I might have mentioned before that I have a friend who is a vet nurse for one of the emergency out-of-hours services.

In the last 2 days he has been called out to a pregnant Newfoundland which collapsed in a park  - Hypocalcaemia, and last night had a pregnant St Bernard brought in with Hypercalcaemia.

In both cases the owners had been supplementing the bitches with calcium during the pregnancy.

It just shows what kind of people out there are breeding dogs nowadays - no knowledgeable breeder and certainly no vet will ever recommend calcium supplements during pregnancy due to exactly the risks of those happening.

unfortunately a 'little knowledge' is very dangerous, the owners have probably heard of the dangers of eclampsia and don't know that calcium supplements wont help in this and that too much calcium is very dangerous :-(  I guess they think that as pups need bones the mums need calcium :-(

> a pregnant Newfoundland which collapsed in a park  - Hypocalcaemia,

Well they couldn't have been suplementing much if the dog had Hypocalcaemia that is a lack of calcium and the solution is to give extra.
And I would be surprised if a dog collapsed from too much calcium. Hypercalcaemia

Actually, suplementing too much reduces the ability of the intestin to absorbe calcium and causes hypocalcemia.

I have not heard that before. do you have any scientific  references for this? thanks very much

Calcium metabolism http://en.wikipedia.org/wiki/Calcium_metabolism.

High levels off calcium supress PTH (parathyroid hormone), so the calcium isn't absorbed by the intestine, and the kidney doesn't transform calcitrol into vitamin D, and excretes the calcium.

The way it was explained to me by a vet over 20 years ago, is that in normal pregnancy where calcium supplements are not given, any calcium required by the growing puppies (or kittens) is taken from the mother's bones. This is entirely normal, and happens in human pregnancies as well. Therefore no supplementation is needed, and can lead to eclampsia if given.

What happens when calcium supplements are given, is that the female's body relies on the given calcium and doesn't utilise the body's calcium stores as normal. Either the given calcium isn't properly absorbed, OR at a certain point when the demands for calcium grow, it's not being taken from the appropriate source, and therefore eclampsia develops.

Usually this is when lactation starts and the female's body has a sudden high demand (as many of you will know). But supplementing during pregnancy can actually increase the risk of this happening, as the body doesn't 'learn' how to resource its own deposits at the right time. I also believe a certain gland is responsible for the regulation of calcium and it may be that it fails to do its proper job because of the supplementation.

What I hadn't heard of until now, was eclampsia during pregnancy which must be fairly rare - but clearly the owners of these Giant breeds had been supplementing, with disastrous results. Interestingly, the symptoms of both hypo and hyper calcaemia are the same = Eclampsia.

yes this is just how are understand it too temeraire :)

I have been led to believe also that calcium supplements can be responsible for secondary inertia too?