A dog's normal rectal temperature is 100.5 to 102.5 degrees Fahrenheit. Ear temperature is slightly different: between 100.0 degrees and 103.0 degrees.
Illness is the top cause of abnormal body temperature in dogs. You usually see a rise in temperature, but there are some cases where you can see a lower than normal body temperature too.
Could she be pregnant? Pregnant dogs, just before delivery, experience a drop in body temperature. In fact, this is how breeders can tell when a litter is imminent.
If she feels cool to the touch, especially on her extremities, it could be a case of poor circulation, which can result from heart problems, disorders with the blood, and blood clots, among others.
There's also certain illnesses that cause low body temperature. Viruses, some not too serious and others more serious, like Parvo, can cause this. So that's an avenue to explore further with your vet.
Problems in the brain, like a tumor or trauma, can also cause abnormal body temperature. So that's something that your vet may want to investigate further, especially if there's no obvious cause.
Is she shivering? Is this why you think she's cold? If so, it may not be due to cold. It could be due to something else, like low blood sugar, which can result from not eating or from various metabolic disorders. Pain and nervousness can also cause shivering.
To better determine what's going on here, I would check a few other markers that can better inform you on how urgent of a situation this is:
Checking the gums is an indicator of your dog's circulation. If there's internal bleeding, anemia, a disruption of normal blood flow, or serious illness, the gums will turn very pale, almost white in appearance. This means that the blood is not properly receiving oxygen or there's a loss of blood or red blood cells.
Normal gums will be bright pink to a pale pink. Abnormal gums are white with greyish, blue, or yellow.
Here is a link to a photo of normal gums:
Here is a link to a couple of photos of pale gums:
I should note that I've seen perfectly healthy dogs with gums that are slightly paler than those pictured in the "normal gums" picture, but there's always a distinct pink tone.
For more information on checking your dog's gums, visit:
The normal heart rate varies depending on the size and age of the dog. A puppy has a heart rate of about 180 beats per minute. And adult dog will have a rate between 60-160 beats per minute. Small toy breeds can have normal heart rates of 180 beats per minute. The rule is the younger the dog, the faster the heart rate (for puppies). And the smaller the dog, the faster the heart rate.
Normal pulse is between 60 and 120.
Also, you can check capillary refill time. If you apply firm pressure to the gums, the area should turn pale and then quickly return back to normal (you can try this on your own skin to see what I mean). If there's no difference, or if your dog's gums take a long time to return back to normal, there could be a problem. The gums should return to normal in no less than one second and no more than two 1/2 seconds.
You can also try her on some bland "people food" such as plain white rice and boiled hamburger if she gets hesitant to eat before you get to the vet. She may find this more appealing than her normal food, as an ill dog can be finicky.
If she stops eating due to illness, you can give a couple of spoonfuls of pancake syrup every six hours to prevent hypoglycemia (low blood sugar), which will just make her feel worse.
Here's a good site on temperature and how to take it:
I hope your dog is well! Don't hesitate to let me know if you have any additional questions!