Silage maize represents a significant source of energy and nutrients for high-producing dairy cows. Intensive breeding under conditions of pronounced climate change has resulted in a broad and dynamic range of silage hybrids entering the market.

Growers need to understand not only the characteristics of the hybrids they cultivate, but also the way in which their genetic potential is expressed under specific growing conditions. Systems for the characterisation and evaluation of hybrids have a long history; however, they are often derived from the assessment of earliness in grain maize hybridsand therefore do not fully reflect the requirements of silage maize.

This publication is based on an analysis of the nutrient composition of 140 hybrids classified into FAO maturity groups ranging from 120 to 400 in north-eastern Slovakia, and 73 hybrids classified into FAO maturity groups ranging from 240 to 600 in south-western Slovakia.

Measurements of nutrient composition (dry matter content, water-soluble carbohydrates, starch and NDF) were carried out between 2016 and 2021. Each monitored hybrid was sampled and analysed in each season at least four times during its vegetative development.

Differences in the magnitude and dynamics of changes in nutrient composition among hybrids were evaluated in relation to soil and climatic conditions, experimental sites, individual experiments and classification into FAO maturity groups.

The publication provides an extensive analysis of these relationships, documented not only in the text but also through more than 80 graphs, tables and diagrams. The outcome of this work is the definition of the concept of ‘silage maturity of maize’ and, based on these results, the proposal of a new system for evaluating the earliness of silage maize hybrids.

For practical application, a Silage Maturity Certificate for hybrids is proposed—a model ‘birth certificate’ that enables easy comparison of hybrids within the context of specific production conditions and supports the development of successful silage strategies.