Is it possible to overdose on copper?

[Casey76]

Both of my horses have faded awfully this summer, despite being on Pro Hoof (175mg chelated copper) where as last year they were both deep black.

They are in a different field to last year, but only by about 100 yards. They hay we have is of variable quality, and changes on a weekly basis (We have communal hay, and share 1 round bale between 14, which means we can get a new bale every three-4 days).

I know that this area is desparately low in selenium, but apart from that I'm not sure about other mineral deficiencies.

 

[Nudibranch]

From memory I think copper in large doses is toxic so you need to be careful, obviously they need trace amounts but not too much.

 

[Tnavas]

YES most definitely. Be careful of over doing it. Have a blood test done for Sellenium. Mine has a horrible coat at the moment and I've arranged with vet to take a sample.

 

[Fides]

Copper is a heavy metal so yes.

 

[amandap]

The only way to know the mineral profile is test grazing and hay they are eating. Fields next door to each other can have very different profiles and even within the same field, this is why samples are taken from various spots in a field.
Yes all minerals can be overdosed but selenium is especially dangerous in excess.

The test results need interpreting and a feed plan formulating, you cannot extrapolate directly from the results.

 

[Erin]

http://www.understanding-horse-nutrition.com/copper.html

"It appears that horses are fairly tolerant of high Cu concentrations. When horses were given large amounts of Cu orally, no adverse reactions were seen.

Thus, the maximum tolerable concentration for horses has been set at 250 mg/kg of ration. This level is way above the recommended intake level of 10 mg/kg dry matter"

 

[Brightbay]

Both of my horses have faded awfully this summer, despite being on Pro Hoof (175mg chelated copper) where as last year they were both deep black.

They are in a different field to last year, but only by about 100 yards. They hay we have is of variable quality, and changes on a weekly basis (We have communal hay, and share 1 round bale between 14, which means we can get a new bale every three-4 days).

I know that this area is desparately low in selenium, but apart from that I'm not sure about other mineral deficiencies.

I feed the Forageplus balancer - which has 400mg per 100g - the ProHoof wasn't enough for us. It's not the amount of copper per se, it's how much of the uptake is blocked by high levels of iron and manganese in the grazing. So in e.g. Field (a) with low levels of iron and manganese, the horse would be able to use 70% of the copper they take in. In Field (b) with high levels of iron, the horse will only be able to use 30% of the copper they take in. That's why they call it mineral balancing - you balance the copper/zinc against the iron/manganese.

Obviously, like all heavy metals, there is a toxic amount, but IME horses won't eat anything like that amount - it's hard enough to get them to eat a small amount of copper in a single feed!

 

[Casey76]

Selenium deficiency is a big problem in this area. My youngster had to have two selenium injections and was on a selenium supplement for almost 6 months.

There is absolutely no point in getting the hay tested, it is too variable. One day we had a lovely meadow-hay like bale with very fine grasses, the three days later we had a wrapped bale that was mainly docks, another two days later we were back to dry hay, but it was long and very coarse.

I guess it's time to get an MOT and bloods done again...

 

[amandap]

There is absolutely no point in getting the hay tested, it is too variable. One day we had a lovely meadow-hay like bale with very fine grasses, the three days later we had a wrapped bale that was mainly docks, another two days later we were back to dry hay, but it was long and very coarse.

This is why I feed a good (high spec) balancer but if mine were grazing a lot I would test my grass, especially if I was worried about excesses or had on going problems. I was trying to make the point that the field change may be part of the problem. It sounds like deficiencies may be more of your problem tbh so I assume your worry is around supplementing extra copper. In your situation I would upgrade to Forage plus if bloods don't show any excesses but I understand bloods aren't a 100% reliable test for mineral deficiency.

 

[Exploding Chestnuts]

OP has mentioned LOW selenium, but her Q is asking if he is getting too much Cu, which is not likely.
Before getting bloods I would make sure that you will get the results you want from the test., personally I would be surprised if he is the only one affected AND if he was OK last year. Are the hooves normal? Is the mane normal?
I would find a broad base mineral but one which has a higher Selenium input per day, give that a try for 6 weeks. Try phoning Equimins as they have a few specialised mineral mixes.
Also micronised linseed helps coat and skin, as I discovered when my boy stayed dark after supplementing all year round.

 

[Dizzle]

Surely the coat fading is to do with the lovely sun we have had this year?

Both mine and a friend's pony have wonderful highlights at the moment, first year that they've had them!

 

[Casey76]

OP has mentioned LOW selenium, but her Q is asking if he is getting too much Cu, which is not likely.
Before getting bloods I would make sure that you will get the results you want from the test., personally I would be surprised if he is the only one affected AND if he was OK last year. Are the hooves normal? Is the mane normal?
I would find a broad base mineral but one which has a higher Selenium input per day, give that a try for 6 weeks. Try phoning Equimins as they have a few specialised mineral mixes.
Also micronised linseed helps coat and skin, as I discovered when my boy stayed dark after supplementing all year round.

Sorry if my question was unclear. I'm actually wondering if I can top up the amount of copper he is already getting.

There is one other "black" horse on the yard, we would call her a "bai-noir" though, she fades awfully during the summer and appears dark bay.

My two are on Pro-Hoof and linseed all year round (starting in September time-ish), and last year they were both deep black.

Surely the coat fading is to do with the lovely sun we have had this year?

Both mine and a friend's pony have wonderful highlights at the moment, first year that they've had them!

I'm not in the UK, and this year the summer has been very hit and miss. Only a few days over 30°C, lots of rainy days breaking up the sunny ones. Although they have fly rugs, they have only only needed them for only a few weeks, rather than constantly.

Apart from their foal coat, my horses breed should be deep black all year round.

 

[Exploding Chestnuts]

I would be very wary of feeding a single mineral supplement without being sure of your reasoning as the minerals are balanced with each other. Copper deficiency usually shows up as a reddish tinge in a black mane.