Preg Check Your Cows . . . Please!

By : Dr. Les Anderson, Beef Extension Specialist, University of Kentucky

It’s weaning time and I hope most of you are planning your herd “preg check”. If you have not incorporated this management practice in the past, please do so this year so that you won’t be feed non-productive females this fall and winter. When it comes time to cull cows from your herd, pregnancy status is one of the first criteria that will determine whether a cow stays in the country or goes to town.

According to the results of a survey conducted by the National Animal Health Monitoring System, fewer than 20 percent of beef cow calf producers used pregnancy testing or palpation in their herd. However, the benefits of this practice are fairly simple to realize. First of all, pregnancy diagnosis allows producers to identify “open” or nonpregnant cows. Compare the roughly $5 per head cost of a pregnancy exam with the $100-200 per head cost of hay alone to feed an open cow through the winter (if you can find hay for $30 per roll). It’s easy to see that pregnancy testing quickly pays for itself.

Second, pregnancy testing will provide a producer an estimation of when cows will be calving based on the age of the fetus at the time of the pregnancy exam. An average calving date can be calculated and the producer can use this information to better supplement, the cows through the winter. Remember, the nutrient needs of cows vary throughout their production cycle; cows nutrient requirements are highest immediately before and after calving and are lowest in the second period of pregnancy. Knowledge of the stage of pregnancy can help producers make efficient feeding decisions. For example, most producers will have hay of varying qualities in storage. Since cows in the second period of their pregnancy require less nutrients, producers can target their lower quality feedstuffs for the time when their cows nutrient requirements are the lowest. Alternatively, producers can save their best quality feedstuffs for the post-calving period when a cow’s nutrient requirements are the highest. Thus, obtaining the pregnancy status of your cowherd will allow a producer to adjust the supplementation in a timelier manner.

Finally, if the herd needs to be culled and pregnant cows need to be sold due to drought and lack of pasture, knowing the pregnancy status of the cows will be appealing to potential buyers. Buyers will be looking to purchase cows that will calve closely in line with the cows already in their own herds.

Pregnancy diagnosis is a quick and simple procedure. Three practical methods for pregnancy diagnosis can be used in beef cattle: 1) rectal palpation and 2) transrectal ultrasonography 3) blood sampling. Rectal palpation is most common and is an accurate form of pregnancy diagnosis that can be performed after day 45 of pregnancy. Many veterinarians are proficient at rectal palpation, and this procedure requires little time in the squeeze chute. Transrectal ultrasonography, commonly referred to as ultrasound, can be used to detect pregnancy as early as 28 days with a high degree of accuracy. This method can be employed just as quickly as rectal palpation when done by a skilled technician and may provide additional information that cannot be determined by rectal palpation. Using transrectal ultrasonography, the technician is actually “looking” at the fetus and can determine the viability of the fetus and the incidence of twins. It is also possible to determine the sex of the fetus between days 60 and 90 of pregnancy.

The blood test method to determine pregnancy is simple and accurate. First, a blood sampling kit needs to be ordered from the company. Usually, the cost is about $1.50-1.60 per cow for the kit. All the tubes should be labeled according to the instructions in the kit. The most difficult part of this process for most producers will be obtaining the blood sample. Cows must be at least 30 days pregnant and 90 days from calving for the test to work. Also, producers who have no experience taking a blood sample will need to schedule this test with their local veterinarian. Once the sample is obtained, the samples are packaged and sent to a laboratory for analysis. The cost for the test is $2.50-3.00 per cow. So the total cost per cow will be the cost of the kit, plus the test cost, plus the cost of mailing and any costs associated with obtaining the sample if you cannot do it yourself. Likely the cost per cow will be about $5 per cow for most producers.

The results are normally obtained with 2-3 days and the accuracy of the test is very high. If the test calls the cow open, then the producer is 99+% sure the cow is open. When the test determines a cow pregnant, you can be 93-95% sure they are pregnant. This test will not determine stage of pregnancy (i.e. 90 days versus 120 days).

A final piece of information to keep in mind is to sell cull cows early. The market for cows is usually good through September, and then the price goes south at a fairly rapid pace until it bottoms out in November. So, pull the bulls at the end of the breeding season, schedule to pregnancy check your cows about 45 days later, and get rid of the open cows and other culls before cow prices take a nose dive.

So PLEASE have pregnancy diagnosed in your cows. It will save you money.

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