Golden Retriever, 9 years old, healthy all its life, now when lying down the lower belly bulges and looks large, but returns to normal when standing; not pregnant. Could it be ascites?

Ascites can be preliminarily judged by palpation and confirmed with X-rays and abdominal ultrasound; fluid gives a clear wave and a soft, deformable belly. In contrast, a mass or organ enlargement feels firm with no wave and may have a hard lump. Besides ascites, a Golden’s swollen belly can come from tumors, which are common in the breed, so check enlarged lymph nodes and do a thorough exam.

Pyometra can enlarge the belly, especially in unspayed females over 5-6 years, needing surgical removal. Liver and kidney enlargement from organ disease also causes abdominal swelling, so veterinary evaluation is important.