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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

The Value of Pregnancy Testing

When allowing for a biannual calving system, Tronstad and Gum found that younger open cows should be kept under certain market conditions. This suggests that pregnancy testing doesn't always have economic merit. The value of pregnancy testing is determined by subtracting the best uniform culling decision (e.g., keep all) from the best return generated after applying a different decision to open and pregnant cows. Refer to the tutorial of "Management Alternatives" for a description of the six possible culling decisions. The optimal decision is the highest value attained from applying the same decision to all cows and a different decision to open and pregnant cows, assuming a pregnancy test cost of $2 per head. The value of pregnancy testing varies depending on market prices, cow age, calving season (spring or fall), the cost differential between spring and fall calving, and recent cow fertility. Whether a cow has a sale calf at her side or no calf at side is the information used for recent cow fertility. Cows that were sound with a newborn calf at side were automatically kept in the herd.

The article "Value of Pregnancy Testing" (pdf file, 386 kb) describes these items in greater detail.

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