The problem with the best grass time for some is you end up with the worst calf marketing time.  Have to balance the two. Here fall markets are normally lowest and can be very off some years. Also here it is too hot to breed in summer. When i had cow/ calf i tried to calve in January, hay and supplemental cereal rye thru feb, then sell in August before market dropped. Now i buy fall stockers and sell the following summer when the fescue grass runs out or it get too hot  - again trying to manage marketing time.