Frequently Asked Questions

What is "High Sugar Grass"?

High Sugar Grass - or HSG - is the term given to new ryegrass varieties that have been bred specifically to contain very high levels of water soluble carbohydrate (sugar) These have been bred by the Institute of Grassland and Environmental Research (IGER) and carry the prefix "Aber", which denotes the origin and authenticity of the breeding. However, not all "Aber" varieties are HSG varieties.

Why has Aber High Sugar Grass been developed?

Breeding for increased quality, such as high sugar content to improve the efficiency of rumen function, is the next logical stage in the development of new grass varieties in the 21 st century. IGER's scientists discovered more than two decades ago that livestock grazing grass with a high sugar content produced more meat and milk. Forage breeders at the Institute have since worked to develop new varieties with this valuable quality trait, combined with other important agronomic characteristics such as high yield, persistency and disease resistance.

How does Aber HSG work?

Aber HSG varieties provide extra energy (sugar) for the rumen microbes, which allows them to utilise more of the available protein from grass and clover. The proportion of this protein used in meat or milk production is increased, and the amount lost via dung and urine is reduced.

Is Aber High Sugar Grass a GMO?

No. Aber HSG varieties have been developed using traditional grass breeding techniques.

What are the main economic benefits of Aber High Sugar Grass for the livestock farmer?

Extensive research has shown that HSG varieties produce measurable performance benefits for dairy, beef and lamb producers, such as:

• Improved milk yield in dairy cows (up to 20% more milksolid production shown in autumn trial*)
• Improved liveweight gains in lambs and beef cattle (up to 20% higher*)
• Higher dry matter intakes (up to 2kg/head per day*)

Are there any other significant benefits?

There are significant environmental benefits, due to more efficient use of feed nitrogen and a reduction (by up to 24%) in the nitrogen excreted into the environment. This is highly significant in the context of future farming practices. Nitrogen emissions by ruminant livestock are considerable, so any technology that can reduce overall levels is increasingly important.

Are the benefits of AberHSG retained when ensiling?

On-going research is showing that the higher levels of water soluble carbohydrate in Aber HSG varieties can lead to a higher feed value silage, particularly where an effective innoculant is used to encourage an efficient fermentation. An effective additive will promote a rapid and efficient fermentation, which drops the pH quickly and maximises the amount of sugar retained in the silage.

Is Aber HSG suitable for organic or "extensive" production systems?

Aber HSGs offer important benefits for all farming systems where producers want to maximise the use of homegrown forage in livestock diets.

How much higher is the sugar content of an Aber HSG variety, compared with other grass varieties?

The level of water soluble carbohydrate in all grass varieties varies according to the seasonal conditions and the growth period. Due to seasonal and management induced fluctuations in WSC content, comparisons cannot be made between varieties in different trials. However, research has shown that Aber HSG varieties consistently contain higher levels of sugar when compared with other varieties in the same trial.

AgResearch Report 2002

"Further work by Dr Susanne Rasmussen in late autumn 2002 on the diploid cultivars comparing total sugar content in the leaf blade and sheath separately, showed a large difference between the controls and the Aber cultivars, especially in the leaf blade".


Note: The results above show that the high sugar trait expresses very well under New Zealand conditions.

Do High Sugar Grasses like it hot?

NZ Standard ryegrasses % drop in sugar levels - Gore to Palmerston North:
AgResearch Growth Trials, 2003-2006.

Conclusion: The temperature effect is a ryegrass problem, not specific to High Sugar Grasses. The HSGs for most of the time are higher in sugar than the NZ perennials.