Our cowherd at the end of June. We turned the bulls in with the cows on July 1st. This means they are due to start calving about April 8th. This is early enough for us as we remember early April snowstorms.
Cows have a tremendous ability to fluctuate their weight based mainly upon environmental conditions. Low-cost managers time the peak nutritional requirements of the cow with the time of peak nutrition in the environment. Put simply, calve in late spring.
May and June pastures in the driftless region are tremendous. Our cows gain at least 100 lbs. from calving in April and May until breeding in July.
The picture below shows a cow in excellent condition in the foreground. The background shows two cows engaged in homoerotic behavior. This is common for cows when they are ‘in heat’.
This is a good sign, because it shows the cow is ovulating. It takes good genetics and good management to keep cows on a yearly reproductive schedule. They need to calve, lactate, and have their reproductive tract return to normal so they can start cycling again.
Our breeding season last year was six weeks for the heifers and nine weeks for the cows. We only had two cows calve in the last week of calving, so I’m thinking of shortening our breeding season to eight weeks.
Ian Mitchell-Innes is a South African rancher I heard speak at a Mob Grazing seminar. He claims to have a 30 day breeding season. I wonder how short of a breeding season we could have.
Curiousfarmer 
If the breeding season is short, will you get any sleep in during calving?
Thanks, WSB for your question. Yes, I hope to sleep during calving season, and that brings me to a short post I was thinking of writing: “Sleeping During Calving.” https://curiousfarmer.com/2010/07/15/sleeping-during-calving/