Nutrition

Hays are obtained by naturally or artificially drying green forages from natural grasslands or of cultivated plants, representing together with the silage forages and the roots the base ration of dairy cows in the winter season.

The nutritional value of hay is given by the composition of the flora, the age of the plants at harvest, the system and the drying duration, as well as the way of storage. Good quality hay should be of green color, with pleasant aroma, without containing dust and molds.

1. optimal mowing cutting at heights of 4-6 cm on natural grasslands, respectively of 5-8 cm on harvested meadows or combined mowing with the conditioning of mowed plants (crushing, breaking or shredding stalks) and the leaving in furrows;

2. ravishing, turning and gathering in windrow;

3. gathering from the windrow, charger, transport and unloading of hay from the storage location;

4. storing up on the hay barn or on the drying platform;

5. completion of drying through ventilation, until the storage moisture (max 18%).

The first three works belong to the first stage of drying on the stubble, and the last two belong to the second stage of drying finalization of hay ventilation.

The optimal harvest age is in the earing stage for perennial grasses, respectively in the budding phase for perennial legumes, recommending the assurance of the optimum harvesting period for ensuring a high ingestion of dry matter.

Feed green, freshly cut, contains a large amount of water, generally between 70 and 85%. The state of stability is obtained when the water content of the hay falls to 15%, when the enzymes of plants become practically inactive and when the development of fungi becomes impossible. In order to reduce the drying time and hence the loss of nutrients, there have been developed several methods of harvesting, preparation and storage of hay, such as: traditional drying (natural) on the stubble; drying on racks; fodder drying by cold air ventilation; fodder drying by blowing hot air; drying of green fodder through the thermal drying in special stations and briquetting etc.

The biggest losses of nutrients are obtained from traditional drying on hay stubble. These losses reach, in case of bad weather, even to 50-60%, the drying time increasing up to 6-8 days. The lowest losses, of 4-5% are obtained in the case of dehydration of green fodder in special stations of drying and briquetting.

The quality of the obtained hay improves on one hand by reducing the duration of maintaining on the ground of the feed after mowing, and on the other hand by the execution of works at a high quality level.

By changing the chemical composition of plants during drying on the ground depends on the enzymatic processes that occur in plants after cutting, in close correlation with the drying duration of the plants. Cut plants continue to breathe as long as the dry matter content is below 80%. The plant respiration causes losses of easily soluble carbohydrates and protein loss, particularly in the early hours of drying, by the transformation of insoluble nitrogen into soluble nitrogen, which gets transformed into amino acids and, if drying has a longer duration, even in amides.

Also, the vitamin content suffers changes, the intensity of carotene destruction being dependent on the drying duration. A slow drying (4-5 days drying on the ground) can lead to the activation of an enzyme called lipoxidase that can destroy almost entirely the carotene. An opposite result was observed in the case of vitamin D, when sterols from green plants give to naturally dried hays a more pronounced rickets activity. In the same conditions for the duration of drying, the vitamin B1 content decreases, but not the content of the vitamins B2, B5, B6 and B7.

During the course of hays preparing (mowing, drying, turning, pressing) the leaves detach from the stems, increasing nutrient losses, resulting in an increased cellulose content and a decreased digestibility.