Assess maize degradability to maintain rumen health
Addressing ration protein and energy balance is a must this season as maize silage analysis shows worryingly low degradability figures.
At first glance maize analysis results may not appear as disastrous as initially thought following the less than ideal season. However, many producers could get a nasty surprise when they look at degradability.
Frank Wright ruminant manager Adam Clay is strongly advising producers to look carefully at maize analysis results and act to ensure cow and rumen health is not compromised.
“On average maize is nearly 12% less degradable than last year’s crop,” he says.
Highlighting the starch component of the crop as having low degradability, Mr Clay blames the fact that many producers have harvested a more mature crop which consequently has a harder starch.
“In this case, the energy from maize will bypass the rumen and be digested in the gut. This may be more rumen friendly, but it is important to ensure the ration is providing enough rumen digestible energy to utilise the protein component of the diet,” he explains.
Failure to do so will result in excess rumen protein which will reduce microbial development and leave ammonia to circulate the body.
“This ammonia will negatively affect lameness and fertility and the excess protein will “search” for energy to use, which may cause problems with negative energy balance,” Mr Clay explains.
Consequently it may be necessary to provide quick fermentable energy. This could be provided from starch in the form of wheat or barley, or from sugars from molasses.
For example, a herd feeding 10kg DMI of this year’s maize silage will need an extra 0.5kg of wheat or 0.9 litres of molasses to match rumen energy supplied from microbial development by 2011 maize crops.
However Mr Clay stresses it is essential to balance the ration in a rumen friendly manner.
“In general, maize is slightly wetter, with high potential acid loading this season. As a result, any supplementation with rumen energy must be balanced with appropriate fibre to maintain rumen health.”
Feeding wet grass silage, which will have high excess rumen protein (metabolisable protein from nitrogen), along with maize silage with lower levels of available rumen energy, will also exacerbate problems with negative energy balance.
Find out how the 2012 maize harvest went on our special page