The Last Light Horse by Dianne Wolfer
 
The fourth and final book in the Light series, which began with Lighthouse Girl and includes the CBCA shortlisted Lighthorse Boy.

There were 136,000 Australian horses sent to fight during the First World War. Just one came home. From the high country of Victoria to the desert sand of Egypt, from the waters off Gallipoli to the battlefields of France, this is the extraordinary story of Sandy, the only returning warhorse.