This puppy was given milk replacer for three weeks in the first two months of its life because of illness in the dam. Does that explain this ocular pathology?
The simple answer is ‘yes’! There is a ring of opacified lens which has been laid down while the animal was fed its milk replacer. Its not quite clear what the pathogenesis of the cataract is, but it is likely to be an osmotic effect on developing lens fibres. Nutritional cataacts in timber wolves were attributed to an arginine deficincy and recently Ranz and colleagues reported two litters of puppies with just these ‘ring-like’ opacities (J Nutr 132:1688S-1689S)although they too attributed changes to deficiencies in specific amino acids in the milk. Previous studies have included that of Glaze and Blanchard reporting cataracts in a Samoyed litter (JAAHA 19:951-954) while Martin and Chambreau showed the changes in experimentally orphamed puppies (JAAHA 18:115-119).