Black Herefords are a composite at best... that's being nice. The "F1" mother will not be like a true red Hereford crossed to a Brahman.
I'm a little surprised the black and white dominated all the calves. If you give a Brahman any chance in a gene pool they will grey them, fade them, stripe them, or throw some tie died, cookies and cream, version of the colors. Even the purest of black Angus can get faded in to brown stripes. Same with the red and white of Herefords... it has multiple color variations. Both of those colors have been stabilized far longer than the black Herefords.
Well, Black Herefords are no more "composite breed trash" than any other 3/8ths Brahma like Brangus, Braford, Beefmaster, Sant Gertrudis etc. The Black Hereford has been a stabilized breed for about 20 years now. There is a youtube video that has been posted on these forums before, from Univ of Iowa about Heteratosis. It contains a chart of all the most common breeds, and the 2 British breeds that shared the least DNA, were the Angus and Herford. Much more genetic diversity than any of the Continental breeds., thus the maximum hybrid vigor. This is why the black baldies are so popular. The breeders that developed the Black Herford, used genetics from the best of the best of the Hereford, and the best of the best of Angus. You will find more "trash" among the average Herefords and the average Angus, than in the Black Hereford. By most accounts, the founders of the breed were successful in achieving their goal: preserving the docility and maternal traits of the Hereford, while incorporating the traits that make Angus #1. Those are better udders, better marbling, fewer foot and eye problems than Herefords, with the bonus of being homozygous for black, while tempering the tendency of Angus to b
e too good of a mother with new calves. The main focus of developing this breed, was to have cows and bulls to breed to angus cows and bulls for calves that you can guarantee will be black baldies.
I am attaching a pdf that
@Caustic Burno has shared before, that shows that the best cross with Bos taurus and bos indicus is Brahma and Herford, specifically, Brahma bulls on Hereford cows. Next is Brahma on Angus. So with black baldies being undeniably the best British cross breeds, and Br X Her being the best indicus x taurus cross, and Br x Ang being the 2nd best. there is no reason to think that an F1 Br x Black Hereford cow would not be as good...and most likely superior to... the Br x Her F1s.
I was a boy when people first brought Brahmas to my area of Ga. Most everyone that bought a Brahma bull had angus cows. I doubt many of then were registered Angus that were homozygous BB for black. But, I don't recall seeing many Br x Angus crosses that weren't black. And people had some Brahma cows that they bred to an angus, and probably most of them were grade angus bulls, most likely not tested Homozygous BB for black either, so they may have had some red or brown calves as well.
The 12 Black Hereford cows he bought were homozygous PP polled, and homozygous BB black. The Br bull he used is white and polled. The Brahma cows he uses are all registered and are white and polled. The BH semen he used, was from homozygous black and polled bulls. So, that was the reason the calves were all uniform black. He also bred some Brahma cows to registered Chi-Angus bulls.. about 30 I think...and these calves are all black too. Look just like an F1 Brangus, only bigger.
As far as using these F1 Brahma x Black Herfords as brood cows, they will be only heterazygous black. Using a homozygous black bull, you'd get all black calves, but so would you using regular F1 Brahma X Hereford cows. If your black bull isn't homozygous black, then you are as liable to get a different colored calf with these Br x B He as you would using Br x Hereford.
IF he and others actually do go ahead and pursue developing a Black Braford, then these will be homozygous for black cows, but I doubt I will be around to see them.