GLOBAL - Rumen acidosis could be reduced by feeding nettles, a University of Reading study has concluded, although researchers aren’t sure why.
Test tube studies have found stinging nettle (Urtica dioica) haylage increased the pH of a rumen fluid by 30 per cent for a period of a week in place of ryegrass silage (Lolium perenne).
Feed intake reduced in the six lactating Holstein-Friesian cows fed the ration but no reduction in milk yield was seen and rumination time dropped as nettle inclusion increased.
The discovery, researchers said, could be of potential use for systems feeding grain heavy diets but two possible reasons could be behind the nettle's effect on maintaining rumen pH.
“It is not certain if the effects observed were due to differences in the chemical composition of grass versus nettles or specific bioactive components of stinging nettles,” the report said.
Diets containing more nettles reduced the time rumen pH was at 5.5, the critical level for rumen acidosis.
This trial builds on a 2005 study, also from the University of Reading, which found that stinging nettles could “maintain a significantly elevated” pH in a test tube medium. The same was true for lettuce leaves.
Both papers form a body of research looking at the function of 500 plant extracts as part of European Commission initiative Rumen-Up, a research programme started in 2005 to find new plants to make ruminant production more sustainable.
The project aims to reduce pollution - methane and nitrogen - and improve animal welfare by dealing with bloat and acidosis, while exploring alternatives to antibiotic growth promotion.