Sometimes mould forms in a bale. Feeding mouldy bales to the cows involves a potentially high risk. “A small patch of mould is not a big issue, you can cut it out of the bale. But if there are several mouldy patches, it’s best to cut your losses and get rid of the affected bale,” says Sjon de Leeuw, management and strategy consultant at PPP Agro Advies. “But prevention is better than cure.”
There are various factors that can cause mould to form in bales. The main cause is air penetrating into the bale. Crude ash in the bales also creates a risk of mould. De Leeuw: “And when the composition of the bale is not homogeneous, for instance because wet and dry grass have been mixed, mould formation is inevitable.”
Measures to prevent mould start at harvesting. The mower must be set properly to avoid crude ash in the grass. The same applies to the tedder, rake and baler settings. “If a contractor does a good job and bales, binds and wraps the crop in the right way, any risk of mould formation is already reduced during an early stage of forage production,” says de Leeuw. “Subsequently, it is essential to ensure the bales are stacked in the right way in the right place. Measures taken to prevent air entering the bales through holes caused by birds, for example, will further reduce the risk of mould.”
Feeding mouldy bales is the same as feeding toxins
“In general, farmers have difficulty throwing feed away. But that is my advice if you find a mouldy bale. Should you decide to feed your animals a mouldy bale, what you are basically doing is feeding them harmful toxins. Those toxins can cause rumen acidification, reduce milk production and lead to issues with hoof health and weakened immunity. If you delay taking action until you have to cull cows, you are much too late. Prevention is better than cure.” advises de Leeuw.
De Leeuw: “Feed losses translate to a higher cost price. If something went wrong during the harvesting process or the bale was damaged during storage, there is a high risk of mould. On average, you can expect a €0.01 feed loss per kilogram of dry matter. So, as you can imagine, the damage caused by mould can be considerable. But my strong advice is, if you discover mould in the bales, accept your losses as the financial damage will always be less severe than having sick cows. If you feed poor quality rations that €0.01 per kilogram will soon multiply and cost you dearly. And that will make the cost price far too high.”