With mating well underway down South and early pregnancies progressing in the North, supporting your in-calf cows with the right balance of minerals can help maintain healthy pregnancies, grow strong calves, and set your herd up for a productive season.
“Subclinical deficiencies in key minerals like selenium, iodine, copper and zinc can lead to embryonic and foetal losses,” says SealesWinslow Product Technical Support and Veterinarian Tiffany Menzies.
“That means all the hard work to get cows cycling and conceived could be wasted, leading to cows showing up empty at scanning.
“With a good payout on the horizon, nailing your herd’s reproductive performance could make a big difference to your bottom line.”
Understanding sub-clinical deficiencies
While it’s easy to spot animals with obvious mineral deficiencies - such as poor growth, low fertility, or visible health issues - sub-clinical deficiencies often fly under the radar. These hidden shortfalls can quietly reduce immunity, fertility, and productivity without any obvious symptoms, costing farmers in lost performance.
“By the time clinical issues appear, production losses may already be significant. Testing and early intervention can make a big difference,” says Tiffany.
Regional differences in mineral deficiencies add another layer of complexity.
“These variations mean farmers need a tailored mineral supplementation plan to meet their herd’s specific needs depending on where they farm,” says Tiffany. “Regular testing of animals, pasture and even soil, are crucial to identify gaps and effectively address them.”
Key minerals for healthy pregnancies
Pregnancy and lactation put a lot of stress on a cow’s body, and minerals are critical for keeping things running smoothly.
This article offers just a quick snapshot of some essential trace minerals and their many roles in supporting health and peak productivity. Here are five key minerals to watch:
Cobalt: Essential for the production of Vitamin B12 in the rumen, supporting energy metabolism, fibre digestion, immune function, fertility and milk production.
Copper: Needed for pregnancy, milk production, fertility, immunity and animal health. Consider the presence of antagonists such as sulphur, iron, and molybdenum, which can interfere with copper absorption and utilisation.
Iodine: Vital for energy and protein metabolism. Low intakes risk embryo and foetal health, reduced milk production and reproduction.
Zinc: Goes beyond merely facial eczema control. It is essential for maintaining healthy embryos and reproductive success, integrity of hooves, immunity, and milk production.
Selenium: Necessary for reproduction, prevention of embryonic losses, immune function and disease resistance, and milk production. Selenium deficiency is widespread in New Zealand, making supplementation critical in affected areas.
With trace minerals needed in micro amounts, they need to be balanced carefully with other minerals. Always consider the presence of antagonists, also in water, such as iron which can block absorption of key nutrients like selenium and zinc, making supplementation even more important.
Keeping it sustainable
While it’s important to address deficiencies, supplementation needs to be informed and strategic. Over-supplementing can waste resources, affect profitability and even adversely impact the environment.
“Farmers can maximise efficiency by understanding that trace mineral assessment and supplementation is multifaceted,” says Tiffany. “It’s important to look at the whole picture. Assess your herd’s mineral needs in the context of the animals, their overall diet including pasture and water, soil mineral test results, and the types and sources of trace mineral supplements provided.”
What you can do
Looking after your cows’ mineral needs doesn’t have to be complicated. Here’s how to get started:
Test and monitor: Regularly monitor and sample animals (eg. blood samples and liver biopsies – including cull cows), pasture and soil tests to spot deficiencies early.
Supplement strategically: Bulk feed or inline water systems are easy ways to deliver what your cows need.
Avoid overdoing it: Trace mineral levels vary between herd individuals, seasonally and regionally. However, beware as trace minerals given in excess can result in toxicities. Therefore, always check supplementation responses and adjust as required.
Plan for summer: Pasture quality declines in summer and can impact on trace mineral availability.
