|Hart, Richard - USDA-ARS (RETIRED)|
|Waggoner, James - UNIVERSITY OF WYOMING|
|Smith, Michael - UNIVERSITY OF WYOMING|
Submitted to: Society for Range Management Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: September 1, 2003
Publication Date: January 5, 2004
Citation: Derner, J.D., Hart, R., Waggoner, J., Smith, M. 2004. Calving date, weaning date and stocking rate in the northern mixed-grass prairie: which combination is the best?. Society for Range Management Meeting Abstracts. No. 77. Technical Abstract: Cow-calf producers in the northern mixed-grass prairie traditionally have calved in March, weaned at 180 days and employed moderate stocking rates during the grazing season. Yet, additional combinations of calving dates, weaning dates and stocking rates are viable management options that may be of interest to producers. A six-year (1995-2001) study was conducted in northern mixed-grass prairie at the High Plains Grasslands Research Station to evaluate Hereford cow and calf gains during the grazing season (early June to November) from combinations of stocking rate [moderate (6.29 ha per cow-calf pair) or heavy (5.14 ha per pair)], calving date (March or May) and weaning date (150 or 180 days). Weaning weights were reduced by 12% with early weaning of March-born calves (191 vs 218 kg, early vs. late), but only 6% with early weaning of May-born calves (189 vs. 200 kg). Stocking rate did not affect weaning weight or cow weights in November. Cow weights at the end of the grazing season were 13% greater for March- than May-calving cows (586 vs. 517 kg). Decreased spring feed requirements for May-calving cows may compensate for increased feed needed to make up for lower summer gains. Calf mortality may be lower in May-calving than March-calving cows, primarily because of better weather conditions. If these hypotheses are supported by further research, early weaning of May-born, but not March-born, calves is a viable management strategy for producers in the northern mixed-grass prairie.