A recent provincial survey has revealed widespread mineral shortfalls in pasture forages across Manitoba. That's from Shawn Cabak, Livestock and Forage Specialist with the Manitoba Agricultural Services Corporation (MASC).
He notes the 2024 study, conducted by Manitoba Agriculture, examined a variety of grazing systems and forage types between late August and mid-September.
Copper and zinc levels were consistently low in forages across nearly all surveyed pastures.
"All the pastures were low in zinc except one," adds Cabak. "So, we can safely say that our forages on pasture are low in copper and zinc."
Aluminum levels were elevated in over half of the sampled pastures, which further inhibits copper absorption. Cabak advises producers to choose mineral supplements with higher levels of copper and zinc - ideally in chelated form for better uptake.
"Producers should look at the label of the mineral that they're using to ensure that it has higher levels of the micro minerals."
He also encourages more frequent mineral placement to boost intake, using covered tubs to protect from weather, and adding salt to encourage consumption - if salinity in the forage is not already high.
No soil solution for forage shortfalls
While soil supplementation can be used in annual crop systems - particularly on sandy soils prone to micronutrient depletion - Cabak says it is not a viable fix for perennial pasture deficiencies.
The most practical approach, he explains, is to implement a reliable mineral supplementation program tailored to herd needs.
"Calcium, phosphorus, all minerals are important for not only reproduction but production," continues Cabak. "We have to ensure that there is adequate supplementation in the diets."
Without it, he warns, producers may face lower conception rates and reduced livestock gains.
Protein and energy concerns late in season
While mineral balance is top of mind, Cabak says declining protein and energy levels also affect herd performance - especially as forage matures into late summer and early fall.
"Native pastures had the lowest overall quality for protein at nine per cent and energy at 57.6 per cent," he says.
In comparison, tame grasses and vegetative regrowth tested highest in nutritional value, while stockpiled mature forage ranked lowest. With many samples taken late in the season, some lactating cattle likely did not meet their energy requirements.
"That will better meet the livestock requirements."