Spoilage found on the top and sides of stacks, which can be dark and slimy or contain visible mould, should not be fed to livestock.
Studies have shown that including a small amount of spoilt silage (eg top spoilage) with mostly well fermented silage can have a detrimental effect on the digestibility of the whole diet.
There are chemicals produced by spoilage organisms which are believed to harm some rumen microbes and adversely affect both silage intake and silage digestibility.
Case Study:
The graph below shows the results of a trial conducted at Kansas State University where steers were fed either 100% well fermented silage (0), or well fermented silage with either 5%, 11% or 6% spoilt silage included.
Samples were taken from the rumens of each group of steers to measure the fibre digestibility of the total diet. Even with only 5% spoilt silage included, fibbre digestibility dropped from 63% (which equates to maintenance plus a good liveweight gain) to 56% (just maintenance).
