Annual synchronization - fertility problems in beef cows

Producer Question from 2014

Q:  Can annual synchronization of females cause fertility problems in beef cows? (April 1, 2014)

A:  Synchronizing estrus in cows and heifers is an effective way to maximize the use of time and labor required to detect standing estrus in cattle. In addition, by using estrous synchronization more cows can potentially conceive and become pregnant early in the breeding season with no decrease in fertility.

Some estrous synchronization protocols can even induce estrous cycles and shorten the anestrous postpartum period allowing cows to conceive earlier in the breeding season. Because some estrous synchronization protocols can induce estrus in non-cycling beef females, this is not a replacement for good nutritional management practices. The females that are most likely to be induced to come into estrus are those that are already close to cycling.

However, when estrous synchronization is used together with artificial insemination, one of the largest factors that influence fertility is efficiency and accuracy of estrous detection.

When fertility is defined as the percentage of cows that conceive in the first few days of the breeding season, synchronized cows will have increased fertility compared to non-synchronized cows.

When fertility is defined as the percentage of cows that conceive during the first cycle (first 21 to 25 days) of the breeding season, estrous synchronized females will have similar or better fertility than non-synchronized females depending on the percent of animals that are anestrous or prepubertal and the synchronization protocol used.

Therefore, estrous synchronization can be a tremendous management tool to get more cows pregnant early in the breeding season.

Drugs used in these programs are naturally occurring in the animal.

Rick Rasby
Extension Beef Specialist
University of Nebraska-Lincoln