We calve about 175 + cows a year, split into pretty much equal spring and fall calving. Have been getting 65-75% heifers, and it has nothing to do with particular bulls as we use 5-8 bulls, one bull per pasture or group and 10 to 40 per group depending on the pastures and conditions.
We do a 2 time culling of calves/heifers, sometimes 3 "look ats". First culling comes when we are ready to wean/ship calves. Disposition/attitude and confirmation, what ever reason we don't like them. Then the ones we like will get a 2nd look usually when they come off pasture or get moved for whatever reason. We keep about 15-20 from the first culling, maybe 8-15 from the second look at. So we keep somewhere in the neighborhood of 20 +/- per year .
There is little to no difference in the fall or spring born calves as we do not calve our heifers until they are about 27-30 months. So they all go through 2 winters before they have their first calf. Used to only calve heifers in the spring but have started calving a fall group; but want those calves on the ground before the first of Oct so they are growing good before the cold weather can affect their condition too much. Calves will get a little creep feeding, learning to come in through the creep gate to feed a couple of times a week, and take a little pressure off the first time heifers to provide all their nutrition.
Yes it also depends on the markets. The couple of years that heifers were in the $2.00 plus per pound range for 4-5 wts, we kept about half or maybe 7-10 per year. In fact one year we kept 4 and sent a couple that I liked but could not justify letting that much money sit in my pasture. I factored in who they were out of and the age of the momma cow and if it were likely she would still be around for a couple more calves, so a possibility of another heifer to keep.
We also buy and sell some cows, but overall we cull about 10% of the herd yearly...mostly due to age/ poor milking ability to raise a good calf that year..... or attitude, or lack of rebreeding.
We keep any cow that breeds and calves yearly and raises a decent calf until there is a problem. Many of our cows are in the 10-14 year range. Age is not a single factor for us for culling. It is one strike, but they have to either not milk and raise a good calf that year, or not breed back, or develop feet/leg problems...or something. I know one farmer that will sell cows regularly over 8-9 years old. I have bought many of them, and gotten 2-6 more calves out of them. And kept some of the heifers off them.
We are commercial, so a little different focus than a purebred or registered breeder. I also do some AI breeding, and have some dairy animals that I use as nurse cows. I lost an old cow with a 1 1/2 month old calf on her, the calf started stealing off 2 other cows who have their 2nd calves on them, so the 2 will raise the 3 calves. They all look good and should do okay. They were both very late in our spring group, so will get moved back into the fall group and will have a couple extra months to get their bodies in condition before the bulls go in in Nov., so raising the orphan should not hurt them.
