Effect of variety and harvest date on nutritive value and ruminal degradability of ensiled maize ears

ABSTRACT

The nutritive value of whole crop forage maize is influenced by the proportion of ears and stover in the whole crop and by the nutrient composition and digestibility characteristics of the plant parts. An experiment investigating the impact of variety, harvest date and year on the nutritive value of ensiled maize ears was carried out in three consecutive years (2007, 2008 and 2010). Nine different maize varieties were harvested at three different maturity stages (50, 55 and 60% dry matter (DM) content in the ears). After harvest, ears and stover were ensiled separately and afterwards nutrient composition and ruminal nutrient degradability (organic matter (OM), crude protein (CP) and non-fibre carbohydrates (NFC)) were analysed. Variety had a significant influence on content of CP and effective ruminal degradability (ED) of OM at low passage rates, whereas ED of CP and NFC was not affected by variety. In contrast, harvest date and year significantly influenced nutrient composition and ruminal degradability of ensiled maize ears. The content of NFC increased and the content of fibre components as well as ED of OM, CP and NFC declined with processing maturity of the maize plants. At a passage rate of 5% h⁻¹, ED of OM declined from 75.9% to 68.4%, ED of CP from 82.5% to 73.8% and ED of NFC from 88.0% to 82.3% between the early and late harvest date. The results of this study indicate that the nutrient composition and ruminal degradability of ensiled maize ears are affected mainly by maturity stage at harvest and by year, whereas variety has only little influence.

KEYWORDS:

• Harvest date
• maize ears
• nutrient content
• rumen degradation
• varieties

Acknowledgements

We want to thank Franz Kastenhuber as well as the experts from the Austrian Chamber for Agriculture and the Austrian Agency for Health and Food Safety for technical and material support of the investigations and the Zentralanstalt für Meteorologie und Geodynamik for supply of data on weather conditions.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

We thank the Austrian Ministry of Agriculture, Forestry, Environment and Water Management for financial support of this project.