Hay quality management

Independently to the problem of dry matter losses, which can be attributed to mechanical causes bound to various operations of drying and harvest or to physiological factors (breath, microbial degradation), climatic conditions during drying period can also have an influence on hay quality. For a definite feed, the progress of the drying is a function of radiation, temperature, wind speed and drying capacity of the atmosphere which is measured by water deficit. The hillside and the exposure of the plot of land are also factors which can influence the speed of drying. In conditions of normal drying, the content in dry matter of a hay of (60 %), convenient to the stocking, is reached after 2 or 3 days.

In these conditions, we suppose the quality of the produced hay is optimal for given environmental condition or hay characteristics. The presence of precipitation during this period may lengthen the period of drying in the field and increase losses bound to the washing of the soluble elements and to various necessary supplementary mechanical works to reach a normal drying of the hay.

Long stays in the field following unfavourable weather conditions also lead to an important loss of fermentescibles carbohydrates. The degradation by germs and molds also represents an important risk which cannot only be translated by losses in dry matter but can also lead to production of unwanted mycotoxins.

Considering the lossess of directly digestible compounds, drying in bad conditions produces more losses of energy value than of dry matter. For example, if bad conditions of drying can lead to losses in dry matter of about 16 %, the VEM value can be reduced of about 25 % with regard to the value of the herb at the time of the cutting.

Independently of the intrinsic quality of the herb at the time of its cutting, it is obvious that its marketing, in the form of hay, can let appear situations where the quality does not correspond to the expected value. The valorisation of differentiated quality hays in well identified zones with high floristic diversity must use a geographic traceability indicator so as to supply to customers a supplementary guarantee to valorize its animal production.

This experiment is based on an analysis which was started with Belgian user group in the frame of a pilot site in the Attert municipality localized in the Southeast part of Belgium.