Concern about protein causing developmental bone problems in large-breed puppies has led some breeders to reduce the amount of protein they fed. However, in research published in 1993 based on studies of Great Dane puppies at Utrecht University in the Netherlands, it was shown that dietary protein does not contribute to these problems.”
“Herman A. Hazewinkel, D.V.M., Ph.D., professor of veterinary medicine at Utrecht University, led the research that found no detrimental effects from protein levels up to 32 percent of the diet. However, puppies fed a diet of only 15 percent protein showed evidence of inadequate protein intake.”
“Too low protein decreases the growth rate of puppies and also their immunological response,” Hazewinkel says. “This is true for large- and small-breed puppies. An adequate protein level should be higher than 15 percent.”
“This study, conducted in young Great Danes during their first half-year of life, concluded that dietary protein increased to 32 percent does not negatively affect skeletal or cartilage development in these dogs. The research also confirmed that dietary protein did not have detrimental effects on liver and kidney functioning.”
So the conclusion of the above referenced research stresses the need for high quality protein to achieve the best growth and immune systems. No proof was found that protein amounts affect skeletal growth in any adverse, except when using too little or too poor quality.
http://www.eukanuba-eu.com
This article reiterates that high protein does not cause OCD or HD, in either the hips or elbows:
Research into the growth of Great Danes (Nap RC, The Netherlands,) has shown that the protein level of a diet has no significant influence on skeletal development. High protein intake does not result in increased risk for OCD or HD, and there is no effect on the development in the longitudinal growth of the bone.”
Additionally, while protein does not cause orthopedic problems, other nutrients can.
http://www.vetmed.ucdavis.edu
“In addition to excessive calcium intake, researchers have shown that over nutrition can also initiate these disturbances in skeletal maturation and growth. An excess protein intake, without an excess of other nutrients revealed NOT to influence skeletal maturation and growth in growing Great Danes (Ref. 2).”
This would include supplementation of calcium to processed diets, or could occur when feeding raw diets to puppies that are more than 50% raw meaty bones. Calcium amounts are adequate in commercial pet foods, and a diet of no more than 40% to 50% raw meaty bones is an appropriate amount for a growing puppy. This article also concludes that certain breeds may require less calcium than others for proper growth: