Fermentation reduces feed value and palatability of the dairy ration
Fresh forage contains microbes such as bacteria, yeasts and mould. It is a mixture of beneficial microbes, such as lactic acid forming bacteria and undesired microbes such as clostridia or moulds. Proliferation of microbes in silages initially leads to consumption of the oxygen trapped in the silage. Once all oxygen is consumed, growth of anaerobic lactate forming bacteria decreases the pH of the silage. This acidification results in stability of the silage.
If the balance between beneficial and undesirable microbes is disturbed or the amount of oxygen after harvesting is too high, this acidification process will slow down. This will create favourable conditions for the growth of yeasts, coliform bacteria, clostridia and moulds. These moulds can sometimes be recognized via visual inspection. The growth of these unfavourable microbes results in a bad smell and reduced palatability of the silage. This will ultimately lead to reduced nutritional value and palatability of the dairy ration.
Crop contamination with microorganisms occurs already on the field, but also before and during harvesting. Proliferation can either occur after ensiling, after opening of the silage (mainly at the cutting edge) or in the TMR once the silage is mixed into the dairy ration.