High selenium levels

[ridernc]

I had my mare tested for her E/Se levels on 3/31. I did this before back in 2021 with a different vet at a different barn, but I never received the actual report; she just said her levels were normal/fine. These were the results from her test this year:

• Vitamin E - Result: 4.26, Reference Range: 2.0-4.0 ug/mL
  Notes: This value is more than adequate. Excess vitamin E is not toxic.

• Selenium - Result: 231, Reference Range: 120-180 ng/mL
  Notes: This value is above adequate. Animals with values in this range are receiving more selenium than necessary. There is no concern for toxicity, but intake or administration of selenium supplements should be reduced.

I originally did this test to confirm if she kept her Vitamin E levels up over winter because I did supplement Vitamin E from about November-February (UltraCruz Vitamin E Pellets, 1 scoop at 4000 IU/day). I was a little surprised by the selenium levels as I have never supplemented with an E/Se because I know the toxicity threshold is relatively low.

My mare is currently eating the following (per day, split into two feedings):

• 1lb Triple Crown 30% Balancer
• 1 scoop (80g) MadBarn Visceral+
• 2 scoops (100g) SmartSalt Pellets
• 2 scoops (30g) Uckele Poly Copper + Uckele Poly Zinc

I have not done a soil test, but according to USGS, the county she is boarded in has fairly low selenium concentrations (mean = 0.121 ppm). Our hay comes from New York state, but a recent hay analysis did not test for selenium.

When my current vet learned that I was not specifically supplementing E/Se, she recommended I switch to a different balancer with lower selenium levels. I respect my vet, but I do not get the sense that equine nutrition is her speciality, so I am looking for some other opinions. Are her selenium levels worrisome enough to justify switching balancer right now? My working theory is that she was eating higher selenium hay over the winter, which impacted her results. The horses haven’t been out on pasture in earnest until 1-2 weeks ago, and their hay consumption has dropped off sharply since.

Thank you for your thoughts!

[Obsidian_Fire]

Well, hmm. Some searching shows supplementation of Se 1-3 mg/day for most horses is acceptable and necessary. TC 30% contains between 3.4-4.4 ppm, how that converts to mg I do not know…

Last time I had a blood test in the 200 range my vet said, “whatever you’re doing, back off”.

I see JB is replying so I’ll let her take over!

[JB]

How much work is the horse in? That higher level isn’t necessarily a bad thing if they’re working hard enough, but that’s also not most horses.

Forage testing for Se isn’t reliable, so even if it was tested in the hay analysis, you can’t do anything with it, unfortunately

Where does the hay come from exactly? The S/SE counties of NY have high Se in the soil
Selenium in Counties of the Northeastern US (usgs.gov)

And option is to replace the TC Balancer with a forage balancer. Something like California Trace No Se would let you drop the separate cu/zn (or at least reduce it, I don’t know offhand how much is on your serving)

[JB]

@Obsidian_Fire

TC 30% contains between 3.4-4.4 ppm, how that converts to mg I do not know…

ppm is mg/kg, so to convert, divide by 2.2 to get mg/lb
4ppm is 1.8mg/lb.

[ridernc]

@JB

How much work is the horse in? That higher level isn’t necessarily a bad thing if they’re working hard enough, but that’s also not most horses.

4-5 days a week low-level dressage and occasional jumping. I wouldn’t consider her in heavy work.

@JB

Where does the hay come from exactly?

I can ask.

@JB

And option is to replace the TC Balancer with a forage balancer. Something like California Trace No Se would let you drop the separate cu/zn (or at least reduce it, I don’t know offhand how much is on your serving)

One of the reasons I am hesitant to switch is because she is an incredibly picky eater, and this combination has been working after much trial and error. (There’s a reason I’m paying a premium for pelleted salt!) I did suggest this to my vet, but I’m not sure she knew what I was talking about.

I certainly want to do what’s best for her, and if I have to take her off the balancer, I will. Honestly, she doesn’t need the calories. It’s going to be a bit of a change to maneuver (her barn only feeds senior-type feeds, so it was already a negotiation to get her on just balancer), so I want to make sure this isn’t jumping the gun.

ETA: Are there any no-Se pelleted options? She will not eat anything powdered. The pelleted CA Trace seems to include Se.

[ProfAmEq]

I used Madbarn Omneity pellets for a while and it has no Se. I actually prefer it to the TC balancer. You can mix it with a pound of just TC Senior for palatability or cals if needed.

[JB]

081221_KIS TRACE PELLETS NO SELENIUM (thornebottomfarm.com)

@ProfAmEq

I used Madbarn Omneity pellets for a while and it has no Se.

It does have Se, it’s just not listed in the GA (which is ) It has Sel-Plex in the ingredient list which is selenium yeast .

[ProfAmEq]

Oh man, that’s annoying. Wonder if it’s measurable—I really like Madbarn and that is weird they wouldn’t list it!!

ETA: OP may want to email Madbarn about it and ask if they have more information. They’ve always been extremely responsive when I’ve had questions.

[JB]

@ProfAmEq

Wonder if it’s measurable—I really like Madbarn and that is weird they wouldn’t list it!!

they should absolutely be able to tell you how much is in it. I don’t know Canadian rules but US requirements are that Se be listed in the GA.

I also realized they add lysine and methionine to it by don’t list them in the GA either

[Simkie]

When I had my horses in Colorado, Se tests like this (or higher) weren’t unusual. CO is really selenium rich, to the point of toxicity in some mountain pastures. This type of value was never a concern, and toxicity is much higher.

It might be interesting to retest in several months to see if it’s stable, dropping or rising.