Fall Calving in the Cornbelt: Nutritional Considerations

06:48PM Oct 14, 2014
BT Cow Calf Summer
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Second in the three-part series, "Fall Calving in the Cornbelt"
By: Patrick Gunn, ISU Extension cow-calf specialist and Joe Sellers, ISU Extension beef program specialist

When is fall calving? As we talk to producers in Iowa, it seems some consider the fall-calving season to occur from August 15 – October 31, while others assume September 15 to November 1 is the right time frame. (Hopefully adding a fall calving group is not just moving to a “continuous” calving season – this needs to be a separate management group!)

Regardless of what time period constitutes fall calving, it is safe to say that it's being implemented by more producers, particularly in the fescue region of the Cornbelt. Fall-calving beef cows usually can perform very well grazing summer fescue pastures during gestation; however, spring-calving cows grazing the same pasture while lactating and attempting to rebreed may experience difficulties.

University trials and producer testimonials support how changing the calving season can be a strategy to improve production output when utilizing endophyte-infected fescue pastures. However, altering the calving season will directly impact nutritional requirements at a given time of the year. These differences in stage of production are critical to consider as you evaluate the seasonal feed requirements of fall-calving cows. In addition, when the cows calve relative to extremes in temperature will impact winter nutritional needs.

The type and availability of feed resources you have may influence how fall-calving can fit for you. In the middle of winter, lactating beef cows require ten percent more energy per pound of diet, and seven percent more crude protein, compared to dry cows in the last third of pregnancy during the same time of the year. If you are relying on grazing pairs on low quality forages (such as cornstalks) in the winter with little supplementation, it may be difficult to meet the cow and calf requirements. However, if you can stockpile high quality forages (fescue/red clover), it is possible that these increased nutritional requirements can be met by pasture for most of the winter. As always, forage testing and ration analysis is critical.

If you can wean calves prior to the extreme weather, it will greatly reduce the feed requirements for the cow. We will talk more about early weaning in a future article - but removing the calves can allow the mature cows to regain weight on poorer quality roughages. Dry cows in early pregnancy will need diets with 14.5% less protein per pound of ration, and 21% less energy, compared to momma cows with calves at side.

As you evaluate your calving system decisions and ration choices, contact your local Iowa State University Extension and Outreach beef specialist to develop rations that fit your operation.