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For more information about this area, please contact:

Russ Tronstad
Extension Economist

Phone: (520) 621-2425
Email: tronstad@ag.arizona.edu

Cow Culling Decision Support System

Biological Factors

Biological factors included in the model center around cow age and recent fertility. Biological estimates were obtained from the San Carlos Apache Experimental Research Registered Herford herd, located about 60 miles east of Globe, AZ. Range conditions are semiarid with an elevation of approximately 5,000 feet. Estimates of fertility, cow, and calf weights were made from individual cow records for the years, 1982 to 1989. Fertility encompasses three basic stages of 1) conception, 2) calving, and 3) survival of calves until weaning.

The article "Range Cow Culling: Herd Performance" (pdf file, 48 kb), describes these estimates in greater detail.

Note: The article requires Adobe Acrobat Reader, which can be downloaded for free from the Adobe website.