Heifer selection strategies: Does she stay or does she go? January 2025
Researcher Dr. Susan Markus, livestock research scientist, Lakeland College
Summary Dr. Susan Markus at Lakeland College Applied Research, along with her research team, investigated the use of genomics with phenotypes to better predict the success (longevity) of replacement beef heifers in the cow herd- especially past their second calving. The objective of this project was to identify which variables are associated with greater reproductive performance (higher number of pregnancies) so replacement heifer selection can be done at an earlier age/stage in the production cycle.
Background Fertility is the number one trait linked to profitability for cow-calf herds. It’s also of low heritability and sometimes difficult to assess depending on your record-keeping system. Typically, it includes age at first calving, pregnancy rate, calving interval and longevity or stayability. Unlike the feedlot sector that relies on highly heritable growth traits, cow-calf operations need to focus on fertility first, then growth and carcass traits. It is also well established that reproductive success in the first calving season is highly linked with a cow’s lifetime reproductive efficiency. So, in addition to good nutrition and health protocols, using commercial replacement heifer selection strategies that include evaluating conformation, body condition, weight, age, and adherence to breeding seasons of less than 45 days make the most sense.