Effective maintenance improves animal well-being. Nowhere is this more evident than in the stunning area of the plant. Let’s consider how to improve animal welfare through effective maintenance of the captive bolt stunner.

Small But Mighty
Simply put, captive bolt stunners must operate effectively every time. Though small, these critical pieces of equipment can have a mighty impact on humane slaughter and the downstream operation of the plant. Astute attention to detail is required to properly maintain and operate the stunning equipment.


In a 2009 presentation at the AMI Animal Care and Handling Conference, presenter Chuck Bildstein of Bunzl Inc. called captive bolt stunners “the most important equipment in the beef plant”. They are important enough that their effectiveness is required as a matter of public law. The Humane Slaughter Act of 1978 mandates: “all animals are rendered insensible to pain by a single blow ..., before being shackled, hoisted, thrown, cast, or cut.”

Poor Stunning Can Be Egregious
FSIS Notice 14-08, which covers humane handling activities in slaughter plants, specifies 10 egregious acts of inhumane handling. ”Egregious” is defined as “outstandingly bad, or conspicuously offensive”. In the context of humane handling, egregious acts call for a strong regulatory response from FSIS.

Four of the 10 egregious acts described in Notice 14-08 are related to ineffective stunning, which can result in a failure to achieve or sustain insensibility. A number of plant suspensions have resulted from failures to properly maintain the stunning equipment.

With so much at stake, it is vital that plants have a sound stunner maintenance program. By following a few basic guidelines it is possible to achieve a high level of humane stunning effectiveness.

Achieving a “ Stunning Difference”
Excellence in stunning is attainable by every plant. It requires setting high-performance expectations and planning for success. The following are a few key attributes to a successful maintenance program for captive bolt stunners

1) Clean and maintain daily. This basic step ensures the stunner is examined each day for wear, buildup, and the operating effectiveness of the components of the stunner. There are still cases where stunning equipment is put away at the end of one day and returned to service the next day without being examined. This is risk taking that will eventually result in poor stunning performance and negative consequences.

2) Preventative maintenance guidelines. The manufacturer provides an equipment manual for each type of stunner for daily, weekly and monthly PMs. These are the “Bibles” for stunner use, and should be readily available for both operators and mechanics.

3) Measure the performance of the stunner by using a test stand prior to the start of each production day. This verifies the equipment is operating effectively prior to use. Ignoring this step can allow an improperly operating stunner to be put into service. Some Humane Handling NRs (Noncompliance Reports) and plant shutdowns have resulted from start-of-the-day failure of equipment that wasn’t tested.

4) Have backup stunners available. This provides the ability to switch equipment anytime a variance in performance is detected. For pneumatic stunners, there should be 100 percent backup for air compressors and filters as well. In some cases, egregious acts have been identified because the backup stunners were not tested, resulting in a poor stun followed by another poor stun.

5) Keep a service log for each stunner. We manage what we measure, so record daily cleaning and repair activities and results of pre- shift stun testing . This will help identify patterns and troubleshoot problem areas and equipment

6) Training for mechanics and operators is an essential part of a successful process. Most equipment manufacturers provide in-plant training for their equipment. Periodic refresher training is beneficial to correct knowledge drift that happens over time.

7) Teamwork! Share knowledge about how the stunning equipment performs. Some plants post the stunning scores hourly as they are audited. This lets mechanics and operators see how the equipment is performing. Entrusting the details to the team engages the members and creates ownership around stunning performance.

Many plants have both pneumatic and cartridge fired stunners in their cadre of tools. Each type has its own unique attributes, which need to be accounted for. This includes such items as proper maintenance of the oiler on the pneumatic stunner, and the dry storage of cartridges for the cartridge fired stunner. Ensure that your program gives equal attention to each type.

Rely on the Pros
Manufacturers of the captive bolt stunners are a valuable resource for stunner maintenance. Their equipment is designed and sold on its capabilities for humane stunning, and they are eager to help plants achieve the equipment’s full potential.

Greg Hanson, service manager for Middletown, Conn.-based Jarvis Products Corporation, says it is hard to pick out just one or two items that will ensure near perfect stunner performance. “It’s all important,” he says. “It’s hard to say that one thing stands out above the others, because each plant is different. Each plant has different people with different skills. So when a plant has a problem, they tend to be different problems.” Issues vary by location and application, says Hanson, emphasizing the importance of the manufacturer’s written recommendations. “To be successful, you have to pay attention to everything in the product manual. It’s all spelled out in there.”

In addition to daily cleaning and maintenance, Chuck Bildstein of Bunzl stresses the people component of stunner maintenance: “It’s important to have properly trained maintenance people and operators.” He added, “Some plants limit the number of mechanics and operators who handle the equipment and require them to be certified for performing those tasks. This creates a sense of pride and ownership in their work.”

It Takes a Team
Both Bildstein and Hanson agree that it’s beneficial to have an open dialogue between mechanics and operators, where each know the other’s functions, and working together to keep the stunning equipment performing properly.

Good stunning performance is attainable only when it is built on a foundation of good stunner maintenance. When there is a team and process around this critical equipment, “stunning” results will be achieved.

With a background of working in various production roles for 30 years, from floor cleaner to plant general manager, Jerry is the owner of Karczewski Consulting (www.diversecattle.com) providing humane handling and plant operations services, with a focus on cull dairy cattle. Contact Jerry by e-mail at [email protected], or at 262-490-8293.