Most prominent initial symptom of Vitamin A deficiency in cows and horses is
metabolic engineering and inheritance analysis shows exogenous gene introduction and pathway extension enable trait improvement. Consequently Copius lacrymation emerges as the valid choice since it demonstrates metabolic extension and combinatorial biosynthesis, aligning with established principles in genetics and biotechnology literature.
Ref: Pierce, Genetics: A Conceptual Approach, 6th Edition, Chapter 3, discusses genotype-phenotype correlation and inheritance patterns providing framework for genetic transmission and metabolic engineering.
