But it is only the beginning. Alfalfa is also very high in calcium and low in phosphorus. Older horses do nicely on a 2 to l ratio, and can stand up to 5 to l calcium to phosphorus. But lots of alfalfa for breakfast and dinner can push those ratios to disastrous proportions if there isn't another feed in the diet to correct the imbalance. Grain, which is high in phosphorus, low in calcium is nature's way of balancing the ratio.
Excessive calcium creates the first big series of problems.
It all starts with excessive calcium interfering with the function of the parathyroid gland. Excessive calcium can also result in hypothyroid horses, which are plump and shiny, but usually cranky, belligerent, resistant to bending and flexing, very lazy and emotionally unstable. Young horses being conditioned for performance or halter are often plagued by unsoundnesses, as well as training problems, simply because they are physically and emotionally troubled by thyroid or metabolic imbalances nutritionally-induced by alfalfa. Alfalfa can cause numerous training problems seemingly without solutions. Good, rich alfalfa will make young horses grow quickly and often end in epiphysitis, a joint condition which can have long lasting ill effects.