Buller steer syndrome occurs when feedlot cattle repeatedly mount a single steer (the buller), causing injury, stress, and severe weight loss. In U.S commercial feedlots, this behavioral issue costs operators $300-800 per affected animal through direct injury, reduced daily gain, and pen-wide disruption. Early detection through systematic pen observation is the single most effective way to limit economic losses, as the condition escalates rapidly once mounting behavior begins.
The $12,000 Week One Kansas Feedlot Didn’t See Coming
Do you Know that, a $5000 head feedlot outside the Dodge city, Kansas discovered four buller steers in a single week last September. Let me tell you one incident, the operator walked with pens twice daily. and feed bunks were managed tightly. the water was clean and accessible. Everything looked normal until a pen rider noticed one steer standing alone while the rest of the pen ate breakfast. and by the time they pulled the steer, he had lost 40 pounds in just six days. and they noticed that tail head was raw and swollen. and they noticed that three other steers in different pens showed the same pattern within 72 hours.
Total Damage: It was roughly $3,200 in lost-gain and treatment costs across four animals, and the most frustrating part was each case started with not very noticeable signs that were easy to miss during the routine checks. and this is the challenge with Buller steer syndrome, we don’t see it until it’s already costing us the money. The mounting behavior happens when we’re not watching it. The targeted steer looks perfect from our truck until suddenly he doesn’t looks fine.
According to me, most feedlot losses from this condition are preventable if you know exactly what to look for and how fast to act. The difference between a $200 problem and an $800 disaster is usually 48 hours.
What’s Really Happening in Your pens
The Behavioral Trigger
Buller steer syndrome is not a disease. It’s a behavioral breakdown that starts with hormonal imbalance and increases through social stress.
I have studied that cattle establish social hierarchies through Visual, posturing, and occasional physical contact. In normal pen conditions, steers settle into a stable ranking within the days of arrival. and mounting behavior in feedlot cattle is typically rare and responding to nearby females. But when a steer hormonal signals gets disrupted, the other cattle in the pen notices him differently. his body language, behavior may trigger mounting responses from pen mates. and when steer mounts him, others follow it. this behavior becomes continues because the targeted animal’s stress response intensifies the problem.
The Biological mechanism involves the hypothalamic pituitary adrenal axis. This is not about the aggression. The other steers aren’t trying to hurt him. They’re responding to confused behavioral signals the buller steer is unintentionally sending. That’s why pulling the affected animal immediately breaks the cycle. Remove the target, and the mounting behavior stops.
Why It’s Hard to Catch Early
Most of the U.S feedlots run pen checks twice daily morning and evening. That’s the industry standard and generally sufficient for identifying sick cattle, checking water, and monitoring feed consumption. But…
According to me, most of the operators miss early-stage buller steer syndrome because the mounting activity happens between checks. A steer might get mounted six times between your 6 AM and 4 PM rounds. By the time we notice he’s standing alone or showing tail damage, he’s already been targeted for 24-48 hours. The early warning signs precise, like he is not Limping, not sick, and just seems slightly standing by himself, maybe at the back of bunk when all others are eating. In a 200-head pen, one quiet steer doesn’t immediately grab our attention.
Large commercial operations face additional challenges. When we’re checking the 40-50 pens in a morning, we are looking for the critical Points like downers, respiratory cases, obvious injuries. A steer standing alone might get a special note but not the immediate action unless you’ve been trained specifically on buller steer behavior patterns.
Weather Increases the problem. During the hot summer months in Texas or Oklahoma, cattle gather in shade. During the mud season in Iowa or Missouri, they crowd on the dry spots. Both the situations make individual animal observation harder. we need deliberate, systematic pen walks where we should be specifically watching for social isolation and mounting activity not just scanning for obvious problems.
5-Minute Pen Check: What to Look For
When we walk with pens, this is how we can quickly detect, this process works when we are checking 10 or 100 pens, and it catches buller steer syndrome in the early stages when the intervention is most effective.
1. Isolated animals Standing Alone while others feed or rest
This can be our first and most reliable flag. When one steer consistently positions himself away from the group especially during feeding, it signals social stress. He’s not sick enough to be down, but he’s uncomfortable enough to avoid the pen. What I have experienced is that isolation starts 12-24 hours before visible physical damage appears. If you see this, stop and watch that animal for 60 seconds. Is he nervous? Is he looking around constantly? That’s our cue to investigate further.
2. Mounting activity during Observation Period
In a normal feedlot conditions, we might see brief mounting behavior related or Closeness to females in adjacent pens, but it’s infrequent and doesn’t target the same animal repeatedly. If we witness mounting during our five-minute pen walk, assume it’s happening multiple times daily.
The biological reality is that mounting behavior follows a pattern and it peaks at certain times (morning and late afternoon) when cattle are most active. Catching it once means it’s already established.
3. Tail Head damage visible from normal Viewing distance
We need to look at the area directly above the tail and along the rump. we’re checking for hair loss, broken skin, swelling, or raw patches. This damage happens because mounted animals try to escape by moving forward, which creates friction and pressure on that specific area. By the time tail damage is obvious from your truck, the steer has likely been mounted 20-30 times minimum.
I have seen that severe cases show bruising that extends down the hind legs and across the hip bones. But we can catch it earlier by looking for the hair starting to thin or look wet from repeated contact before skin breaks.
4. Behavioral anxiety where the steer won’t settle
The animal can’t relax because he’s preparing for the next mounting event. His stress response is chronically elevated. During my practical exposure working with feedlot behavior, this anxiety sign gets misread as general nervousness or reaction to human presence. The difference is persistence an anxious buller steer acts this way even when you’re 50 yards away and not interacting with the pen.
5. Pen Social dynamics showing multiple cattle following one Animal
When a cattle move from the bunk to water or from resting areas to shade, do the several animals consistently approach or follow one particular steer? This targeting behavior indicates the pen has identified a buller.
Why This Keeps Happening in U.S Feedlots
Hormonal and Implant Factors
Let me tell you that growth-promoting implants are standard practice in American feedlot operations. These implants typically containing combinations of hormones like trenbolone acetate, estradiol, or progesterone, increase feed efficiency and daily gain by 15-25%. They’re safe, legal, and economically essential for commercial beef production. But the implant absorption varies by individual animal. Most steers metabolize the hormones consistently, maintaining the intended anabolic effect. A small percentage estimated at 1-3% of implanted cattle experience absorption issues where hormone levels don’t stabilize normally.
As per my knowledge, when the hormone metabolism is disrupted, a steer can exhibit behavioral signals that other cattle misinterpret. His pheromone profile changes. His physical manners shift slightly. To the pen mates, he may present cues similar to a female in estrus, even though he’s a castrated male.
This triggers the mounting behavior from other steers who are responding to what they perceive as reproductive opportunity. This is not an implant failure. The product works as designed in the vast majority of animals. It’s about individual physiological variation in how that steer’s body processes the exogenous hormones. we can’t predict which animals will have this response, which is why early detection through observation is more practical than trying to prevent it through implant selection.
Midwest feedlots uses the aggressive implant strategies to maximize gain on high-corn rations. Southern operations feeding in extreme heat may see interaction effects between the heat stress and hormone metabolism. High Plains feedlots with longer feeding periods (150+ days) see most cases occurring in the middle third of the feeding cycle when cattle are adapting to finishing rations.
Pen Environment and Density
Commercial U.S feedlots typically stock the pens at 125-200 square feet per head, depending on region, climate, and facility design. This density is economically necessary and generally appropriate for cattle welfare when pens are well-managed.
As per my studies, I can say that cattle need clear sight lines and escape routes to maintain social structure. In overcrowded pens or pens with poor layout (blind corners, narrow passages between bunk and water), subordinate animals get trapped in situations where they can’t avoid dominant pen mates. A steer being targeted for mounting has nowhere to go. He can’t establish the distance. The behavior strengths because spatial relief isn’t available. Pen surface conditions matter more than most operators realize.
Mud creates crowding because cattle naturally seek the driest spots, concentrating animals into smaller effective space. Dust in High Plains feedlots during summer causes cattle to bunch in specific areas with better air flow. Both conditions increases the contact frequency, which means more opportunity for mounting behavior to start.
Social Stress and Mixing
U.S feedlots source the cattle from diverse origins: auction barns, backgrounding operations, ranch-direct sales, and order buyers assembling loads from multiple sources. This means most feedlot pens contain cattle that didn’t grow up together and haven’t established stable social relationships.
According to me, buller steer syndrome risk peaks during this social adjustment phase, typically 30-90 days on feed. New arrivals are still figuring out pen dynamics. Some animals are more submissive by temperament. Others are bolder and more likely to initiate mounting if they perceive ambiguous signals from pen mates.
Weight variation within pens increases this issue. Industry recommendations suggest keeping cattle within 100 pounds of each other in the same pen, but practical realities are load sizes, facility capacity, timing of arrivals mean many pens have 150-200 pound spreads. Lighter animals are more vulnerable to targeting because they’re physically smaller and more easily dominated. Angus and Angus-cross cattle the dominant genetics in U.S. feedlots generally have calmer dispositions than continental European breeds, but individual variation is high. A pen with one or two particularly nervous animals can see buller steer syndrome develop simply because those animals’ stress responses trigger mounting from bolder pen mates.
Seasonal and Climate Patterns
Do you know that, Heat stress and buller steer syndrome are closely linked. When ambient temperatures exceed cattle’s thermoneutral zone (roughly 77°F for feedlot cattle), they experience metabolic stress that affects behavior, hormone regulation, and social interactions. During heat events that are common in Southern Plains feedlots from June through September the cattle bunch in limited shade, crowd water tanks, and spend more time standing rather than lying in hot pen surfaces. This increases the physical contact and social tension. Stress hormones like cortisol rise. Appetite decreases. All of these factors increase buller steer syndrome risk.
I have seen that the worst cases in Texas and Oklahoma feedlots occur during prolonged heat waves where nighttime temperatures don’t drop below 75°F. Cattle can’t recover from daytime heat stress. Chronic elevation of stress hormones disrupts the normal behavioral regulation that keeps mounting activity minimal.
As per my Knowledge, Peak Occurrence windows are:
- Southern States: Late June through August ( extreme Heat )
- Midwest Operations: April-may and October-November ( Weather Variability )
- High Plains: July-August ( heat ) and December-January ( Extreme Cold Stress )
Operations in the consistent climates see more stable patterns, while regions with high weather variability experience more unpredictable timing of cases.
Proven Management Steps to Cut Losses
Steps you can follow to Cut Losses
Step 1: Immediate Pen Separation Protocol
The moment we confirm a buller steer with visible tail damage, observed mounting, or clear social isolation with anxiety, remove that animal from the pen immediately. Don’t wait for the next processing day. Don’t watch him another 24 hours. Every hour he remains with the pen adds to physical damage and weight loss.
What I have experienced is that buller steers removed within 48 hours of first symptoms typically recover 70-80% of their lost performance potential. Animals that stay in the problem pen for a week or more rarely return to normal finishing performance. The stress effects are too severe and prolonged. This single management action immediate separation prevents $400-600 in additional loss per animal by stopping the cycle before chronic damage occurs.
Step 2: Pen Observation Schedule Adjustment
Standard twice-daily pen checks work well for general health monitoring but missing the specific timing when mounting behavior peaks. Buller steer syndrome activity concentrates in morning hours (6-10 AM) and late afternoon (4-7 PM) when cattle are most active and moving between bunk, water, and resting areas.
Step 3: Pen Environment Modification
Reduce the effective pen density during high-risk periods (weather extremes, diet transitions, new cattle arrivals) by temporarily splitting large pens or moving cattle to give more space. The target during heat stress should be 150-175 square feet per head rather than the normal 125-150. This gives animals enough room to maintain personal space and reduces forced contact at shade and water.
Step 4: Social Group Management
We need to minimize weight variation within the pens at arrival. The closer you can keep cattle to a 75-100 pound spread, the more stable social hierarchies will form and the less likely you are to see dominant animals targeting smaller pen mates. This requires better sorting at receiving or working with order buyers to assemble more uniform loads, but it reduces multiple management problems beyond just buller steer syndrome.
Step 5: Feed and Water Access Evaluation
Ensure adequate bunk space so cattle can eat without excessive competition. Industry standards suggest 22-26 inches of linear bunk space per head for finishing cattle. When bunk space is limited, subordinate animals wait for dominant pen mates to finish eating, which means they’re consuming feed when it’s been picked over and during hotter parts of the day. This affects gain and increases stress.
Step 6: Long term Prevention through Selection and Protocol Review
You need to work with your implant supplier and consulting veterinarian to review implant protocols if you’re seeing buller steer syndrome at rates above 1-2% of cattle on feed. While we can’t eliminate hormonal variation entirely, some implant products and timing strategies have lower association with behavioral issues in certain cattle types. This isn’t about abandoning growth promotants—it’s about optimizing protocols for your specific operation and cattle sources.
Real Cost Breakdown for Feedlot Operations
| Cost Factor | Per Head Loss |
| Weight loss(0.5-1.5lb/day * 20-40 days) | $140-320 |
| Injury treatment, Monitoring, Mortality risk | $80-280 |
| Pen Disruption | $40-100 |
| Labor for separation, special handling | $30-60 |
| Lost Oppurtunity | $50-150 |
| Total Average Loss | $340-910 |
1. How quickly can a Buller steer situation turn Serious ?
Very quickly, often within 48-72 hours. Mounting behavior can start finely, but once a steer is identified as a target by pen mates, the frequency accelerates rapidly
2. Can Buller steer syndrome spread to multiple animals in one Pen ?
Not in that way disease spreads, but you can see multiple cases in the same pen or in nearby pens during high-risk periods.
3. Do I need to change my entire feeding program ?
No. Buller steer syndrome is primarily a behavioral and management issue, not a nutritional problem.
4. When should I call my Veterinarian ?
Call your vet when a buller steer has severe physical trauma (deep wounds, infection signs, inability to stand), when the animal isn’t responding to separation and recovery management within 5-7 days, or when you’re seeing multiple cases across many pens and want professional input on whether implant protocols or other factors need review
Educational Purpose and Zoologist Perspective
Shaik Anas Ahmed, Zoologist (B.Sc. Botany, Zoology, Chemistry):
This article provides zoological and behavioral insights into buller steer syndrome based on animal science principles and practical feedlot observations.
Disclaimer
This content is for educational purposes and does not constitute veterinary medical advice, diagnosis, or treatment recommendations. Every feedlot operation has unique circumstances including climate, facilities, cattle sources, management systems, and regional factors that influence how behavioral problems develop and should be addressed.
Always consult a qualified, licensed veterinarian for medical decisions regarding your cattle. This includes diagnosis of injuries, treatment protocols, implant selection and administration, assessment of severe cases, and any situation where professional veterinary judgment is needed to protect animal welfare and ensure compliance with industry standards and regulations
The economic figures and loss estimates presented represent industry averages and typical cases. Your actual costs and outcomes will vary based on cattle prices, feed costs, facility design, labor availability, and management effectiveness. Use these figures as general guidance, not exact predictions for your operation.
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Livestock management involves inherent risks, including physical injury and financial loss. By using this website, you acknowledge that any management changes you implement on your ranch or feedlot are done at your own risk. livestockcure.com and its authors are not liable for
- ​Any injuries to persons or animals.
- ​Loss of livestock or decreased production.
- Financial damages resulting from the application of the strategies discussed here.
Every operation has unique circumstances. What works on one ranch may not work on another. Use your judgment, consult with professionals familiar with your operation, and prioritize safety in all livestock handling decisions.
