is too dangerous to attempt wet cleaning. When using the wet method, using a suitable disinfectant such as Virkon® during the clean is worthwhile. Both methods benefit from dusting the inside of the silo with a liquid or powder mould inhibitor after cleaning to hamper future mould growth.
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.
The Farmlands Nutrition team has created a factsheet that explains the steps for both the wet and dry methods of cleaning silos. Visit the Nutrition section of the Farmlands website to view the fact sheet, or contact your local Nutrition Specialist or Technical Field Officer for a copy.
Article supplied by Stacey Cosnett, Nutritionist, Farmlands.