Hypocalcemia (low blood calcium)
brought on by the following:
Poor Nutrition - "Home brewed" diets
usually are at fault. The owner innocently may be adding too much unbalanced
meat to the bitch's diet, thinking the extra protein is beneficial. What's really
happening is the calcium to phosphorus ratio is out of balance because the
amount of useful calcium in the food is actually reduced! The ideal contains a
ratio of calcium to phosphorus of 1.2 to 1. (Many organ meats such as liver
have a ratio of calcium to phosphorus of 1 to 15!! Liver is great for dogs but
if it comprises a large part of the diet, the calcium/phosphorus ratio of the
diet will be improper.)
Eclampsia, or milk fever, is an
acute, life-threatening condition which attacks a brood bitch about 3 to 4
weeks after whelping puppies. It is more common in the small breeds of dogs
that have had large litters.
People often give their brood-bitch heavy calcium
supplements during her pregnancy, however this does not prevent eclampsia, and
can actually cause it to reoccur during future pregnancies.
Over-supplementation of calcium
during pregnancy may increase the risk of eclampsia. There is a complex way the
body maintains the proper amount of calcium in the blood. The body is
constantly adding calcium to bones and then removing it, as needed. This is
regulated by a hormone produced by the parathyroid gland, called parathyroid
hormone. If a dog receives increased amounts of calcium during pregnancy, her
body's production of parathyroid hormone greatly decreases. When the dog
suddenly needs large amounts of calcium for milk production, the system is not
ready to start removing it from the bone. This is because it takes some time
for the parathyroid gland to start producing the hormone again. Because of the
lack in parathyroid hormone, the blood calcium level suddenly drops, and
produces the signs of eclampsia.
So, adequate amounts of calcium need to be given
during pregnancy, but not enough to slow down the production of parathyroid
hormone. This means calcium supplements are generally not recommended. Also, it
is important for the calcium and phosphorus in the diet to be at the correct
ratio of 1:1 (i.e.; 1 part calcium to 1 part phosphorus). Vitamin D must also
be present in adequate amounts.
Once a dog has had milk fever, there is an excellent
chance that she will also have it with future litters if preventive steps are
not taken. Be sure to work closely with your veterinarian if your dog has had
eclampsia in the past and is pregnant again.
In conclusion, it is of great importance for owners
of pregnant or nursing dogs to be able to recognize the signs of eclampsia. If
you feel your female dog is showing these signs, remove the pups to prevent
further nursing and seek veterinary assistance at once.
Inappropriate calcium supplementation can predispose a bitch to develop eclampsia.