Typically fall is the lowest market for cull cows in my area, but generally starts picking up in early spring. For example, I looked up my own personal cull cow receipts from fall 2007/spring 2008 (I didn't sell any personal culls for the fall 2008/spring 2009 time frame for comparison, or I would've used that as an example instead), and found my cull cows averaged 8 cents higher from culls I marketed the previous fall (approximately $100/head). I also looked up and found I've missed detecting an average of four head of opens per year over a six year average.
If I took time to calculate feed costs to feed four additional head, four additional months, vs the cost to pregnancy test the entire herd to detect an average of four additional opens over the years, I'd say I'm still money ahead to not preg check, especially if they appreciated in a spring market. If I were missing a lot more cows, that may not be the case. Maybe I'll do the math on a ten year average for fall vs spring cull cows prices and feed costs during the next snowstorm :shock: .
Yes, I have had one cow in six years not cycle. Veterinarians aren't 100% accurate either. She was sold during the June market, which is typically the highest cull cow market of the year in my area.
For now I can't justify spending the money or time pregnancy testing the entire herd to find a handful of opens. Like I previously stated, if I had a bunch coming into heat, I'd certainly be checking them. If I had cheaper winter feed costs, some years I would strongly consider holding my culls over until spring. Cull cows are an important part of revenue which should be marketed maximally as well. It's easy to just ship them every fall, but is that always smart?
I look through my cattle often during the fall, and detecting possible opens is convenient to do at that time. Also, I'm not looking after a large herd. It certainly isn't justifiable for everyone, but it has worked for me.