Farmers are being warned to manage minerals carefully at grazing as genetic improvement in grasses has increased variability of trace element availability.
Higher digestibility of grass often goes along with faster growth, but the pitfall is that this can also reduce the mineral status of the grass, according to Provimi ruminant nutritionist Philip Ingram.
“The amount of minerals and trace elements preset in the grass depends on the soil type, fertilisation and botanical composition of the pasture. The season, weather conditions and growth stage of grass plays an important role,” said Dr Ingram.
But while mineral levels may drop, Dr Ingram said fresh grass has higher levels of vitamins than winter forage. For example, grazed grass typically has twice as much vitamin E compared with grass silage and four times as much as maize silage, he said.
“Supplementation of this expensive vitamin may not be required at the same level as in winter rations, but to maintain antioxidant levels for optimum animal health, it may be more beneficial to consider a combination with other products.”
Provimi have carried out extensive trials that have found providing a perfect combination of antioxidants can increase immunity in cows. “Trials have shown that the antioxidant status of the blood – a good indicator of animal health – can actually be higher in animals given low levels of vitamin E with NuShield (a combination of antioxidants) than animals given a very high vitamin E.”