Quality in quantity – professional hay and plant drying

A good meadow is the basis for good hay

Even the best drying method cannot significantly improve hay quality if the basis is not right. A good meadow with grasses, clover and meadow herbs is, in addition to the optimal cutting time, the most important basic prerequisite for good hay quality with a high protein content and energy density. There are around 3,000 different meadow plants in Central Europe. About 1,000 plant species are relevant for animal feeding. The plant species are basically divided into three groups: grasses, legumes, and herbs. The grasses include sweet grasses and sour grasses such as cocksfoot, golden oats, meadow fescue and meadow foxtail. Due to their high protein and mineral content, clovers are among the most important sources of animal feed. The most important examples of the clover species - which as a subfamily of the papilionaceous plants come from the legume family - are red clover, white clover, horn clover, Persian clover and Alexandrian clover. In the third large group, namely herbs, a distinction is made between herbs, weed plants and weeds. With herbs in particular, care must be taken to ensure gentle drying in order to preserve valuable ingredients such as essential oils, tanning agents, flavanoids, saponins and bitter substances. Here, we recommend a drying process using a heat pump, as the drying air can be adjusted very precisely to the existing herb temperature.

Good drying begins with the haymaking

During haymaking on the field, the tedding and raking must be done properly. This is true for the respective point in time, and for the speed or rotational speed settings. Studies by Kassel University show that the optimal speed for tedding and turning is 6 to 7 km/h. Too many turning operations increase flake losses and reduce the dry matter. With each turn, approx. 8 to 10 % of the dry matter is lost. If the cuttings have a dry matter content of 85%, over 16% of this dry matter can be lost through raking. In order to protect the turf, avoid fodder contamination, and significantly reduce losses, the cuttings should not be cut deeper than 7 cm from the ground. A further advantage with sufficient stubble height: The cuttings do not lie directly on the ground and can therefore dry better and faster. This is particularly relevant when the ground is damp.

Water content evaluation of hay

Pre-drying (wilting) in the field is important

Freshly cut green fodder contains about 80% water, i.e. only 20% dry matter. After a day of drying under the sun in the field, the water content is still about 40%, i.e. the dry matter content is about 60%. With a dry matter content of 60% to 70%, the wilted grass can be carried into the drying box or hay box.

Moisture development during field drying

Proof of good hay quality

Colour, odour, structure, degree of soiling and energy concentration: The Bavarian State Research Centre for Agriculture (LfL) has established clear criteria for assessing hay quality. High-quality hay has an olive-green colour (light green to dark green), has an aromatic odour (no burnt odour, no other type of odour, not musty) and contains leaf parts (corresponding to the original material). In order to judge the success of preservation, the best fodder quality of the green cuttings is assumed, with deductions made according to the following evaluation.

* Values apply to field-dried hay.

In the case of aerated hay, the losses are lower by 0.2 to 0.3 MJ NEL/kg DM

ME = metabolic (utilisable) energy

NEL = net-energy lactation (lactation = milk production)

Hay as an economic factor

Be it through insufficient or incorrect hay drying: Year after year, many tonnes of hay can only be used as litter because it is too inferior for use as animal feed. Hay drying in round bales also plays a role in this problem. Basically, the hay quality achieved by loose drying is not possible with round bales. This is mostly down to the unequal counter-pressure conditions within a bale ("cushion"). In addition, the fans used for round bale drying must generate a higher pressure than for loose hay. This results in greater energy consumption and higher costs. An additional cost factor: If the quality and quantity of hay is reduced, farmers need more concentrated feed and protein concentrated feed as an alternative. This also shows that investing in a modern hay drying plant pays off in the long run.