Fading puppy is characterized by a typically smaller puppy who, while once thriving, becomes lethargic and 'fades' at some point - usually in the first two or three weeks of life. This can occur in large or small litters and in large breed or small breed animals. I am most familiar with large breeds and I do know that hypo and hyper glycemia is a real problem in toy breeds so please take my advice as a general guideline only. There is no substitute for Veterinary advice and that should be sought first and foremost. Its also only fair to point out that the prospects for a fading puppy are not good - when an entire litter is fading; you will likely not get a good outcome.
I have, however, saved a fading puppy and directed someone on how to save and I never give up so I pray this helps anyone in need.
Items you will need: 3 or 5 ml oral syringe, Karo syrup (clear is better), sterile (boiled or bottled) water, milk replacer for canine puppies.
First the background: puppy that was nursing that no longer nurses well, lethargy is your biggest sign, Dam may move the puppy away further complicating the issue with heat loss. In some cases a puppy may fade because of sickness or congenital defect - these will be almost impossible to save. However, a great many cases are of unknown cause and these are the babies you can save.
*Caution; Never, ever feed a baby whose rectal temperature falls below 95 degrees F. You must warm the baby first. A hot water bottle with a towel over it, heat lamp, or heat pad with a towel will do fine. I personally like Kangaroo holding (placing baby on my skin - usually in my cleavage is the best way to get heat passed on to body surface).
While you are making the baby warmer, mix a 50/50 solution of sterile water and karo. This must be warmed to 'wrist' temperature. Draw into oral syringe and dropper this on baby's tongue. This is a trouble shooting science so you are going to do a lot of observing. I'd go with about 5 drops and wait 5 minutes. If this seems to get energy into the baby, I'd switch the meal over to milk replacer. You will need to look up the amount of a 'meal' dependent upon the weight of your animal/ volume of feed per day/ number of meals per day (I'll put these guidelines in the milk replacer document). From this point I'd always remove the larger puppies and try for an assisted nursing on the Dam first. If lethargy is present, go with the 50/50 glucose solution as outlined above.
If you are using the 50/50 glucose and can't get any energy I would give the 5 drops and re-administer that every thirty minutes. Try this for four hours and 'kangaroo hold' in between. I don't know the scientific proof behind the kangaroo hold, but it just felt like my heat and heartbeat were an essential part of the cure. After 4 hours of glucose therapy, you have exhausted really your efforts at troubleshooting blood sugar issues and must then try for milk replacer. I would stay in a holding pattern at that point of 5 drops glucose followed by immediate milk replacer. Do this every two hours. I will tell you that an experienced Dam's reaction to the puppy will tell you a lot. If she takes and cares for the baby well, your prognosis is good. Is she continues to segregate or remove the puppy, it is because she knows something we don't. A Dam can tell the rectal temperature of a pup by licking it (amazing!) and they determine health this way.
***Problems - If baby just can't get the energy together to suckle, after the glucose therapy I'd gently rub fur AGAINST the grain. This is an irritant and will get a limited amount of 'awakeness' so you can get suckling. A baby with diarrhea is in severe danger!! Go to pedialyte without flavor in this case. Glucose will only exacerbate diarrhea. In this scenario I would prefer a powdered milk replacer that I re-constituted with pedialyte. A Vet can administer Sub-cutaneous fluids in an extreme situation. Dehydration is hallmarked by skin 'tenting' on the neck. You pinch the excess skin and it retains that tent shape.
Your ultimate goal is to wean off the glucose in favor of milk replacer, ultimately in favor of the Dam's milk. I have no problem pulling a large baby off a teat and plugging in a small baby. A faded puppy will be in danger of relapse for the next week or until they attain the age of 4 or 5 weeks old. Prognosis is for a normal life if the cause was not a congenital defect.
Never give up!! I thought for sure I'd lose my baby as she was only 7 oz at birth. She is a spunky, happy adolescent now!