Hi Daria,
interestingly enough, Ca/Ph ratio isn’t even discussed in the discussion of diet for growing large/giant breeds in Applied Veterinary Clinical Nutrition 2012. Nor is a specific ratio mentioned in recommendations for large breed growth. Dr. Larsen ACVN in an article on feeding large breed puppies writes “The ratio of calcium to phosphorus should be approximately 1:1 to 1.5; however, absolute amounts of each nutrient appear to be more important than the ratio per se.8 Clinical experience supports this, as developmental problems with extreme ratios in the presence of adequate dietary concentrations of calcium and phosphorus have not been reported.”
Based on those sources I personally don’t draw a line in the sand in regards to ratios during large breed growth.
