Pretty clearly, cattle trucks and horse boxes are essential aspects of a pre-1965 layout - in some areas up to pre-75. In other words, before and during the entirety of the grey’n’green and black’n’tan eras.
Certainly in the case of cattle trucks, just as essential as a corrugated open wagon, a J15, a 141 and an “H” van.
Now for a Midland six-wheeler!