Selenium – SmartSel

Rumen-protected selenium supplement for dairy cows.

Selenium is one of those minerals you don’t notice until it’s missing. When selenium levels are low, cows can struggle to hold condition and cope through the higher-pressure parts of the season, especially around calving. SmartSel is a lipid-coated selenium (sodium selenite) designed to get past the rumen and release where it can be absorbed, so you get more consistent selenium intake. Selenium - SmartSel - Selenium supplement for cows

What this means for farmers

  • Fewer “why are they not bouncing back” moments after calving
  • Better support for immunity and reproduction
  • Better value from the selenium line in your mineral spend
  Talk to your local Agvance Consultant  

Why farmers should care about selenium

What does selenium do?

Selenium helps support:
  • Immune function
  • Fertility and cycling
  • Calving recovery
  • Calf health and vigour

What low selenium can look like on-farm

Low selenium can show up as:
  • More animal health issues, cows are not coping as well under pressure
  • More post-calving recovery problems, like retained membranes
  • Poorer performance and production, especially when other stressors are in play
  • Weak calves or white muscle disease in young stock when the deficiency is severe
If you’re seeing any of this, testing is the fastest way to confirm whether selenium is part of the story.

Why Selenium – SmartSel?

Standard sodium selenite can be tied up in the rumen and pass through. SmartSel’s lipid coating is designed to reduce those rumen losses so more selenium stays available for absorption later in the gut.

What’s inside?

Selenium (sodium selenite): A widely used selenium source in ruminant diets. Lipid coating (microencapsulation): A protective layer designed to help selenium get through the rumen and release where it can be absorbed.

SmartSel is ideal to use when

  • Herd blood or milk testing shows selenium is low, or not lifting
  • You want more certainty from the selenium part of the mineral plan
  • You’re heading into calving, early lactation, mating, or other high-demand periods
  • You need a selenium source that fits well in mineral mixes for your feeding system
Talk to your local Agvance Consultant

How to use

SmartSel is used as part of an Agvance mineral programme. Your Agvance Consultant will help set the right inclusion rate based on:
  • Your herd selenium status
  • Your feeding system
  • Other trace elements in the diet
  • Total selenium coming from all sources
Selenium can run low on some farms and high on others, depending on location and history. A quick herd test through your vet gives you a clear starting point. We can then set a plan that suits your farm. Call 0800 BALANCE, contact your local Agvance consultant, or log in to your Agvance account to order online. 

What the research shows

  • A study in dairy cows found that microencapsulated sodium selenite increased selenium transfer into milk compared with standard sodium selenite at the same inclusion rate, and performed similarly to selenium yeast for overall selenium availability. (DOI: 10.1017/S1751731113001547
  • A controlled lactation study found that coated sodium selenite increased blood selenium and glutathione peroxidase activity, and at higher inclusion rates improved milk yield, milk fat and milk protein compared with uncoated sodium selenite. (DOI: 10.1017/S1751731120000804
  • A meta-analysis of cattle studies found that selenium source and dose influenced the milk selenium response to supplementation, with stronger milk selenium transfer seen from some selenium forms than others. (DOI: 10.3168/jds.2008-1545
Limits

These studies test selenium supplementation strategies and protected or alternative selenium forms, not this specific Agvance product. They also do not directly test the product’s exact formulation in typical NZ dairy systems.

Study details and links

What was tested

Research on selenium supplementation in dairy cows, including microencapsulated sodium selenite, coated sodium selenite and broader evidence on how selenium source and dose affect selenium transfer into milk.

Milk selenium, blood or plasma selenium, glutathione peroxidase activity, antioxidant indicators, nutrient digestion and lactation performance.

  • Evidence supports protected or supplemented selenium approaches, not this branded product on its own. 
  • Results depend on selenium form, dose, background diet and the selenium status of the herd before supplementation.
DOSAGE METHODS

MIXER WAGON

SILO

FEEDOUT WAGON

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