Effect of Calving Time and Weaning Time on Cow and Calf Performance - A Preliminary Report

Cows grazing native range year round were allotted to 3 management systems: 1.) A calving season starting in mid March with calves weaned in late October; 2) A calving season starting in mid March with calves weaned in mid September; and 3) A calving season starting early May with calves weaned in late October. After 2 years of the study, pregnancy rate and calving interval were not affected by management system. Average weaning weight was the highest for the March calving/October weaned group in both years. In the first year of the study, severe winter weather caused a lower calf survival to weaning for the March calving groups compared to the May calving group. This resulted in similar pounds of calf weaned per cow exposed for the March calving/October weaned and May calving1October weaned groups. Estimated income per exposed female was similar for these two groups. In the second year of the study, calf death loss was not affected by calving time. The heavier weaning weights of the March calving /October weaned group resulted in more pounds weaned per cow exposed and $30 greater income per exposed female. The potential to reduce costs for winterfeed, equipment, calving facilities and labor would favor later calving and must be considered