Swollen lymph nodes in horses can be caused by a wide variety of things, including:
* Infections: Bacterial, viral, fungal, or parasitic infections can all cause lymph node swelling.
* Inflammation: Non-infectious conditions, like injuries or allergies, can also trigger lymph node swelling.
* Cancer: In rare cases, swollen lymph nodes can be a sign of cancer.
It's important to consult a veterinarian immediately if you notice swollen lymph nodes in your horse. They can perform a physical examination, take blood and tissue samples, and potentially run other tests to determine the cause and recommend appropriate treatment.
Please remember: It's dangerous to self-diagnose your horse's health.