Breathing difficulties can be caused by problems in the nose and throat, windpipe, lungs, chest cavity or heart. Severe pain, heatstroke and other conditions can also affect breathing. What matters at home is not trying to work out the exact diagnosis, but recognising when the effort of breathing itself is abnormal.
Warning signs are fast or markedly laboured breathing at rest, obvious use of the belly to breathe, an outstretched neck, being unable to lie comfortably, bluish or very pale gums, and collapse. Stress and physical effort can make the situation worse. Keep your dog as calm and cool as possible during the journey and avoid unnecessary handling.
Seek emergency veterinary care for obvious breathing difficulties. Call on the way if you can, so the clinic can prepare oxygen and rapid stabilisation. Do not wait at home to see whether an animal that is struggling to breathe gets better on its own.