My longhorn is mostly all white with some black speckles... she is my pasture ornament... have a pure black heifer ( one of twins, other one died) that is being bred now. Had a white bull calf with the black points, last year and is a CHUNK, looks like a white park... he will be beef for me next year. I have always killed a jersey or jersey cross for beef the last 30 years. This year she has a black bull calf... Her calves will wean off at 4-450 easy and she doesn't weigh 850 with her horns. We use good black bulls, and she has had 2 "white" calves, and now 4 black calves in 5 calvings... and has backed up over 6 months until this year that we now are putting in the bulls and pulling them at this pasture with the breeding heifers. Used to use this pasture to keep a bull at simply because there was extra grass and it was a "catchall" for some different cattle.
So, yeah you might take a hit on the calves for color, but our black bulls have thrown more black than white on her coloring; however, since your bull is colored, my guess is you will get lots of color...