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A 32-Day Breeding Season Works

My husband and I have been raising cattle on a small mountain ranch for 43 years — a ranch with very little hay ground, lots of steep native pasture, and four months of summer grazing on public range. Our basic cattle management included early calving (to use the range with cow-calf pairs, and to have the cows bred to our own bulls before they went to public pasture), and early weaning when the cows come off range, so the dry cows can use our fall pasture until it snows under in late November or December. Our fall pastures are best used by dry cows; the cows do well on these native bunchgrasses with no supplement except salt.

Historically, traditional spring calving was not very profitable in our region. Earlier ranchers on this creek calved in March and April, with quite a few late calves arriving in May. They bred their cows on the range — which always resulted in a more strung-out calving because bulls didn’t always find the in-heat cows in timely manner in such a large, rugged area. Ranchers typically weaned 350-to 400-pound-calves in the fall. There was very little herd improvement; ranchers ran cattle together and some had poor-quality bulls.

When my husband and I started here in 1967 we discovered there were a lot of bad scour “bugs” on this place. We decided to get away from wet spring weather calving, and calve earlier so we could get most our cows bred to our own bulls before they went to summer range. We had less scours in early-born calves, and more calves sired by our own bulls, increasing weaning weights and improving the quality of our replacement heifers. We decided to shorten our breeding season even more, to breed all our cows at home.

We achieved the goal in 1975 when we got a new range neighbour who also liked early calving. By then it was just us and him on our range allotment (instead of eight different permittees), and we agreed to bring all bulls home early, putting a definite cut-off date on calving. By 1986 we didn’t turn bulls out on the range at all, shortening to a 45-day breeding season. Calving was January 5 through February 22.

Winter calving, with the cows supervised because of cold weather, cut our birth losses from four per cent (our average loss when field calving in March and April) to less than one percent — most years we had no losses at all. The short calving season also allowed us and the cows to recover quickly, with the cows ready to breed back all at once. Our home-raised cows rebred fast (because we never keep a heifer that doesn’t become pregnant in our short breeding season, and thus selected for high fertility over many generations of cows), and by 1988 we realized we could cut the breeding season even shorter. Why get up at night during the last two weeks of calving for only three cows? So we left the bulls in for only 32 days (end of March through end of April), and this short breeding season worked well.


A breeding season this short works because our crossbred cows are very fertile, due to 30 years of careful selection, keeping only those that rebreed quickly on very ordinary feeds. Our cows are not as fat as some beef cows because they are milking well to raise big calves, but they seem to have enough internal fat (where it counts) to rebreed.

The bottom line in our operation is what a cow produces — a big calf year after year, without coming up open — not how she looks. A cow that has to put a lot of weight on herself before she’ll feed a calf and breed back doesn’t stay in our herd. Most of our cows weigh 900 to 1,100 pounds, and wean 600-pound calves. Over the years, some of our best cows didn’t weigh more than 950, yet weaned calves close to 700 pounds. We like the cows that put it on their calves instead of themselves, as long as they can rebreed in our short season.


Cows must be adequately fed to breed quickly, but this doesn’t mean costly high-energy feed. Our herd must perform well on the feeds we grow — native bunchgrasses and wild hay. We buy a little alfalfa for heifers (weanlings and first calvers that need the extra protein while still growing). All the yearlings and most of the two year olds suckling their first calves will breed in 32 days. We don’t feed any grain (not even to young bulls; we grow them on hay and pasture).


If you want cows to breed quickly, you also must have the bulls and breeding pastures to make it work. We like the vigour and fertility of our home-raised crossbred bulls. They have very fertile dams, and are never hindered by overfeeding. Overweight young bulls that come off feed/gain tests are not only too fleshy for good stamina in the breeding pasture (and may develop foot and leg problems due to overfeeding), but also have lower sperm numbers and quality due to too much fat deposited in the scrotum. You need a very fertile bull with lots of sex drive and athletic ability — an active, aggressive breeder that’s not too fat.

We divide the cows into several small breeding groups (20 to 40 cows in a group) in small pastures — better conditions for getting every cow bred on first heat than in large pastures or on range. In the last few years we’ve sold most of our cows to our son, cutting down our herd numbers to where we can run them at home in summer and let our son use the summer range. Now in our old age we don’t have to calve in winter — we can breed them later on our own home pastures. But we still prefer the short, intensive breeding and calving season, and still use the methods we learned while trying to get them all bred during April.

We have one to three bulls in each group. This gives more chance of getting every cow bred. When we had 170 to 180 cows and 30 to 40 heifers, some days there would be 12 to 20 animals in heat at once, but only three or four in any one group. If they were all together in one huge range pasture, some might get missed or the bulls might be fighting over certain cows and

not getting them all bred. When you have that many bulls in the same pasture, there’s also more risk of having bulls hurt.

But even with small breeding groups, you have to pay attention to what’s happening, and watch those bulls. If there are two bulls in a group they may just fight and keep each other from breeding. One or three is better. With three bulls, one can breed the cow while the other two are fighting. If there’s just one bull in a group, he must be very dependable, and we make sure he is getting his cows bred — especially if there are three or four in heat at once. A yearling bull may tire if he has to breed several cows in one day, especially if he concentrates all his energies on just one cow, as some yearlings do. An older bull may quit, yet fight off the younger ones and keep them from breeding. You have to know what is happening and whether the cows are actually getting bred; you have to see them more than once a day.

If a cow gets missed during a 60-day breeding season, she’ll have more chances. But in a short breeding season, she may not get a second chance. We constantly check to ensure bulls are doing their job, making changes if they aren’t — before cows get missed. Sometimes a bull gets tired or injured and quits, or keeps trying but won’t complete the job. You won’t know unless you are checking. Our bulls get worked very hard for a short time, and there’s no room for error. For example, in April 1993 more than half of our 37 yearling heifers and more than a third of our 170 cows were bred during the first eight days the bulls were with the cows, but we had to do some bull switching in one group when two yearling bulls temporarily wore out.

Our short breeding season worked well because we had several small groups, lots of bulls (we could take one out if he got injured or tired, and replace him with a closely related bull — raising our own bulls enables us to have a few “spares”) and we keep track of what’s happening. This makes for intensive management during breeding season, but it’s nice the next calving season, having the babies come quickly and getting it done.

For us, January calving and a short breeding season, which evolved over time as we developed fertile cows that could do it, was most profitable because it allowed us to selectively breed our cows at home to a selected bull (or full brothers) instead of indiscriminately on the range, to create the most efficient animals for our conditions, while cutting birth losses and scour losses. It also enabled us to use our abundant fall pasture with dry cows, and be off hayfields in the spring two weeks earlier (taking the bulls out of the breeding groups and putting all the cows and calves on our hill pastures before they went to the range). For us, the short breeding season was the answer to a lot of problems and enabled us use our ranch feed to best advantage.

Heather Smith Thomas ranches with her husband Lynn near Salmon, Idaho. Contact her at 208-756-2841

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