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News 1804 views last update:14 Jan 2016

Straw value for ruminants dismissed by mythbusters

Dairy cow nutritional experts have thrown out the theory that feeding cows straw is necessary for good rumen function and to regulate the rumen’s pH, as ‘completely false’.

Speaking at a DairyNZ run seminar in Temuka, New Zealand, were Dr Jim Gibbs of Lincoln University, DairyNZ animal science principal scientist Dr John Roche and Dr Terry Hughes from Synlait.

According to Dr Gibbs feeding a cow straw was required for good rumen function and to regulate the rumen's pH is "completely false" and "a total waste of time and money". Gibbs went on to say that the rumen's pH of grass based pastures was fine. Moving the pH around by adding straw did not increase a cow's production. Straw was indigestible, had a metabolic energy level between 6-8 and stayed in a cow's rumen for about 72 hours. When fed out daily, it would fill up the rumen at the expense of ryegrass.

"What you are doing is that you are diluting down your high metabolic energy (ME) diet for very low ME material for no benefit.

"Wherever straw has been put to the test it's always the same. There is no effect on the rumen pH, and production either stays identical or is reduced," Dr Gibbs said.

The exception was younger stock which needed straw for rumen development, Dr Roche added. There was no advantage in feeding high energy supplementary feed if there were enough pasture. The cows would simply substitute grass for the supplement with no added benefit in using the other source of feed.

Any new feed had to be managed correctly to avoid upsetting the rumen. It was not the amount of supplement that was important, but the rate at which it was applied, Dr Hughes said.

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