For a number of years, the DSV breeders have not only selected for yield, disease resistance and
other traditional criteria, they have also analysed the most important forage quality parameters.
DSV has taken a new step forward in forage grass breeding, with all varieties being tested for
digestibility of organic matter, crude protein, water soluble carbohydrates (mainly sugar), cell
wall fraction, digestibility of cell wall and ash content.
How does “Milk Index” work?
All high-quality forage varieties or mixtures are easily identified by the “Milk Index” (MI)
symbol. Varieties marked with this symbol are not only tested by DSV: Milk Index varieties offer
outstanding forage quality based on the NIAB list for recommended grass and clover varieties and
other independent European institutes. Since a long time forage quality already forms part of the
NIAB evaluation process in England and Wales. It is a very important aspect of variety
recommendation there. Since the forage quality of grasses has been attracting a lot of attention
all over continental Europe as well, it may become part of the official recommendation there
What benefits does it offer to farmers?
Forage quality has been essential for British farmers for many years. The forage quality of
grasses has been an essential aspect of variety recommendation in England and Wales for a long
time, with official tests examining the following parameters:
d-value midsummer (digestibility under simulated grazing management)
d-value 2nd conservation cut (digestibility of the second silage cut in the first year of
According to NIAB, the official institute for variety evaluation in England and Wales, trials
have shown that
animals eat more grass of a variety with a high d-value (digestibility)
in situations, when enough forage is available, higher digestibility has a huge impact on
Delayed harvest with AstonEnergy – higher yields, still good
The yield and quality (digestibility) of grass at the first silage cut in May is largely
determined by the heading date of the variety or varieties in a mixture. Even within one ripening
group the earlier ones tend to have a higher yield, but lower quality than those heading at the
end. Later heading varieties within the group can therefore be cut later and still produce good
quality silage. Yield will also increase. Data from official NIAB trials in the UK, and own DSV
trials, have shown the effects on yield and quality of different varieties when cutting is delayed.
AstonEnergy has shown that when the cut is later, the yield increases, but forage quality still
remains on a high level.
The timing of the first cut can also have an effect on the yield and quality of the second
silage cut. Weather conditions also play their part, but the genetics of the variety have a very
significant effect. The DSV trials have shown that the yields of the second cut were almost
identical, but there were big differences in quality when the first cut was done earlier or later.
The second cut digestibility of the trial cut earlier at the first cut was nearly 4 % lower
than the later cut trial. In both trials AstonEnergy had the highest digestibility.
Methane emission from dairy cows contributes to global warming. The production of methane (CH4) in rumen fermentation also represents a significant loss of dietary energy for the
dairy cow. Therefore, reducing methane emissions from dairy cows has environmental as well as
Scientific research and model calculations have shown that improving the forage quality of
grass by means of a lower cell wall fraction and increased digestibility could contribute to
reducing undesirable methane emissions from dairy cows.
For many years, DSV has continuously analysed the dry matter composition and digestibility of
registered varieties and new candidates. These analyses enabled the selection of specific perennial
ryegrass varieties with consistent higher digestibility compared to other tested varieties.
Quality results from forage trials conducted at different locations confirm the high
digestibility of the Milk Index variety AstonEnergy. This high digestibility not only enables a
higher milk production, but also lowers the methane emission. AstonEnergy distinguishes itself from
other varieties by lower cellulose and hemicellulose fractions, in addition to an above-average
digestibility. A model calculation demonstrates that this quality profile results in lower methane
emissions from rumen fermentation. Calculated reductions in methane losses for AstonEnergy compared
to other tested varieties vary between 4,6 % for a ration composed of grass silage, maize silage
and concentrates up to 8,4 % for a grazing ration of grass and concentrates.
Conclusion: Is digestibility of forage (D-value) one unit better, a cow gives 0,2 l -
0,25 l* more milk per day.
Calculation feeding quality:
When grass silage/fresh grass of AstonEnergy (unlimited intake) is given, then a dairy cow will
produce additional 0.75 l milk per day compared to a dairy cow, fed with silage, which is produced
out of all other tetraploid intermediate perennial ryegrasses (without hybrids and AstonEnergy).
Calculated for a 305-days-lactation of a dairy cow (milk giving
period): 0.75 l x 305 = 229 l.
That means for 100 dairy
22,900 l more milk are possible with AstonEnergy!
DSV varieties and mixtures with Milk Index
Initially, DSV only analysed the feed quality of perennial ryegrass, the most important forage
grass species in Europe, but a few years ago the company decided to expand its focus from perennial
ryegrass to other species in order to identify which varieties offered superior forage quality.
COUNTRY Energy 2027 Milk Index
Top-quality mixture with 100 % perennial ryegrass; only comprising high-quality forage
varieties ASTONENERGY, KAIMAN, ROSSERA and EUROCONQUEST
What is important to know about forage quality?
The forage quality of grasses is determined by different factors, which as a whole inﬂuence
palatability, digestibility and nutritive value of fresh grass or silage. High forage quality has
The ratio of protein and energy in terms of amount and synchrony in time of availability in the
rumen strongly inﬂuences the milk (protein) yield. Rumen microbes can rapidly degrade herbage
protein and, depending on the available energy, synthesize this into microbial protein which can
efﬁciently be utilised in milk protein production. To optimise the potential microbial protein
synthesis rapidly available energy in form of sugar is necessary. When this energy is missing the
rumen-degradable protein is not fully utilised in milk protein production. The rate of forage
degradation i.e. cell wall digestibility is very important for the synchrony of protein and energy
in the rumen. Once the cell wall is degraded, sugar is easily available as a rapidly degradable
source of energy. In general, due to a higher passage rate, a higher cell wall digestibility
increases the potential forage (DM) intake and as such also the animal performance.
Cell wall digestibility (DNDF) and sugar content also play a major role in silage making. The
ensiling process is based on exclusion of air (anaerobic environment) and acidiﬁcation in which
lactic acid bacteria convert sugar to lactic acid. The cell wall structure strongly determines the
availability of sugar for lactic acid bacteria. When the cell wall is highly digestible, the cell
wall is easily degraded and sugar in thecell contents can easily be reached by lactic acid
bacteria. A high sugar content stimulates an ideal lactic acid fermentation resulting in a rapid pH
reduction and consequently a high storage stability.
DSV analyses the quality parameters mentioned in the table for both new applicants and
registered varieties. The aim of the comprehensive analyses is to develop varieties with improved
performance compared to existing varieties regarding the multitude of quality parameters.
Why did DSV introduce this brand?
Identification of the high feeding quality variety is much easier, for farmers and dealers as
In future feeding quality will be very important in grass breeding, right next to yield,
disease resistance or sward density.
In maize it is already an important parameter in feeding and breeding
COUNTRY farmers experiences
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