Message Number: FHL14203 | New FHL Archives Search
From: Sukie Crandall
Date: 2011-10-24 16:40:31 UTC
Subject: Re: [ferrethealth] Calcium Levels on Blood Work

Hypercalcaemia/hypercalcemia IF she is at the level of that poses the same risks to ferrets as it does to dogs and, as with dogs, one of the causes which can happen is too much vitamin D. This post will just address the dietary possible cause.

It is too bad that the MSU article was not coming up last night because it contains information that D can come from some sources the food maker discussed (Blue Buffalo) did not count in its calculations. I'll see if it is coming up now. The links are in
Nope. I do NOT know if it will be available later.

Humans need a lot more D than ferrets do. We get it from foods and from exposure to the sun.

The funny thing is that I just sent a post late last night to the Ferret Mailing List which is partly on that so I will just copy my full FML post here to help you:

There's been a lot about that so i will trust people to actually look up most of the reputable resources out there, but the confusion sadly remains.

Animals who are descended from others that regularly got livers are adapted to deal with decent levels of A which is in high amounts in liver. Can they get too much? Sure, but it takes a lot to do that with them, unlike with humans.

On the other hand, animals which had ancestors with mainly crepuscular activity (dawn and dusk) or nocturnal activity, and especially those whose ancestors were also burrow dwelling have a harder time with vitamin D, unlike humans whose ancestors had a lot of sun exposure.

So, ferrets are kind of the opposite of us for those two vitamins and those differences confuse some people.

First D:

What happens when a type of animal, like ferrets and dogs, which are not geared to getting much D do get too much D? They develop hypercalcemia with calcium deposits in organs, especially in the kidneys and heart. In fact, there were multiple discussions about that recently. Obviously, they do need some, but not in high levels since they get overdosed quite easily.

Therefore it pays to make sure the ferret is not eating more vitamin D than is healthy for her.

There are a number of reputable refs on that. I don't have time to find many but you can start with things like this and those who were at the symposium in PA will recall Dr. Tom Willard mentioning the [D] concern for ferrets, too, in discussions:

> J Small Anim Pract. 2005 Jul;46(7):334-8.
> Hypercalcaemia in two dogs caused by excessive dietary supplementation of vitamin
> D.
> Mellanby RJ, Mee AP, Berry JL, Herrtage ME.
> Queen's Veterinary School Hospital, University of Cambridge, Madingley Road,
> Cambridge CB3 0ES.
> A three-year-old Border collie was presented with a two-week history of lethargy,
> stiff gait, polydipsia and polyuria. Biochemical analysis revealed
> hypercalcaemia. Serum concentrations of 25-hydroxyvitamin D (25[OH]D) and
> 1,25-dihydroxyvitamin D (1,25[OH]2D) were markedly elevated and parathyroid
> hormone was undetectable. Subsequent analysis of the dog's diet revealed that the
> food contained excessive amounts of vitamin D. The hypercalcaemia resolved
> following treatment with bisphosphonates and dietary change. Hypervitaminosis D
> was diagnosed in a second unrelated dog, which had been fed the same brand of dog
> food as case 1. The dog was also hypercalcaemic and had markedly elevated serum
> concentrations of 25(OH)D and 1,25(OH)2D. Hypervitaminosis D in dogs has been
> reported to occur secondarily to ingestion of either rodenticides containing
> cholecalciferol or antipsoriatic ointments that contain vitamin D analogues.
> Hypervitaminosis D has also been reported following the treatment of
> hypoparathyroidism. To the authors' knowledge, this is the first report of
> hypervitaminosis D in dogs following the accidental over supplementation of a
> commercial diet with vitamin D. While the benefits of adequate dietary vitamin D
> are well established in dogs, the potential deleterious effects of over
> supplementation of vitamin D should also be acknowledged.

See, too:

The MSU Veterinary School periodic magazine which went into that in detail is currently not coming up. Links were given when it first appeared, and perhaps those who missed it then will be lucky enough to have it reappear in the future.

Okay, now moving from D to A:

What happens when a type of animal, like ferrets, who are geared to get a good amount of A don't get enough A? Well, among other things they appear to have decreased resistance to some serious diseased like canine distemper. There are also increased problems with diarrhea, cataracts, behavioral alternation, and more.

> 1. J Nutr. 2007 Aug;137(8):1916-22.
> Disease manifestations of canine distemper virus infection in ferrets are
> modulated by vitamin A status.
> Rodeheffer C, von Messling V, Milot S, Lepine F, Manges AR, Ward BJ.
> McGill University Health Centre Research Institute, Faculty of Medicine, Division
> of Infectious Diseases, Montreal General Hospital, Montreal, QC, Canada.
> The measles virus (MV) causes half a million childhood deaths annually. Vitamin A
> supplements significantly reduce measles-associated mortality and morbidity. The
> mechanisms whereby vitamin A acts against MV are not understood and currently
> there is no satisfactory small animal model for MV infection. We report on the
> development of a ferret model to study antiviral activity of vitamin A against
> canine distemper virus (CDV). CDV is closely related to MV at the molecular level
> and distemper in ferrets mimics measles in humans. We infected vitamin A-replete
> (control) and vitamin A-depleted ferrets with CDV and assessed the ability of
> high-dose vitamin A supplements to influence CDV disease. In control ferrets, CDV
> infection caused fever, rash, conjunctivitis, cough, coryza, and diarrhea. In
> contrast, control ferrets that were given 30 mg of vitamin A did not develop
> typical distemper after infection and exhibited only a mild rash. The supplement
> did not negatively affect ferret health and resulted in a 100% increase in serum
> and liver vitamin A concentrations. We also found that profound vitamin A
> deficiency is inducible in ferrets and can be rapidly reversed upon high-dose
> vitamin A supplementation. Vitamin A deficiency caused anorexia, diarrhea,
> cataracts, behavioral abnormalities, and ultimately death, with or without CDV
> infection. All ferrets that received vitamin A supplements, however, recovered
> uneventfully from CDV infection. These results replicate many aspects of the
> observations of vitamin A therapy in humans with measles and suggest that CDV
> infection in ferrets is an appropriate model for the study of the antiviral
> mechanism of vitamin A.

Full article for free:

Fish oil is a good source of omega 3 fatty acids which are useful for kidney health in ferrets, but cod liver oil -- as opposed to "fish oil" which is from entire fish instead of just livers -- is very high in A, so unless a ferret is fighting canine distemper or in a risk situation for CDV that is best given somewhat sparingly just to be safest, while remembering that ferrets do cope with higher A levels better than people do, and appear to need higher A levels proportionate to size than we do.

BTW, unlike humans, ferrets and a number of other members of Carnivora have difficulty converting some vegetable precursors of vitamin A into vitamin A.

On Oct 24, 2011, at 11:18 AM, pigleeownee wrote:

> Hello. I had routine full blood work up done on my healthy 6 year old ferret Daisy. The vet said her calcium was high so she wanted to retest her in a month.
> The normal range states: 8-10.0
> Daisy was: 11.4
> I researched and found this can show problem with cell activity, muscle, and possibly lymphoma issues.
> Does anyone know what else could cause this increase and if it is something I should be worried about at this point?
> thank you,
> Diane

Sukie (not a vet)

Recommended ferret health links:
all ferret topics:

"All hail the procrastinators for they shall rule the world tomorrow."
(2010, Steve Crandall)


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