Livestock farmers who suffered flooded fields last winter are being urged to get a full mineral analysis of grazing as the effects of the flooding could be to adversely affect mineral availability according to Adam Clay, Ruminant Manager with Trouw Nutrition GB.
“Grazed grass is at best a variable source of minerals with levels directly dependent on the mineral content of soils,” Mr Clay explains. “Some minerals will be in short supply giving rise to potential deficiencies while others can be present at high levels and can be antagonistic to other minerals. These risks increase where land has been waterlogged and where grass has been under water for any length of time.”
Mr Clay says that where land has been flooded the level of mineral leaching from the soil will be higher than usual resulting in poorer soil mineralisation. At the same time damage to the soil structure will reduce the ability of the roots to absorb nutrients from the soil, further depressing the levels available to livestock in grazing.
“Combined, these problems may lead to lower minerals levels at grazing which could results in a range of problems including suppressed immune system and lower fertility.”
Quoting results of grazing samples analysed at the company’s laboratory, Mr Clay says there has been a marked incidence of high levels of heavy metals which are antagonists to some minerals.
“Many samples analysed this spring have shown elevated levels of heavy metals such as iron and aluminium and trace minerals such as cobalt and molybdenum. This is almost certainly due to the soiling caused by flooding.”
He urges farmers to pay close attention to mineral nutrition at grazing and warns against just blanket increasing mineral supply, commenting that this can result in feeding minerals above the requirement level which can push up costs and potentially make issues with antagonism worse. He recommends having grazed grass analysed for mineral content, especially where fields were flooded or waterlogged for any length of time. Conserved forage taken from flooded areas should also be analysed for mineral levels to ensure a winter balance can be found.
“A mineral assay is the only way to understand the actual mineral levels in your grazing and the risks your cows are exposed to. You need to to understand the specific problem and then target supplementation from the most cost-effective solution.
“For example, if iron and molybdenum are locking up copper then it will be more important to feed the correct form of copper than necessarily just to increase the level fed. It will also be vital to reduce the levels of antagonists in supplementary mineral sources to alleviate the problem and to ensure legal maximum levels are not being exceeded,” he concludes.
