High Sugar Grasses

The term high sugar grass (HSG) refers to diploid perennial ryegrass varieties which have been bred for an elevated level of Water Soluble Carbohydrate (WSC). These grasses have a large proportion of their ME (metabolisable energy) as plant sugars which are readily metabolised in the rumen.

Should I grow HSG?

When selecting any ryegrass, there are some critical issues to consider when matching a pasture variety to the dairy farm. The factors are listed in order of importance:

Endophyte type and seed infection level (this is particularly important in areas with high challenges from pests such as black beetle where AR37 is best for reducing damage)
Heading date: this influences early spring growth and should complement the heading dates of other ryegrass pastures on the farm.

If after making this analysis, an HSG is seen as appropriate, consider:

Expected total dry matter production
Herbage quality.

Although high WSC is a trait relating to quality it is not possible to consider its merits in isolation; some of the potential impacts (both positive and negative) of perennial ryegrasses with high WSC may be indirect ones. There is a complex interaction operating which may cause changes in pest resistance, nutrient cycling and decomposition, pasture composition and diet selection.

These issues are every bit as significant as the proposed changes in N utilisation, DM intake and milk yield responses. It is important to consider this when selecting a ryegrass.

For more information: