Glossary Maturity class
This reflects on how long it takes the plant to achieve 30-35% dry matter. An earlier variety will have a shorter growing season and a higher maturity class number. Alternatively, an FAO number can be used, indicating the number of heat units required to reach maturity. The lower the number, the less heat units required. CWD Cell wall digestibility gives a value to the rest of the plant that isn’t starch – the leaves and stem (making up 45-55% of the plant). Usually expressed as a percentage, converted into a 1-10 number, each unit corresponds to a 1% increase in cell wall digestibility. This 1% increase can increase dry matter intake by 0.17kg/day. ME Varieties with high ME will be more digestible. This will pass through the rumen quicker increasing consumption and production levels. Lower ME levels take longer to process and are slower through the rumen. This is particularly important for rations with a high maize content. Starch This provides the link to cob maturity in the plant. Varieties that are ‘early’ will have more chance of reaching cob maturity, and more starch, than later varieties. High starch varieties are important in rations with low maize percentage. Maize provides a good source of starch with less risk of acidosis than cereal starch as it has slower fermentation rates. Agronomic factor Total sum of factors – including early vigour; standing power; leaf senescence and eyespot. All values based on an average for both favourable and less favourable sites.
05 Maize Handbook 2020
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