In his practice veterinarian Gerrit Kampman frequently comes across Friesians with low heels. He says: ‘A Friesian mare with a serious lameness was taken to my clinic. It was a mare already a bit advanced in age who had also had a few foals and was regularly used for driven work. This mare presented a clinical image of swelling around the Achilles tendon, low heels and extreme straight stance of the hind legs.’
In some cases such a clinical picture manifests itself as an acute problem but usually develops more gradually and ultimately leads to lameness, as was the case with this mare. Swelling surrounding the Achilles tendon often involves more structures of the soft tissues in the area of the hock. The hock joint itself shows no overfilling but the swelling originates in the soft tissues around the hock, tendon sheath of the Achilles tendon and for example the suspensory ligament itself which attaches just below the hock. The cause of the swelling is not entirely clear. It could be related to hormonal changes during pregnancy because one of the hormones produced in this period is relaxine.
Influence of relaxine
‘Relaxine is particularly important during the later stages of pregnancy because it relaxes and weakens the ligaments around the pelvis to prepare for foaling. However, relaxine also causes increased weakening of muscles, tendons and ligaments elsewhere in the body. So this may also have an influence on the ligaments, suspensory ligaments and tendon tissues surrounding the hock joint and cause reduced flexion power of the soft tissues. The ligaments then can literally no longer support the horse. This is a progressive condition: when the mare gets older the fetlock will progressively move further downwards. Therapy consists of made-to-measure shoeing and systemic support by administering painkillers and anti-inflammatories. Other breeds are also affected by this condition but unfortunately it is much more common in the Friesian breed,’ Kampman states.
Read the full story in the July issue of Phryso.