Death in puppies may involve one or two puppies, or the complete litter. Generally speaking, the nearer the puppy is to the exit, the greater is its chance of survival, if there is nothing to retard delivery. Nevertheless, this first puppy to be born is the one least likely to survive if it is badly out of position, and especially if surgical interference is needed to effect delivery. The greatest risk, however, to the first-born results from undue panic on the part of the attendant.
If, instead of making frantic efforts at midnight to effect the delivery of a living, normal puppy before the cervix, vagina, and uterus have reached the state of readiness, the owner were to go to bed and sleep soundly until morning, he or she would probably find on awakening that the first puppy presented, as well as others, would be comfortably sucking.
In any case, a few hours’ delay in the case of the untouched and uninfected vagina will not impede the efforts of the veterinary surgeon, if his services are finally required.
The exception is when the puppy is dead, swollen and partly decomposed a very unlikely state of affair or when it is lying in such a position that it entirely precludes the possibility of normal birth. Even then, waiting a short while entails very little extra risk, provided no outside infection has been introduced by unclean fingers.
The retention of normal puppies for a few hours, within a healthy uterus, does little harm, since they are receiving oxygen and nourishment through the placenta, and have not yet inflated their lungs. Undue hurry is far more likely to be dangerous.
Now let us consider why one or more puppies should arrive dead among an otherwise strong and healthy litter. Firstly, take into consideration the size of the dead puppy. Is it a large, well-developed specimen, as usually is the case, or is it a small one, thin, shrivelled, and almost mummified?
During the early days of pregnancy it is usual for more eggs to be fertilised and implanted in the lining of the uterus preparatory to development and growth than finally survive. The defunct embryos undergo a process of resorption. As there may be insufficient time for this to be completed, the puppy is eventually delivered as a small specimen, not actually decomposed but apt to give this impression on account of its partial mummification. Sometimes it will be embedded in, or surrounded in its membranes.
When several puppies, or even the whole litter, are involved in this way, the underlying cause may have been either lack of vitamin A in the diet of the bitch at the early critical stage of embryonic development; or, alternatively, inability on the part of the bitch to make use of the vitamin A available. One reason for this may be the administration of wheat-germ oil, or vitamin E (the so-called ‘fertility hormone’) in excessive dosage. Too much vitamin E is capable of rendering the bitch unable to absorb the essential vitamin A. On the other hand, the lack of development may have been due to infection, possibly by E. coli.
There may be a variety of other causes of the death of a large, well-developed puppy prior to birth. The matter of sex may play a part since a large male has far less chance of survival during a somewhat prolonged parturition (in which uterine inertia may be involved) than a smaller female.
The other common cause is obstruction to the circulation of blood, involving an insufficient circulation of oxygen within the puppy’s bloodstream. This often results from entanglement of the umbilical cord (carrying the blood vessels) around some part of the puppy’s own body, or by its becoming imprisoned by the limbs of another puppy. Sometimes a rotation of the body of a puppy carries the cord, which is fairly long, around the abdomen, thereby diminishing or cutting off the circulation.
Another cause is that, frequently, puppies arrive in `posterior presentation’, in other words, ‘tail first’. This may apply to alternate puppies but sometimes all, or almost all, arrive in this way.
The passage of the puppy is impeded, and the bitch makes strenuous ‘forcing’ efforts to keep it moving. Fluids are then squeezed down the nostrils and open mouth of the puppy and pass into the lungs. The result is that when the puppy eventually makes an effort to breathe it fails because the lungs are full of fluid; or in other words, the puppy is drowned.
A complete litter ‘dead at birth’, from a bitch that has been watched and not neglected, and has delivered her puppies without undue effort, is often the result of infection, frequently by a virus (distemper or hepatitis possibly) or sometimes by leptospira (rodent infection?) and even by common bacteria such as E. coli, a normal inhabitant of the intestine which, in certain circumstances, may become highly virulent.
The infection may result in death of the puppies and premature birth, or they may be retained until full term and delivered dead.