'Hairy buttercup, happy cow'

'Pasture weeds such as Californian thistle and hairy buttercup have a high mineral content of nutritional benefit to grazing animals, says Dr Kerry Harrington.

Dr Harrington, a weed expert in the University’s Institute of Natural Resources, conducted a study of the mineral content of weed species chicory, narrow-leaved plantain, dandelion, broad-leaved dock, hairy buttercup and Californian thistle. Some of which are grazed alongside perennial ryegrass and white clover pasture species on the University’s organic dairy farm.

Magnesium, manganese, copper, zinc, boron, cobalt and selenium were found in significantly higher levels in the weeds. The crude protein levels of these species, as well as in Yorkshire fog, were also higher than those in ryegrass.

“Advisers and farmers within the organic industry are often keen to increase the diversity of plant species within pastures, with mixtures called herbal leys that have a higher mineral content,” Dr Harrington says.

Dr Harrington says cows on the farm graze hairy buttercup, broad-leaved dock, dandelion and Yorkshire fog, and that Californian thistle will also be eaten if it is mown prior to grazing. For weeds often avoided by cows, Mr Harrington recommends block grazing over winter to ensure they are eaten.

He says organic farmers introduce alternative pasture species such as chicory and narrow-leaved plantain because of their high mineral content, but typically prefer to eliminate docks and dandelion. This difference prompted his closer look at the unwanted species.

He says the high mineral content of these weed species may be useful in keeping animals healthy on organic farms where only a limited range of health remedies are available should cows get sick.' --Massey News