Water damaged fodder
Feeding livestock water damaged fodder
Animal Health Field Services - February 2011
Authored by Frank Mickan and Robert Suter from the Victorian Department of Primary Industries.
After a flood event, it is essential that good nutritious feed is provided to livestock in flood affected areas, particularly to pregnant and young animals which are less able to tolerate stressful events. However, the availability of feed can be compromised, so you may need to begin by feeding water damaged fodder.
This fact sheet describes options for and the risks associated with feeding water damaged fodder to livestock.
Affects of water damage on feed
Bales which have been inundated by water will be sodden due to seepage into the baled material; despite being wrapped in four layers of plastic.
Inundation with water leaches the preservation acids contained within the bale allowing air to enter rapidly and silt to deposit within. The pH will rise and undesirable bacteria will multiply in the air resulting in decomposition.
Signs of water damaged silage include bales that are black, are oozy or slimy and have an odour.
Silage bales that have been inundated, but not moved, by water may be salvageable. By feeding whole bales of water damaged silage to livestock, the animals can freely choose the unaffected portions of the bale.
If a stack has been partially inundated and safe access is possible, it may be possible to move the unaffected upper section of the stack to another site. Once moved the silage needs to be rerolled and resealed. This must be done quickly to minimise further losses.
Some portions of shedded and unshedded hay stacks may be salvageable if they are readily accessible and alternative 'dry' sites are available.
Hay inundated with water poses a serious risk to the health and safety of both humans and animals. Wet hay, particularly that at the bottom of hay stacks carries a high risk of spontaneous combustion (self-ignition), or of collapsing under the pressure of bales above them as the bottom ones rot.
The residual moisture will 'wick' its way up into the drier bales immediately above, spoiling them.
If possible, consider removing the upper drier bales to a suitable site. Ideally, move suspect bales (wet bales, bales subject to 'wicking' or outside stack bales exposed to rain fall) to another site. Alternatively, put these on top of the drier bales, allowing any heat build-up to dissipate whilst redrying.
These new stacks need good ventilation plus protection from further rain.
The top layer or two of large rectangular stacks, will need to be kept separate from the drier bales further down. The outer rows of bales exposed to prevailing winds and heavy rains will most likely need to be considered 'suspect' and removed.
Bales at the bottom of the stack that have been inundated with water must be moved to avoid collapse and or spontaneous combustion.
Handling and moving wet hay has a high human health and safety risk. It should only be attempted when access to the hay is good, the correct equipment is available, and a suitable alternative dry site is available.
Feeding livestock water damaged fodder
Given that water, silt, manure and possibly some dead animal tissues will have entered the silage bales and stacks, the risk of contamination by soil and carcase-born botulism bacteria may be quite high. An outbreak of deadly botulism is a possibility under these conditions, although not commonly experienced.
Silage showing signs of mould must not be fed to sheep, horses or pregnant stock. Ideally, it is best practice not to feed mouldy silage to any stock. However, if no other feed source is available it can be fed to healthy livestock of other classes as a last measure. Mouldy silage may lead to decreased production and weight loss either due to reduced intake, liver damage or through reductions in the feed quality as a result of the spoilage.
Moulds develop easily on hay that has been damaged by water, especially in warm weather. Moulds can dramatically decrease the nutritive value and palatability of the stored feed. Some moulds are toxic and may cause sudden death or longer-term health problems such as liver damage.
If potential toxicity is a concern, mouldy feeds can be sent for testing but is costly and has a reasonably long time lag.
If livestock need addition grain to balance the hay ration use mould free grain if available.
For farmers using a mixer wagon, there are several products which are designed to 'absorb' moulds and toxins. Speak with company representatives before embarking on this alternative.
Bales which have been covered by water for many days will most likely be starting to rot and very difficult to move with normal hay moving equipment. Remember that spontaneous combustion is a significant concern.
Talk to your private veterinary practitioner, DPI staff or your livestock consultant about managing a feed program for flood affected stock.
What are the signs of toxicity?
There are a number of indicators that your livestock may be suffering from toxicity. Indicators of toxicity may include:
- weight loss or stomach pain
- poor appetite, sometimes with a scour
- photosensitisation (swollen, red ears, muzzles and white skin that dries, cracks and peels)
- enlargement of the abdomen
- sudden death
Sometimes affected animals can have neurological signs such as tremors, wobbliness or convulsions. Mouldy hay may also cause abortion in pregnant animals.
Botulinum toxin causes animals to lose muscle tone, and to sit down and be unable to rise or eat or drink. They can appear normal otherwise.
What do I do if I suspect my stock are showing signs of toxicity from feeding water damaged fodder?
Seek veterinary advice through your local veterinary practitioner or DEDJTR Animal Health staff immediately.
Remove the suspect fodder immediately and provide a good quality replacement.
Subsidies may be available to cover the costs of testing - contact DEDJTR Animal Health staff on 136 186.