This forage is not fit to feed to horses and will invariably cause many cases of heaves. Sixty head of brood mares on one farm alone were diagnosed with heaves from just such a cause. This brings us to another point about heaves. I have often heard that a mare with the heaves will not become pregnant or carry a foal to full term. This is not true.
Many mares suffering from heaves become pregnant year after year and deliver fine, healthy foals.
Stallions with the heaves can and will remain sound breeders for many years, far up into what is considered old age for a horse. I am thinking of at least two famous, well-known draft stallions who had heaves, yet produced offspring for many years. Now that you understand something about the causes of heaves in horses, we can surely see that prevention of the condition is relatively easy. This is a disease of horses that is much easier to prevent than to cure.