2001 Restaurant Audits of Stunning and Handling in Federally Inspected Beef and Pork Slaughter Plants

2002 American Meat Institute Animal Handling and Stunning Conference

Temple Grandin Department of Animal Sciences Colorado State University Fort Collins CO 80523

Summary for Beef Plants

Stunning was scored in 44 beef plants in 17 different states. The audits were conducted by four different auditing systems: McDonalds, HACCP Team, Wendy’s HACCP team, a commercial third party auditing company and T. Grandin. Scores were averaged for plants that received more than one audit. Ninety-one percent of the plants passed the stunning audit which required 95% in more of the cattle to be effectively stunned with one shot (Table 1). When the data was summarized by three separate audit systems, the percentage of plants that passed the stunning audit were 88%, 86%, and 89% (Table 2). The stunning data illustrates the need for constant vigilance and auditing to maintain high stunning standards. Two plants (5%) had very low scores of 88% and 82% due to a lack of stunner maintenance and poor management supervision. The majority of plants have maintained good standards. Management who is committed to welfare is the key.

Cattle Vocalization (Moos and Bellows)

Compared to 1999 and 2000 audits the percentage of plants that passed the vocalization audit with 3% or less of the cattle vocalizing has improved. Eighty-six percent of the plants passed (Table 3). There were 5 plants that had a not acceptable rating with 4% to 10% of the cattle vocalizing. Two of the plants had 7% of the cattle vocalizing due to balking and electric prod use. Three had slightly elevated vocalization scores of 4% or 5%. These plants had no obvious problems. One plant had a serious problem with 20% of the cattle vocalizing. This plant also had a 100% electric prod score and a stunning score below 90%. They had a complete lack of management supervision.

Comparison Between Different Auditors and Auditing Systems

From a statistical standpoint there is absolutely no difference between the stunning pass rates of the three auditing systems (Table 2). A chi square test between the highest and lowest scores was .077 P = <.75 which does not even approach statistical significance. Table 4 shows data from three different auditors who audited the same three plants. The audits were conducted on different days with no collaboration between auditors. The data provides preliminary indications that three different auditors did not have widely different results. All these plants have been audited dring the last 2 years and they all have a well established internal system of self audits. Nine plants that were audited by two different auditors from different auditing systems also had similar scores (Table 4B).

Electric Prod Use

Electric prod use scores for the excellent and acceptable range were similar to year 2000. Unfortunately 16% of the plants used an electric prod as their primary driving tool on most of the cattle .One plant had no electric prod use, but whips were used in an abusive manner and cattle were repeatedly hit in the eye (Table 5). The employees were poorly trained and they overloaded the crowd pen.

Cattle Insensibility

When all the audits by the four different auditing systems were combined there were 7551 cattle observed during 2001. Four plants had 11 cattle showing signs of partial sensibility. This is within the acceptable range in the American Meat Institute guidelines. Stunning bulls with heavy skulls was the main problem. Bull stunning needs improvement. In one plant a partial return to sensibility occurred during an official restaurant audit and in three other plants they occurred during unofficial visits for auditor training. Training visits were announced and the plant knew they would not be officially audited. The animals were restunned prior to the start of slaughter procedures. In the first plant the cause of the partial insensibility was not written down. In the second plant a poorly maintained stunner with a damp cartridge failed to properly stun bulls and cows. In the third plant partially sensible animals were caused by an inexperienced stunner operator. In the fourth plant, bulls were not rendered completely insensible. The use of a test stand for checking bolt velocity is strongly recommended. This is especially important for stunning bulls.

Effects of Equipment Improvements and Observation Methods

Table 6 shows how simple improvements in a cattle stunning box improved stunning, vocalization and electric prod scores. The method of observation significantly affects electric prod use. An electric prod was used on significantly more cattle when the audit was done on a closed circuit video camera. An electric prod was used on only 10% of the cattle when the driver could see the auditor and on 25% when the drive did not know he was being observed (Table 7).

Downer and Non-Ambulatory Cattle

The handling of non-ambulatory cattle is a problem area. In one plant a non-ambulatory animal was dragged prior to stunning. In other plants increased USDA enforcement of Humane Slaughter Act regulations may be driving downer problems underground. At one plant, non-ambulatory cattle that were loaded onto the truck at the feedlot were dropped off at a local locker plant before the truck came to the USDA inspected establishment. The author has recently observed increasing problems with broken legs in fed feedlot cattle. Fine boned heifers may be more likely to break a foreleg when they jump. Genetic changes in cattle breeding may be contributing to the problem.

Problem Areas for Cattle

Table 8 summarizes some specific problems that were observed in seven beef plants. During the last two years many of the facility problems which would cause a plant to fail an audit have been fixed. See the 2000 and 1999 results for more information. One major equipment problem that remains is stunning heavy bulls with one shot. To stun bulls effectively plants may need to keep a special bull stunner that should be replaced when it becomes slightly worn and loses hitting power. The majority of remaining problems areas are centered around either poor maintenance of stunning equipment or poor management supervision. Handling of non-ambulatory cattle is another problem area. Plants that have strong internal auditing systems and good employee training programs are able to maintain high standards. Constant vigilance by customer auditors will be required to maintain adequate standards in a few plants that have poor management. In the future, customer auditors should examine the handling of non-ambulatory animals more closely. Two plants (5%) had significant declines in their audit scores due to a lack of management or change in management. In the first problem plant the stunning score was 88%, prod score 100% and vocalization was 20%. In the second problem plant two audits early in the year had excellent scores of 99 and 90% for stunning. A third audit later in the year indicated that their score dropped to 86% due to a lack of stunner maintenance and employee training. Poor management was the cause of the problem in both of these plants.

Summary for Pork Plants


Twenty federally inspected pork slaughter plants were audited in either different states. The audits were conducted by 3 different auditing systems: McDonalds HACCP team, Wendy’s HACCP team and T. Grandin. Scores were averaged for plants that received more than one audit. Electric stunning was assessed in seventeen plants and three had CO2 stunning. Eighty-eight percent of the plants that used electric stunning placed the stunning wand in the correct location on the pig’s head (Table 9). This is similar to last year’s results. Eighty percent of the plants energized the wand correctly so that 100% to 99% of the pigs remained quiet when the stunning wand was applied (Table 10). Two plants (12%) out of 15 plants failed the electric stunning audit when the scores for placement and “hot wanding” were combined. The three plants that used CO2 rendered all pigs insensible on the bleed rail.


Two plants out of 20 plants (10%) failed an initial annual audit for having pigs showing signs of partial return to sensibility on the bleed rail. Both plants used electric stunning and re-audits indicated that the problems were corrected. The insensibility problem may be related to wand design. Three years of audit data are indicating that some wand designs work better than others.

A total of 2750 electrically stunned pigs were observed during 2001 (Table 11). Two pigs showing partial return to sensibility were observed. Therefore there was one partially sensible pig per 1375 pigs. The industry needs to improve electric stunning. The number of partially sensible pigs is still within the minimum standard in the American Meat Institute standards. All pigs were rendered insensible before they reached the scald tub. There must be a zero tolerance for signs of sensibility at the scald tub. Changes in wand design at several plants that have had chronic problems will probably greatly reduce the incidence of partial return to sensibility. All CO2 pigs were rendered insensible on the bleed rail.

Comparison of Different Auditors and Systems

Due to the smaller number of pork plants, there was insufficient data to compare the different auditing systems. Table 12 shows comparisons of stunner placement scores between two different auditors that are from different auditing systems. There is a high degree of agreement between auditors. The pig return to sensibility problems observed in two plants were detected by an audit from one of the auditing systems and corrected before an auditor from a second system visited.

Squeal Scoring

Squeal scoring comparisons between plants have become increasingly difficult because more plants are installing two restrainers or two CO2 machines in the same room. Doing this has improved animal handling but makes squeal comparisons between plants more difficult. Plants are strongly encouraged to monitor squealing within their own facility as a method of improving the quality of handling. At one plant that used electric prods very sparingly on 10% or less of the pigs, an easy to drive group squealed 20% of the time and a group of difficult to drive pigs squealed 85% of the time (Table 13). Continuous pig squealing is a sign of either rough handling and excessive use of electric prods or difficult to drive pigs. One pork plant out of 20 had pigs that squealed 100% of the time because electric prods were used to force pigs to jump on top of each other. Vocalizations of cattle are easy to score because individual animals can be easily identified. Squealing of individual pigs in the restrainer is useful for detecting equipment problems such as one side of the restrainer moving faster than the other.

Electric Prod Use

Compared to last year, the use of electric prods has increased (Table 14). Fifty percent of the plants scored in the excellent and good range in 2001 and 68% were in this range in the year 2000. The percentage of plants in the not acceptable range of 26% to 49% electric prodded has risen from 5% of the plants to 25%. At one plant electric prod use had to be increased 10% to move difficult to drive pigs. The author observed one load of heavy weight market pigs which were impossible to get off a truck without an electric prod.

Downers and Non-Ambulatory Pigs

The indiscriminant use of Paylean (Ractopamine) has contributed to an increase in downer non-ambulatory pigs. Some of these pigs are extremely difficult to move and drive. Reducing the dosage of Paylean will prevent handling and downer problems. Paylean is a feed additive that came into widespread use in 2001.

Problem Areas

Most problems with electrical stunning can possibly be fixed by changing the wand design to prevent it from slipping out of place. Some plants have excellent wands that do not slip and all of these plants rendered all pigs insensible.

The other big problem area is downers and handling problems caused by the indiscriminant use and over dosage of Paylean.

One plant had a CO2 machine and the line speed far exceeded the capacity of the machine. To keep up, too many pigs were forced into the gondola. An electric prod was used to force pigs to jump on top of each other. Fortunately this system now has two machines that are not overloaded. When a CO2 gondola is loaded there must be enough space so that the pigs can stand or lie down without being on top on each other.

Conclusions for Both Cattle and Pigs

Overall the year 2001 had similar performance compared to 1999 and 2000 for both cattle and pigs. To maintain adequate welfare standards for both cattle and pigs will require constant vigilance. Auditing by both plant customers and internal plant audits will be required on a continuous basis. The vast majority of beef plants maintained high standards but several plants had serious management problems and allowed their standards to deteriorate.

In beef the main problem areas were caused by either poor management or problems with stunning bulls. Whereas in pork, stunning equipment problems and hard to drive pigs were the major concerns. Plant management needs to work with pork producers to produce pigs that are easier to handle. Comparison of scores from different auditors and different auditing systems shows that there are consistent results between different observers.

Table 1. Captive bolt stunning in 44 beef plants in the U.S. Combined audit scores from four different auditing systems. Audit scores were averaged in plants that had more than one audit.
Percentage of Cattle Stunned with one Shot Number of plants Percentage of Plants 2001 Line Speed Range
Excellent – 99 to 100% 16 36% 11 To 390/hr
Acceptable – 98 to 95% 24 55% 50 to 390/hr
Not Acceptable – 94 to 90% 2 4.5% 175 to 200/hr
Serious Problem – Less than 90% 2 4.5% 40 to 70

Eighteen plants (40%) were audited more than once.
Causes for not acceptable and serious problem scores:
Plant 1. Not acceptable – Stunner maintenance
Plant 2. No acceptable – Stunning bulls
Plant 3. Serious Problem – Total lack of management supervision
Plant 4. Serious Problem – Stunning bulls

Table 2. Comparison between three different audit systems on the percentage of beef plants that passed the stunning audit with 95% or more of the cattle rendered insensible with one shot. First audit counted – Re-audits for failing not counted.
Audit or System Pass – Percentage of Plants Not Acceptable or Serious Problems – Percentage of plants Range of Passing Scores Range of Failing Scores
1 89% 11% 95 to 100% 88 to 92%
2 88% 12% 95 to 100% 82 to 92%
3 86% 14% 95 to 100% 93 to 94%
Average 3 Audit Systems 88% 12% Range – 94 to 82%
No statistical significance between audit systems Chi Square .077 P<0.75

Each system, audited a minimum of 20 different plants
Some plants were audited more than once by different systems.
Others were audited only once. There was a total of 44 different plants. For confidentiality reasons the number of plants in each group cannot be given, but it is 20 or more per system.

Table 3. Percentage of cattle vocalizing in beef plants in the U.S. Combined audit scores from four different auditing systems. Scores were averaged in plants with more than one audit.
Number of Plants 2001 Percentage of Plants Line Speed Range
Excellent 0 to 1% 18 41% 390/hr
Acceptable 2 to 3% 20 45% 11 to 390/hr
Not Acceptable 4 to 10% 5 12% 100 to 330/hr
Serious Problem over 10% 1 2% 70/hr
The plant with the serious problem had a 20% vocalization score, 100% electric prod score and 88% stunning score. Management in the stunning area was non-existent. Compared to 1999 and 2000, vocalization scores have improved. In 2001, 86% of the plants had either excellent or acceptable scores.

Table 4A. Comparison of stunning and vocalization scores between three different individual auditors. At three different fed beef plants, audits done independently on different days by auditors from different auditing systems.
Percentage of cattle stunned with one shot Percentage of cattle vocalizing
Auditor Plant 1 Plant 2 Plant 3 Plant 1 Plant 2 Plant 3
Auditor 1 100% 98% 98% 0% 4% 2%
Auditor 2 99% 100% 98% 0% 4% 2%
Auditor 3 99% 100% 100% 1% 0% 1%

A minimum of 100 fed feedlot cattle were score in each plant. The three plants on this table were the only plants that were audited by three different auditors from different auditing systems during the year 2001. All three of these plants have been audited during the past two years and have an active internal welfare auditing program. The three plants are three different companies. This data provides a preliminary indication that 3 different auditors had similar results.

Table 4B. Comparison of cattle stunning and vocalization scores taken by two different auditors from different auditing systems. Re-audits by the same auditing system are not included.
Plant Auditor No. 1 Auditor No. 2
Stunning Score Vocalization Score Stunning Score Vocalization Score
1 98% 4% 97% 5.5%
2 98% 0% 95% 0%
3 92% 0% 99% 2%
4 98% 2% 100% 0%
5 95% 0% 97% 0%
6 97% 5% 100% 1%
7 100% 2% 98% 0%
8 98% 2% 98% 2%
9 99% 0% 93% 2%
10 98% 2% 86% 2%

Plant 3 improved their stunning score when auditor 2 came at a later date. Plant 9 had an inexperienced stunner operator when the second auditor visited. The operator was a foreman and not the regular operator. The vocalization scores for plant 1 are slightly elevated due to balking at the restrainer entrance because it did not have a false floor. The false floor which prevents the cattle from seeing a steep drop off under the restrainer was missing during both audits. Plant 10 had allowed its standards to slip. When the second auditor visited later in the year, the stunning score had dropped due to poor maintenance and a lack of employee training. Changes in management may have contributed to the decline in standards.

Table 5. Electric prod use in 382 beef plants. Scores were averaged in plants that were audited more than once.
Percent of Cattle Electric Prodded Number of Plants Percent of Plants
0% - Excellent 91 24%
5% or less – Excellent 8 21%
6 to 25% - Acceptable 12 31%
26% to 50% - Not Acceptable 3 8%
Over 50% - Serious Problem 6 16%

1 One plant with 0% electric prod use had very abusive use of whips and cattle were repeatedly hit in the eye. The people in this plant lacked training. The crowd pen was stuffed full and the people constantly yelled.
2 Missing data due to auditors using imprecise estimates such as “occasional use” or “minimal use.”

Table 6. Improvements in stunning, vocalization and electric prod use scores after changes were made in a cattle stun box.
Percentage stunned with one shot Percent insensible Percentages of cattle vocalizing Percent electric prodded
Before Changes 93% 100% 4% 31%
After Changes 97% 100% 1% 7%

The changes were:

  1. Better handler training.
  2. New concrete nonslip floor in stun box.
  3. Light on stun box entrance.
  4. Rubber stops to prevent gate banging.
  5. Cut a small 1 in. x 6 in. (2.5 cm x 15 cm) hole at eye level in the solid stun box entry door to promote following behavior into the box.

All cattle in this plant were rendered completely insensible before being hung on the bleed rail.

Table 7. Comparison of electric prod use scores when the handler can see an auditor versus collection of data with a closed circuit video camera.
Percentage of cattle electric prodded
Auditor Present 10%
Video Camera 25%

Electric prodding is reduced when people know they are being watched. The same auditor collected this data on the same day.

Table 8. Seven beef plants that had serious problems – 16% of the beef plants.
Problem Comments
Plant 1 Complete failure of a restaurant audit with a 88% stunning score – 20% vocalization and 100% electric prod score. Total lack of management commitment to welfare
Plant 2 Slick floor caused cows to fall down and break their pelvis during truck unloading. Need to install a metal floor grating in unloading area.
Plant 3 Covered up downer problems by loading downers with a loader at the feedlot and dropping them off at a local locker plant before delivering the rest of the cattle to their own plants. Feedlot cattle that are unable to walk onto a truck must be euthanized at the feedyard.
Plant 4 Whipping cattle in the eye with whips Auditor Training Visit – No electric prods. Poorly trained employees
Plant 5 Sensible bull on the bleedrail with full righting reflex – immediately restunned. Auditor Training Visit – Bent firing pin damp cartridges.
Plant 6 Two cattle showing signs of sensibility on the bleedrail (spontaneous natural blinking) Auditor Training Visit – Inexperienced stunner operator.
All training audits were announced and the plant manager knew that the scores would not count as a real audit
Plant 7 Audit scores declined from 99% and 98% early in the year to 86% later in the year. The electric prod score increased from 25% to 55% Low stunning score caused by poor maintenance and training. A change in management may have been a factor.

Table 9. Electric stunner wand placement in 17 pork slaughter plans for passage of current through the brain. Data from three different auditing systems. Scores were averaged for plants that had more than one audit.
Percentage of pigs with correct wand placement Number of plants Percentage of plants Line speed per operator range
99% to 100% placement - Excellent 8 47% 480 to 1158/hr
99% correct - Acceptable 7 41% 600 to 1050/hr
98% to 95% - Not Acceptable 2 12% 150 to 980/hr

Several plants now have two stunner operators on one restrainer to prevent overloaded operator problems.
In plants with 2 operators, 50 pigs per operator were scored.
In plants with two restrainers, scores from both restrainers were averaged.
A total of 100 pigs were scored per audit.

Table 10. Electric stunner “hot wanding” where the wand is energized before it fully contacts the pigs. Scored yes if pig squeals when the wand is applied.
Percentage of pigs hot wanded Number of plants Percentage of plants Line speed per operator range
0% hot wanding – Excellent 9 60% 410 to 1158/hr
1% hot wanded - Acceptable 3 20% 480 to 1050/hr
2 to 3% - Not acceptable 2 13% 960 to 980/hr
4% or more – Serious Problem 1 7% 150/hr

Hot wanding data was not collected at 2 plants.

Table 11. Summary of plants with return to sensibility problems in 2001.
Species Reason
Plant 1 3 bulls and 2 cows partial sensibility Damp cartridges and bent firing pin on stunner
Plant 2 2 Cattle – partial sensibility (fed beef) Inexperienced operator
Plant 3 1 cow Not recorded
Plant 4 3 bulls Damp cartridges and poor stunner maintenance
Plant 5 One steer questionable Heavy skull, large horns
Plant 6 Market pigs – partial sensibility Wand design? Wand slipped onto the jowl
Plant 7 Market pigs – partial sensibility Wand design? Contact area too small. Slipping and very small bleed opening
Recommendation – Plants 6 and 7 may need to change their stunning wand design. The type of wand used slips out of position more easily compared to other wand designs

Table 12. Comparison of stunning wand position. Scores at seven pork plants that were scored by two different individual auditors. The audits were done independently on different days.
Plant Auditor/Percent Correct Auditor – 2 Percent Correct
1 100% 100%
2 99% 99%
3 99% 100%
4 99% 100%
5 100% 97%
6 100% 99.5*%
7 100% 100%

One hundred pigs were scored per plant.

* Scored 200 pigs instead of the usual 100 pigs.

Table 13. Electric prod use in 20 pork slaughter plants. Scores were averaged in plants that had more than one audit.
% pigs electric prodded Number of plants Percent Plants Comments
0% Excellent 1 5% Group handling CO2 had no single file race. State of the art system, some overcrowding with power gate.
1 to 15% - Good 9 45%
16% to 25% - Acceptable 4 20%
26% to 49% - Not Acceptable 5 25% Difficult to drive pigs
50% or more – Serious Problem 1 5% 100% prodded to force too many pigs into an overloaded gondola. Line speed exceeded the capacity of one CO2 machine.

Table 14. Comparison of electric prod use and squealing between a group of easy to drive pigs and a group of hard to drive pigs.
Percent Electric Prodded Percentage of Time that the Pigs Squealed
Easy to drive pigs 4% 20%
Hard to drive pigs 10% 85%

The plant had one restrainer so the percentage of squealing time could be easily estimated by counting the number of electric stunning cycles the pigs were silent. Electric prods were only used on pigs that backed up or balked. One hundred pigs were scored per group.

Table 15. Differences in the percentage of pigs prodded with an electric prod due to different conditions in two different restrainers in the same plant.
Restrainer Percent of Pigs Electric Prodded Reason
1 38% Dark entrance – Loose metal flap on the restrainer hold own.
2 4% Well lighted entrance

The handler only used the electric prod on pigs that balked or backed up.

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