Seasonal Effects on Birth Weight
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                                 Late Winter   Spring
                                   Calving     Calving
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Beginning of the calving season	 February 13   March 12
Average birth date                 March 7     April 5
Birth weight                      89.7 lbs.    86.0 lbs.
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Birth weights of calves enrolled in the CHAPS program.

Dickinson Research Extension Center 2003 Annual report - 
Effect of calving season on cow/calf production in the 
Northern Great Plains - calf performance J.C. Clement, 
W.W. Poland, and K. Ringwall