[header] How to measure a dog's respiration rate [title] Take your dog's respiration rate when it is calm. [step] In order to determine your dog's respiration rate, make sure that it is calm. Dogs naturally increase their blood oxygen levels while at play or when anxious. 
This means that they breathe more in order to circulate more oxygen through their systems. Alternatively, if your dog has just finished playing and is hot, it will increase its breathing rate to exhale the heat in their bodies, in an effort to cool themselves down.