Glenn Selk Reminds Cow Calf Producers- Fall Calving Season Has Arrived

By Glenn Selk

"Fall-calving season is here.  In fact, the start of the fall calving season often begins before some producers expect it.  The target date for the beginning of fall calving very often is September 1.  Most printed gestation tables predict that calving will take place 283 days (some 285 days) after artificial insemination or natural breeding.  Cows and heifers that gestate in hot weather will often calve a few days earlier than expected.
 

"Oklahoma State University physiologists studied early fall (August) and late fall (October) calving cows. Data from two successive years were combined for 60 Angus X Hereford crossbred cows. The “early” and “late” fall calving cows had been artificially inseminated in early November or early January, respectively. Semen from the same sire was used for all cows. All cows were exposed to a single cleanup bull for 35 days at 4 days after the AI season.

The weather prior to calving was significantly different for late pregnancy in the two groups. The average maximum temperature the week before calving was 93 degrees F. for the “early” fall group. The average maximum temperature the week before parturition in the “late” calving group was 66 degrees F. There was a 100% survival rate for calves in both groups and both groups of cows had very high re-breeding rates (90% and 92%, respectively).