Antibodies get most of the attention when it comes to colostrum quality, but the full protein picture is a lot bigger than IgG alone. This study mapped out the complete proteome of colostrum and transition milk, comparing first-time calvers against cows on later lactations to see how protein makeup differs. For producers thinking about colostrum quality beyond a single Brix reading, this is the kind of deeper data behind what actually varies cow to cow.
"Characterization of the colostrum and transition milk proteomes from primiparous and multiparous Holstein dairy cows" — M.J. Fahey, A.J. Fischer, M.A. Steele, S.L. Greenwood. J Dairy Sci. 2020 Feb;103(2):1993-2005.