Maize digestibility

Published 13 February 14

Maize digestibility

It’s important to consider the changes taking place in the maize clamp at this time of year and their possible effect on cow health, stresses DairyCo extension officer, Tom Goatman.

Following on from the piece on the effect of time on maize digestibility in Forage for Knowledge 27 September 2013, there are further issues to consider as you feed out maize, which could have been in the clamp for over four months now.

The starch in maize is found in a matrix with prolamin, a storage protein in the plant. Storage increases the length of time for proteolysis (protein breakdown) to occur, degrading the prolamin and making the starch more available to the rumen. 

Due to the elapsed time since ensiling the maize crop, the starch will be now more available to the rumen micro-organisms. This has important implications for rumen health.

Diets formulated and balanced based on a lower starch digestibility earlier in the winter may have been supplemented with additional energy to compensate. The same diet now is likely to have more starch available in the rumen causing an increased risk of Sub-Acute Ruminal Acidosis (SARA).

Important signs to look out for which may indicate SARA, include: 

  • Less than 75% of lying cows cudding
  • Less than 60 chews per cud
  • Frothy or bubbly dung
  • Dung containing undigested forage and/or concentrate
  • Presence of cud balls
  • Reduced butterfats
  • Reduced intakes.

SARA has important economic and welfare implications to the industry. In order to improve our understanding of SARA, DairyCo is involved in a three year study, which is due for completion in June 2015, investigating the condition. The aims of the study include:

  • To understand why SARA is prevalent on some farms but not on others by gaining better understanding of the management and nutritional factors associated with variation in the incidences
  • Improved understanding of the underlying mechanisms involved in the development of SARA in dairy and beef cattle
  • Identification of potential probiotics that may protect cattle from SARA
  • Development of simple non-invasive methods for monitoring animal behaviour relating to SARA that may be useful in preventing the condition.


For more information click here.