Mary was a beautiful Frederiksborger mare from a very old and important bloodline. She was born in 2022 and was trained in harness from an early age. Unfortunately, Mary had an accident where she fell on her left shoulder. This ended her driving career early. Because of her valuable bloodlines she was used as a broodmare. After giving this world a few beautiful foals, her behaviour changed. She was no longer manageable in a mare herd and was also sour to her own foals. She was given an early retirement, but her behaviour continued to deteriorate. She was eventually presented for dissection in 2016. 

The assessment showed that Mary had difficulty moving. As expected, this was mainly in her left shoulder. The main findings were the problems in her neck, left shoulder and fore legs. Her hindquarters and spine also showed signs of physical discomfort. We could link some of these findings back to the fall on her left shoulder, but the cause of some was still unclear. We hoped to find out more during the dissection. 

The dissection revealed a secret we never thought we’d find. The bone in almost every joint in her neck was beginning to grow into abnormal shapes. This must have been highly uncomfortable and explains why it was so difficult for her to flex. She also had a fused growth plate under her lumbar vertebra that had grown into bone proliferations. Mary tried to tell us something through her behaviour. When a horse resists flexion, there is often a reason. In some cases, like Mary’s, it was simply impossible for her. 

Hopefully this case has inspired you and given you new insights so that Mary’s story will not be forgotten. The more horses we can view and compare, the more we learn! Do you want access to more stories like Mary’s? You can them in Equinestudies’ online course ‘The Horse Inside Out’.