Colostrum quality isn't purely random, it's shaped by factors producers can actually influence or at least anticipate. This study looked at how colostrum volume, the delay between calving and first milking, and photoperiod (day length) all affect colostral IgG concentration in dairy cows. For producers trying to predict or improve colostrum quality before calving even happens, this points to management levers beyond just the cow herself.
"Effect of colostral volume, interval between calving and first milking, and photoperiod on colostral IgG concentrations in dairy cows" — D.E. Morin, S.V. Nelson, E.D. Reid, D.W. Nagy, G.E. Dahl, P.D. Constable. J Am Vet Med Assoc. 2010;237(4):420-428.