Use a digital rectal thermometer made for pets
Lubricate the tip with petroleum jelly or water-based lubricant
Have someone gently hold the dog still if needed
Lift the tail and insert the thermometer about 1 inch into the rectum for small dogs, about 2 inches for larger dogs
Hold the thermometer in place until it beeps or gives a reading
Remove it and read the temperature
Clean the thermometer with soap and water or disinfectant after use
Normal dog temperature is about 101 to 102.5°F
Contact a veterinarian if the temperature is below 99°F or above 103°F