Simply determining the percentage of the herd that became pregnant during the breeding season does not fully utilize all the numbers that can be generated during a typical pregnancy check. 

The Beef Cattle Institute (BCI) at Kansas State University (K-State) has created the Pregnancy Analytics app that will allow easy chuteside data collection at the time of pregnancy diagnosis. The app will immediately turn preg-check data into easy-to-read charts and tables that provide enhanced information for veterinarians, providing in-depth interpretation of the recently completed breeding season. 

An important limitation to the number of cows that can become pregnant each 21-day cycle is that there is only a 60-70% likelihood of a cow becoming pregnant and maintaining the pregnancy each time she ovulates a fertile egg and is mated by one or more fertile bulls. A fertile cow that ovulates and is mated but either fails to become pregnant or fails to maintain the pregnancy should express another fertile heat about 21 days after the last estrus — giving her another 60% to 70% likelihood of becoming pregnant. 

Because of the limitations associated with cattle reproduction, the best pregnancy pattern that can be reasonably expected is one where 60-65% of the herd becomes pregnant during the first 21 days of breeding. This level of reproductive success would provide evidence that nearly all the cows had resumed fertile cycles early in the breeding season and the bulls were fertile and successfully mating. 

If the nonpregnant cows continued to have fertile cycles and the bulls continued to successfully mate cows in heat, then 65% of the cows that failed to establish or maintain a pregnancy from the first cycle should become pregnant during the second 21 days of breeding. 

As the breeding season moves into the third 21 days, then 65% of the cows that failed to maintain a pregnancy from the first two cycles should become pregnant during the third 21 days of breeding. Therefore, after three cycles (or 60 to 65 days), the highest reproductive success that can be reasonable expected is for approximately 95% of the cows to be pregnant, with nearly 2/3 becoming pregnant in the first 21 days. 

Veterinarians know being able to visualize the percentage of a cow herd that became pregnant each 21 days of the breeding season can provide important information to identify the contributing causes for a lower than desired breed-up by identifying periods of time when breeding success was decreased. In addition, by evaluating the breeding season success for cows grouped by age, body condition or other description, the veterinarian can identify not only “when” breeding was less successful, but which types of cows were less successful. 

After entering preg-check data, the Pregnancy Analytics App automatically creates several very helpful graphs that show what percentage of the herd became pregnant each 21-day period of the breeding season, as well as the percent of the cows within each body condition and age category that became pregnant each 21-day period. 

Combined with information about the timing of births in the calving season preceding the breeding season, bull breeding soundness examinations, environmental and forage conditions, and management during the breeding season, the graphs and tables generated by the Pregnancy Analytics app are a powerful diagnostic tool to assist veterinarians and producers in improving the reproductive efficiency of beef herds.  

For more on the Pregnancy Analytics app from K-State visit www.ksubci.org/pregnancy-analytics-mobile-app/.

Editor’s note: Robert L. Larson is a professor of production medicine and executive director of Veterinary Medicine Continuing Education at Kansas State University in Manhattan, Kan.