My 10-year-old German Shepherd has labored breathing at night. Why?

Hello and thank you for reaching out to Petco Pet Education Center, formerly Petcoach. I'm sorry to hear that Zeta has been having labored breathing. Difficulty breathing can be a sign of primary respiratory disease, such as pneumonia, fluid in the lungs or chest, or even lung cancer. Heart disease can also cause fluid to build up in the lungs, which can lead to difficulty breathing, especially at night. I recommend monitoring her breathing rate and effort. If she is breathing more than 40 breaths per minute, or using her abdomen to help her breathe, I recommend having her evaluated by a veterinarian. I hope this is helpful!