A lame breeding bull can affect more than a single animal’s health. During the breeding season, bulls are responsible for finding, courting and servicing cows across large pastures. If lameness reduces a bull’s willingness or ability to move, reproductive performance can suffer long before anyone realizes there is a problem.
Detecting lameness in pasture-based beef systems is not always straightforward. Unlike dairy cattle that are observed daily in parlors or handling facilities, breeding bulls may spend weeks in large grazing areas with limited direct observation. By the time a limp becomes obvious, the bull may have already been experiencing discomfort and altering his behavior for days.
New research from the University of Calgary suggests those behavioral changes begin before lameness is visible to observers and that remote monitoring technologies could eventually provide producers with an earlier warning system.
Can Technology Help Detect Lameness in Breeding Bulls?
Researchers monitored 25 Angus bulls over two breeding seasons in Alberta using collars equipped with GPS units and accelerometers. The devices continuously recorded movement and activity patterns while the bulls were on pasture.
At the same time, researchers conducted regular video observations and locomotion scoring to identify bulls that developed lameness during the breeding season. Their goal was to determine whether behavioral changes could be detected before lameness became apparent through visual observation.
Across the study, 10 lameness events were analyzed. When researchers compared affected bulls with their own historical behavior and with healthy herdmates, a clear pattern emerged: Bulls that became lame started moving differently before lameness was officially identified.
Early Signs of Lameness in Breeding Bulls
The strongest signals came from measures of movement.
Before lameness was detected through routine observation, researchers found:
- Walking time declined up to three days before detection.
- Distance traveled dropped by about one kilometer two days before detection.
- Average velocity decreased in the days leading up to diagnosis.
- Home range size shrank as bulls used less of their available pasture.
These changes were observed when affected bulls were compared both with healthy herdmates and with their own historical baseline behavior. This suggests the differences were not simply the result of weather, pasture conditions or normal day-to-day variation.
Researchers also evaluated activity, grazing, resting, rumination and fighting behavior. While some shifts were detected, including increased rumination and reduced fighting, those measures were less consistent than the movement-related metrics. Grazing and resting behavior showed little value as early warning indicators.
The results point to a clear pattern: Bulls that later became lame did not dramatically change how they spent their day, but they did change how they moved through their environment. That consistency across both accelerometer and GPS measurements suggests reduced mobility may offer the greatest potential for early lameness detection in breeding bulls.
Early Lameness Detection is Important for Breeding Bulls
Lameness is one of the most common health challenges affecting breeding bulls and can directly influence reproductive performance.
Previous research has shown lameness is associated with a higher likelihood of failing a breeding soundness evaluation and can impair a bull’s ability to travel, locate and mount cows during the breeding season. In multi-sire systems, a lame dominant bull may continue interfering with subordinate bulls while breeding less effectively himself.
Earlier detection could create opportunities for faster intervention, earlier treatment and more informed replacement decisions during the breeding season. In situations where breeding opportunities are limited, even a few days could make a meaningful difference.
Could Wearable Sensors Improve Bull Health Monitoring?
This is the first study to evaluate remote monitoring technologies for early lameness detection specifically in breeding beef bulls on pasture. This work provides evidence that wearable technologies can identify meaningful behavioral changes before lameness is recognized visually.
As precision livestock farming tools continue to expand into beef production systems, movement-based metrics such as walking time, distance traveled and velocity may become valuable components of automated health-monitoring programs.
The technology may still be evolving, but the biological message is already clear: Breeding bulls do not suddenly become lame. Their movement patterns begin to change before lameness becomes visible, creating an opportunity for earlier intervention and potentially better reproductive outcomes.
