Preg Check Your Cows . . . Please!

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

Well, it’s that time of year for me to plead with our producers to pregnancy diagnose their cows. This year appears to be even more important than the last few. The University of Kentucky has about 2500 cows on various Applied Master Cattleman projects throughout the state. Many of these farms have participated in these projects for two years. Cows in all of these projects are subjected to estrus synchronization prior to either natural service or to AI. These projects are designed to either demonstrate to producers how to shorten the calving season or the production and economic efficiencies of AI. Most of these cows have been diagnosed for pregnancy and, if these farms are any indication, pregnancy rates will be unexpectedly low this year. The last couple of years, these farms have averaged 59% AI and 91% overall pregnancy rate after a 60-day breeding season. This year, our AI rate is only 51% and the average pregnancy rate is only 79.5%!

Why are the pregnancy rates so low? Great question. Our best guess is that, after two straight years of drought, the cows entered calving in a lower body condition and our hay quality from last summer was well below average. This nutrient challenge likely delayed many cows ability to recycle after calving even though they were subjected to protocols to induce estrus in anestrous cows. These cows likely did not start cycling until July when fertility is typically low. If you do the math, half the herd conceived on one day and only half of the remaining cows conceived to the bull. I am tempted to blame the bulls but I have observed lower reproductive rates on numerous farms scattered across the entire state of Kentucky. Actually, I have observed normal reproductive rates in only 2 farms total this spring.

I hope “preg checking” is an annual ritual for your herd. 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 that requires an experienced veterinarian. Two practical methods for pregnancy diagnosis can be used in beef cattle: 1) rectal palpation and 2) transrectal ultrasonography. 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.

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.