Dairy producers could improve rumen health of their cows by feeding high fibre grass with easily digestible cell walls suggested Johnny Bax, international technical support manager for Biotal, speaking at a briefing in Lancashire last week organised by grass seed breeders DLF Trifolium.
Feed the rumen fibre to keep it healthy, says Johnny Bax.
Mr Bax admitted that a rumen is a complex organ and not completely understood. None-the-less keeping this part of the cow in good working order is essential for profitable milk production.
“Keeping a rumen healthy boils down to maintaining a balance of the right kind of bugs, which break down the fibrous cell walls of forages. This then allows other organisms to access the nutrients inside,” Mr Bax explained. “To help with this, plant breeders are now producing grass varieties whose cell walls can be more easily broken down.”
Feed quality of grass
Producing digestible grasses has been a primary goal for grass breeders DLF Trifolium for some years.
“Farmers should judge grass varieties in three key areas,” said DLF’s agricultural sales director Tim Kerridge. “Yield of dry matter and energy, field performance, and feed quality.
“Farmers can find a lot about the first two in the Recommended Grass and Clover Lists, produced each year from trials carried out by NIAB. But the feed quality data is limited. So we have looked in detail at the nutritional characteristics of all the rated varieties at our trials site in Worcestershire.”
In 2009/2010 values were gathered for four key nutrients: water soluble sugars which are found within the cells and rapidly digested by cows, protein, grass fibre which contains slowly digested structural sugars, and cell wall digestibility.
The results showed that so called ‘high sugar varieties’ tend to be low in protein and often lower in cell wall digestibility.
“Further trials have shown that for every 1% increase in cell wall digestibility, 0.25.litres more milk per cow can be produced each day,” Mr Kerridge said. “This is because more of the nutrients in the feed can be accessed by the rumen bugs.
“Fibre promotes cudding and the production of saliva which keeps rumen pH ideal. Where farmers feed a lot of concentrates, it is vital to feed grass with a high fibre content and good cell wall digestibility to prevent acidosis.
While important to consider the dietary contribution of different grasses, it is also vital to select species and varieties that will perform successfully in the field.
“Essentially site and climate dictate the output from any grass sward,” said Rod Bonshor, general manager for Oliver Seeds.
“On good soil with adequate rainfall, there is no doubt that perennial ryegrass is the most productive and nutritionally beneficial grass for dairy cows,” he said. “But the recent cold winters and very dry springs experienced in some areas, mean it may no longer be the first choice variety for everyone.”
He went on to say that in wetter, cooler areas, Timothy, which shows strong early spring growth could be a good option. In areas experiencing drought, new varieties of cocksfoot and meadow fescues would be worth considering, as well as new crosses like festuloliums, originally bred for the Mediterranean but proving popular on farms here.
“There seems to be a real west/north, south/east divide in terms of grass growth,” said Mr Bonshor. “The seeds mixtures being grown on farms in these areas are starting to look very different.”
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