I have heard a lot of ideas about how to get cows bred but experience has taught me many of those hypotheses don't work.
After 35 years and 800,000 miles logged in five middle-Tennessee counties working with hundreds of beef producers who averaged less than 20 cows, it would be difficult for a veterinarian with a real interest in profitable animal agriculture to miss these stories. Further, I had plenty of my own preconceived ideas by the time I left vet school. Eventually, though, I cast aside most ideas because the evidence said few of them worked.
I have not seen or heard it all, but I am no longer a neophyte. I've seen constant feed, no feed, and everything in between. I've seen 30-day breeding seasons, 45-day seasons, year-around breeding, and everything in between. I even saw a fellow once who had a steer running with his cow herd, supposedly to keep them cycling every 17 to 21 days.
Several years ago I met a rancher from South Africa by the name of Ian Mitchell-Innes who was working about 1,500 cows. He had shortened his breeding season to 21 days and was using nearly 100% of his previous year's bull calf crop as his bull battery. He was turning in more than 600 bulls aged 14-5 months to breed his cow herd and replacement heifers. Incidentally, he said he did castrate the handful of dinks and freaks.
After listening to his thoughts several times the light began to dawn. It finally came to me that he was allowing nature to quickly bring his cow herd together phenotypically as to size, milk, production, fertility, early maturity, other maternal traits and environmental adaptation. I eventually decided he was onto something good. A new paradigm was before me. I now believe he was right.
Let's consider his program, or at least something similar, and I'll make a few remarks I think are worth remembering.
• It's low cost because there are no purchased-bull costs.
• Cows must be cycling in order to get pregnant.
• Short breeding seasons require radical culling, initially and for several years thereafter.
• High-milking and hard-keeping cows will go to town quickly.
• A handful of bulls can be left in the herd for several additional weeks and late-breeding cows can be retained initially or sold as bred cows or three-ways.
• Low forage-energy environments require a little supplemental energy for yearlings to breed at 14 to 15 months of age.
• Yearling bulls that are early maturing and have plenty of libido will do the majority of the breeding. The result will be offspring (both bulls and heifers) which are early maturing and show the correct masculine or feminine traits.
• If bull calves are weaned late, meaning 300 days or more, they have a hormonal growth advantage.
• The option to castrate bulls at 16 to 17 months is viable, with resulting steers fitting the contract description being sold 40 to 70 days after the breeding season.
• There is no law against selling bulls as proven breeding stock after three or four weeks service and training.
• Since zero dollars are spend on herd sires, AI or embryo transfer, it would be hard to lose much money.
• No money or effort will be spend on keeping bulls throughout the year.
No other program I have seen or heard of could make as fast environmental-genetic progress as this one. It makes nature do the selection pretty much as nature once did.
I would love to hear reports from sizable North American operations that have instituted Mitchell-Innes's breeding program.