Yes, however there is some research that suggests excessive calcium may
be a factor in oseochondrosis and hypercalcitoninism. Excessive
phosphorus has been implicated in hyperparathyroidism, even when the
Ca:p ratio was adequate. Excessive protein contributes to higher
ammonia levels, which may "bottleneck" energy metabolism, and may be a
factor in tying up. Also, excessive protein has been shown to decrease
speed of racing Thoroughbreds, while requiring more water intake to get
rid of all that nitrogen. If a horse is fighting dehydration during a
ride anyway, I'd rather he didn't have to use that water making ammonia.
Also, more ammonia means more urine, stinkier stalls, more bedding
costs. Finally, protein is the most expensive nutrient, so feeding
excessive amounts is not cost-effective, especially if a better, more
balanced ration can be formulated that provides the same benefits and
less of the detriments.
Susan Evans