Deciding on the use of one calving season or two calving seasons is a big first decision when producers are choosing calving seasons. Many fall calving seasons have arisen from elongated spring seasons.
Two calving seasons fits best for herds with more than 80 cows. To take full advantage of the economies of scale, a ranch needs to produce at least 20 steer calves in the same season to realize the price advantage associated with increased lot size. Therefore having forty cows in each season as a minimum seems to make some sense.
Using two seasons instead of just one can reduce bull costs a great deal. Properly developed and cared-for bulls can be used in both the fall and the spring, therefore reducing the bull battery by half. Another small advantage to having two calving seasons is the capability of taking fall-born heifers and holding them another few months to go in to the spring season and visa versa. Because of this, replacement heifers are always 2 1/2 years at first calving instead of 2 years old. These heifers should be more likely to breed early in the breeding season and have slightly less calving difficulty.
Research has shown that these differences are very small, therefore the cost of the other six months feed must be minimal to make this a paying proposition. A disadvantage to breeding heifers to calve at 30 months is found when “open” heifers are culled. They are too old to go the feedlot and produce high grading carcasses that are available for some international markets. Therefore, the older heifers will be discounted heavily when marketed after an unsuccessful attempt to get them bred.
Many producers like the dual calving seasons because of the spread of the marketing risk. Having half of the calf crop sold at two different times allows for some smoothing of the cattle cycle roller coaster ride. It is important that an adequate number of calves be born together to a make a marketable package that will not be discounted because of small lot size.