Why Have a Calving Season??

– Dr. Glenn Selk, Oklahoma State University Extension Cattle Reproduction Specialist

One of the most asked questions in the cattle industry in the Southern United States: If I “pull” the bulls out for part of the year, won’t I lose an opportunity to get a few calves? Should I leave the bull out with cows year-round?

Here is the answer: A research analysis of 394 ranch observations from the Texas, Oklahoma, and New Mexico SPA (standardized performance analysis) data set provided insight into the age old argument about “leaving the bull out” or having a defined breeding season. Oklahoma State University and Texas A&M Agricultural Economists (Parker, et al) presented a paper at the 2004 Southern Association of Agricultural Scientists. They found a positive relationship between number of days of the breeding season and the production cost per hundredweight of calf weaned.  Also they reported a negative relationship between number of days of the breeding season and pounds of calf weaned per cow per year.

The data suggested that for each day the breeding season was lengthened, the annual cost of producing a hundred pounds of weaned calf increased by 4.7 cents and pounds of calf weaned per cow per year decreased by 0.158 pounds.  The range of breeding seasons in the data set was from extremely short (less than one month) to 365 days or continuous presence of the bull.  The trend lines that resulted from the analysis of the data give us an opportunity to evaluate the economic importance of a defined breeding season.  The producer that leaves the bull out year-round (365 days) would sell 45.82 fewer pounds of calf per cow per year on the average than producers with a 75-day breeding season. That same producer would have $13.63 greater costs per hundredweight of weaned calf than the producer that used a 75-day breeding season. In this era of cost/price squeezes, a well-defined breeding and calving season provides a better opportunity to survive the volatility of cattle prices and input costs.