Value in pregnancy testing cows

By Arden Wohlers DVM
Extension Veterinarian
University of Nebraska Panhandle Research and Education Center

This is shaping up to be a year when determining whether a cow is with calf or not could help in making a very crucial economic decision. The extended drought continues to put pressure on grass resources. This is resulting in many ranchers having very limited winter grazing available. The drought has also limited the amount of harvested forage for winter feeding. The resulting price of harvested forage may be double that of one year ago.

Pregnancy testing in the fall to discover and market the cows that will not produce a calf in the spring saves on winter feed costs. This year some producers may need to spend $50 more than the average of $120 to $150 that they usually need to fed a cow over the winter. Some years when grass is plentiful and harvested forage is less costly it can actually be profitable to keep nonpregnant cows and market them in the spring when the seasonal market for cows may be 5 to 10 cents a pound higher. This extra value may even be improved because of increased weight gain do to the abundant feed in those years. That does not appear to be the case this year. The opportunity to individually examine each cow for other problems such as cancer eye, damaged udders, and lameness is an added benefit of pregnancy testing. If there is a reproductive failure in the herd due to subfertile bulls or reproductive disease, corrections can be made before the next breeding season. There is also the opportunity to manage the calving herd more effectively by separating early calving cows from late calving cows. This is the year to wean calves and make the necessary culls from the cow herd early.

Pregnancy testing of cows by rectal palpation is a skill that became widely used in the 1960’s. This was a skill that came into veterinary practice after the arm length palpation sleeve was made available. An experienced palpater can confirm a pregnancy after 40 days of gestation and can estimate a cow's due date by measuring body parts of the fetus. During the 1990’s it became practical to use ultrasound for pregnancy testing in cattle. This improvement allowed a diagnosis to be made a couple of weeks earlier and was more accurate at estimating the due date. A further advantage of ultrasound was that the calf’s sex could be determined during the appropriate period of gestation. Both palpation and ultrasound testing can be performed on 60 to 100 cows per hour. Pregnancy test kits are available for measuring progesterone levels or glycoprotein associated with pregnancy. The kits can be used on serum or milk, but require more time to perform. Although these tests have been used in dairy herds they are generally considered impractical for beef cow ranches in the West.

Ranchers have unique operations and need to evaluate their own feed resources, access to alternative feed, and debt load. They then need to determine the least profitable cows to eliminate from the herd. Well thought out decisions will have to be made to have the business survive this temporary adversity of drought.

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