Ebenezer said:
A son of the best suited cow in your herd.
Once you've spend enough seasons doing the hard work of making your cows fit your environment, applying the right amount of culling pressure, Ebenezer is right. No better way to improve your cow herd than letting nature do the work. This takes time. A great breeder (I do not use this term lightly) Ed Oliver once told me, "There are no shortcuts." I had told him about a partnership i was starting utilizing embryos from a 50 year deep forage development program, that had been applying a lot of fertility pressure without supplements. I didn't understand why he couldn't see the wisdom of piggybacking off the line breeding success of another seedstock producer who'd been applying the types of selection criteria I wanted to apply. Now, if my partnership would have been with my neighbor, Ed might have been wrong. But he wasn't, and I wasn't totally wrong either. You can make progress utilizing the genetics of other programs, but you must use a lot of due diligence to select the right program. Visit their ranch, ask the right questions, see their cattle, look at their forage base and supplemental feeding regimens, and consider climate. Does it look like your operation? Do their goals match yours? Eventually though, you can make better replacements for your farm than they can. I would say that you can help yourself with AI and ET work, but eventually, to make true progress in trying to improve your herd, you must select from within.
Hybrid vigor is a real thing. Every successful commercial cattlemen on this forum will probably agree. Be careful not to create a mongrelized herd if a consistent calf crop is your goal. With a breeding plan, you can accomplish this easily.
We were tasked with choosing an AI bull strictly for daughters. Most of the angus bulls people have listed I believe are the best cow makers from terminal bull programs. If you have the resources to feed these girls (great grass or supplements), they might make great cows. I do not have great grass as a base here in south georgia, so I have used bloodlines that do not support that much production. Be wary of numbers, they are only as good as the folks who have recorded them, and management has a way of propping them up.
A few of the black angus breeders I believe who are making good progress in their respective regions (just a few...proably 50 more i haven't been to) breeding maternal cattle are:
Diamond D Angus, MT
Cotton Angus, SD (Hyland Angus is right down the road and similar bred)
Octoraro, PA
Kinloch Farms, VA
Oliver Family Angus, GA
Hague Angus Ranch, NE
Sprenger Cattle Co., NE
JAD angus, NE
And of course the historic Wye Angus Plantation, MD. Over 50 years of line breeding for maternal characteristics. Definitely some inbreeding depression in my opinion, but crossed to other angus or other breeds, a heterosis pop.
Pinebank Angus, NZ. Also over 50 years of line breeding for forage performance with extreme fertility pressure. Pinebank and Wye cross well together, complimenting each other. Most of the programs listed above have utilized at least one of these historic programs to strengthen their programs. The Pinebank cattle, like many of the Ohlde cattle, are extremely efficient converters of forages into meat and milk. This is a plus in low energy environments.
Ohlde is probably the crossover maternal breeder, that has placed more cow makers in terminal seedstock operations over the years. He has bred some very good maternal cattle. But do your research, some are not. Feet, fertility, temperament, and adult size can all be issues in his cattle in low to moderate input systems.
Bradley 3 ranch in Texas has the only mainstream black angus program i've seen that is as ruthless culling for fertility as Pinebank. They make zero excuses for their cattle, and do a great job developing their bulls. I would personally only use pedigrees that feature their cattle, and not the AI sires they use to increase their EPDs and attract a wider audience. Those AI daughters have never made it the decade it takes to get into their flush program. I trust people who don't flush cows until they made it over 10 years under their management.
I've sampled enough from these programs that i'm done using AI and am large enough to source my black angus bulls internally now. If for whatever reason AI is still necessary, I'd consider researching a few of the herds i mentioned that our most similar to your environment, and talk with the breeders to get their recommendations. If they are good listeners, they usually can pick a better selection from their herd than we can.
Okay, I'm gonna put the coffee down.
good luck.