What is Aber High Sugar Grass?

Farmers using Aber High Sugar Grasses (HSG) can benefit from increased production while simultaneously helping the environment. These award-winning perennial ryegrass varieties are bred to contain higher water-soluble carbohydrates than standard grasses. This enhances protein use efficiency in livestock, ensuring less is wasted as harmful ammonia and nitrous oxide emissions.

What are the benefits?

Dairy

• Up to 6% average higher milk yield per cow (Miller et al, 2001):
• 2.7kg per day increase in milk yield in late lactation cows (Miller et al, 2001).
• Dry matter intake increase: 2kg per head per day (Miller et al, 2001).
• Diet digestibility: 3% improvement with Aber HSG vs standard grasses (Miller et al, 2001).

Beef

• Up to 25% dry matter intake increase (IBERS).
• Up to 20% higher daily liveweight gain (IBERS).

Sheep

• Up to 20% higher daily liveweight gain (IBERS).
• Up to 20% higher sward carrying capacity (IBERS).

Increase in liveweight gain (LWG) in lambs grazing Aber HSG

Timeframe	Liveweight gain change
6 May-27 May	15% increase
27 May-17 June	26% increase
17 June-8 July	6% increase

Source: Lee et al, 2001

Environmental

• 24% reduction in urinary N excretion (IBERS).
• 4-6% reduction in nitrate leaching (Soteriades et al, 2018).
• 7-11% decrease in ammonia losses to the atmosphere (Soteriades et al, 2018).
• 40% lower carbon footprint per litre of milk when combined with improved manure management (Soteriades et al, 2018).

Reduced emissions from dairy cows grazing Aber HSG

Measure	Early lactation dairy cows	Late lactation dairy cows
N in urine per kg milk	26% decrease	41% decrease
N in faeces per kg milk	5% decrease	25% decrease

Source: Miller et al, 2002; Moorby et al, 2006

How does Aber HSG work?

Fresh grass is naturally high in crude protein, but cows and sheep are inefficient at converting grass protein into milk and meat. When grazing standard grasses, ruminant livestock only capture around 25% of the available protein.

The rest is mostly wasted as harmful ammonia and nitrous oxide emissions in urine and dung. Optimising the balance between protein and energy intake is a challenge in grazing livestock systems, and one that Aber HSG has been bred to resolve.

The challenge: Inefficient protein capture

This inefficiency is caused by an imbalance between readily available energy and protein in grass, which starts when proteins are rapidly broken down as grass enters the rumen.

With livestock lacking available energy, rumen microbes struggle to use the nitrogen released. Much of the N in urine is in the form of urea, which is converted to ammonia by hydrolysis and excreted.

In standard grasses, cell walls are formed by complex carbohydrates called cellulose, hemicellulose, and lignin. While they can be broken down to provide energy, the process is too slow and out of balance with the speed of protein breakdown.

The solution: Higher-quality grass that reduces emissions

Water-soluble carbohydrates (WSC) in grass are the sugars found inside the plant cells, rather than in the cell walls. Unlike the carbohydrates in the cell walls, these sugars can provide readily available energy soon after entering the rumen.

Aber HSG varieties are bred with higher WSC levels than standard grasses. This fuels the rumen microbes to process more of the grass protein. The protein can then be used by the animal to produce more milk and meat, rather than being excreted as harmful emissions. This is why livestock perform better with Aber HSG.

Who developed Aber HSG?

A legacy of forage innovation

Germinal began a long-standing commercial partnership in 1989 with the Institute of Biological, Environmental and Rural Sciences (IBERS) at Aberystwyth University, now world-renowned as a unique base for research in response to global challenges.

AberDart was the first Aber HSG variety to reach the Recommended Grass and Clover List in 2000. Aber HSG has since won numerous prestigious awards, including two National Institute of Agricultural Botany (NIAB) Variety Cups, the Queen’s Anniversary Prize, and Innovation and technology awards from the Royal Agricultural Society of England (RASE), and the British Grassland Society (BGS).

Next-generation Aber High Sugar Grass varieties are now bred by Germinal Horizon, our dedicated R&D division, for Germinal’s Climate Smart mixture ranges, with multiple varieties featured on recommended grass lists each year in the UK and Ireland.

What do farmers think of Aber HSG?

Find Aber HSG in Climate Smart ranges

Aber HSG varieties are the backbone of our Climate Smart mixtures, with the CLEAN range specifically formulated to reduce emissions while also lifting livestock production.

Start reducing emissions and get better livestock production with Germinal grass and forage.