Maximising maize grain digestion is important since maize grain contains 70% more metabolisable energy than stover (the green part of a maize plant). The yellow fibrous outer covering of the maize kernel (the pericarp) is one of the least digestible parts of a maize kernel. Fracturing the kernels allows the rumen bacteria access to the highly digestible starch inside the grain. Research has shown that, over 22 trials, cows fed diets containing processed maize silage produced an average of 0.5 kg more milk per day than cows fed diets containing unprocessed maize silage1.
While all crops will benefit from plant processing that breaks up maize kernels, gains are even greater in crops where the grain is mature.
Currently the New Zealand recommendation is to have 99% (with a target minimum of 80%) of the kernels broken into at least four pieces.
1Harrison J.; van Wieringen, L. 2011. Processing corn silage.