Producing quality hay – it’s not so simple
Hay harvesting has changed a lot in the last few years. Big bales have replaced small bales and loose storage. The composition of the types and varieties on the pastures is also different now. Varieties with high sugar content, high energy density, more yield and greater foliar mass dominate in many areas. These varieties involve a different drying process than the comparatively older varieties. Although they have more leaf mass (and the leaves dry more quickly), they also have higher sugar contents that make drying more difficult. Sugar influences the aw value by binding water. And removing the biochemically bonded water in the drying process is always difficult. The harvesting window has also become shorter. Quality hay needs stable storage in good weather – and this is increasingly rare. Furthermore, the hay doesn’t always dry evenly on the field during the traditional ground drying. High-density storage and unstable weather in particular make the process more difficult.
The problem of residual moisture
Usually the knots are the areas that contain residual moisture. After the harvest, the residual moisture seeps back into the stems and leaves. And because hay is usually pressed into square bales, it can barely escape. This in turn creates fertile ground for micro-organisms, especially mould. The result is a degradation of nutrients and reductions in quality combined with a lower hygiene status. If the drying doesn’t proceed favourably, the losses of easily digestible nutrients increase, as does the risk of mould. Mould spores irritate the animals’ respiratory tracts and can result in health problems.