A low pressure system/change in the weather always seems to speed things up at calving time.

I shoot for May 1 start of calving +/- a few days. Bull goes in right around July 20th, depending on weather and what else is going on.

Like to get them all done in 2 cycles (around 45 days) which means done by about June 15. However my young, home-raised, bull is a real go-getter so I'm hoping to be done in May  this year.