2000 McDonald’s Audits of Stunning

and Handling in Federally Inspected Beef and Pork Plants

 

Temple Grandin

Department of Animal Sciences

Colorado State University

Fort Collins CO  80523

 

Summary for Beef Plants

 

         Stunning of beef cattle has continued to improve compared to the USDA survey done in 1996 and last year’s 1999 McDonald’s audits. Stunning was scored in 49 Federally inspected beef plants in 12 different states. The plants were evaluated with the scoring system in the American Meat Institute guidelines, by the McDonald’s HACCP team.  Forty-one percent of the plants stunned 99% to 100% of the cattle correctly with one shot and 90% performed at the 95% level or better on first shot stunning efficacy (Table 1). The average first shot stunning efficacy percentage for all plants was 97.87%. Four plants (8%) had not acceptable  first shot efficacy percentages of 94% and one plant (2%) failed with a score of 87%. In 1999, four plants (10%) had either not acceptable or failing scores. In the second half of 2000, unannounced audits were started. A comparison of cattle stunning scores indicated that significantly more plants in the announced group had excellent scores of 100% to 99% first shot efficacy (P = > .05) (Table 2). However, the difference between announced and unannounced audits was much smaller than the huge improvement in stunning which occurred when the McDonald’s audits started in 1999. A USDA survey in 1996 indicated that only 30% of the plants were able to stun 95% or more of the cattle with one shot.

 

 

 

Cattle vocalization (moos and bellows)

         Compared to 1999 vocalization scores have improved (Table 3). In 2000, 80% of the plants passed the vocalization audit with 3% or less of the cattle vocalizing. In 1999, 71% of the plants passed. In 2000 51% of the plants had excellent scores 0% to 1% of the cattle vocalizing. None of the plants in 2000 received a serious problem rating of over 10% of the cattle vocalizing. In 1999, two plants (5%) had serious problems when over 10% of the cattle vocalized during stunning and handling. In 2000 balking at the stun box entrance and refusing to move was the primary cause of vocalization. When cattle balk an electric prod is usually required to move them. Table 4 shows causes of vocalization. Table 5 shows that vocalization was higher in plants where a high percentage of cattle balked and backed up.

 

Electric Prod Use on Cattle – Forty-five percent of the plants had excellent scores on electric prod use. Throughout the plant’s entire system, 0 to 5% of the cattle were prodded with an electric prod. Fifty-seven percent (28) of the plants have completely eliminated electric prods in the crowd pen that leads up to the single file chute (Table 6). Seven plants (14%) had excessive use of electric prods. Only two of these plants had poorly trained employees who used electric prods on almost all of the cattle. Data was missing for 9 plants on prod use percentages due to misprinted audit forms.

 

Best Practices – A number of best practices are recommended for handling and stunning beef cattle (Chart 1).

 

Cattle Insensibility – All but one of the audited plants passed on insensibility on the bleed rail. However, there was a TV news report which showed serious problems with cattle abuse in a large plant. The report aired in two large cities. This video would have failed an audit for insensibility and electric prod use.

 

Problem Areas – Overall, the beef plants continue to improve but one problem area was cattle balking and refusing to enter stunning boxes or slipping in a stunning box. This can cause stunning and handling problems. The stunning boxes can be fixed by redesigning noisy gates and possibly slowing down line speeds.

         Another problem area is the formation of a two tier market. Plants which are audited on a regular basis by a large customer such as McDonalds will have higher welfare standards than plants which are not audited by a major customer. For example, plants that actively buy debilitated, skinny, non-ambulatory cattle will form a low end market which may be outside of an auditing system.

         Plants that process mature cows and bulls need to be careful with Herefords that have thick mats of curly hair on the forehead. Thick hair may reduce bolt velocity which is required for an effective stun. One Hereford cow had a possible sign of partial sensibility when it was shot correctly.

 

 

 

Summary for Pork Plants

         Nineteen Federally inspected pork slaughter plants were audited in eight different states. Eighty-nine percent (17) of the plants placed the stunning wand correctly on 99 to 100% of the pigs (Table 7). Sixty-eight percent of the plants (13) energized the stunning wand correctly so that 100% to 99% of the pigs remained quiet when the stunning wand was applied (Table 8). Two plants (10%) failed the stunning audit when scores for placement and “hot handing” were combined.  A “hot wand” is scored if the pig squeals when the stunner is applied. See 1999 report for scoring method (www.grandin.com), click on surveys.

 

Insensibility on the bleed rail – Eighty-four percent of the plants (16) rendered all pigs completely insensible on the bleed rail. In three plants, one or more pigs had eye reflexes but all other signs of return to sensibility were absent (Table 9). All pigs were completely insensible prior to scalding. Eight plants (42%) that had perfect stunning scores for both placement and absence of “hot wanding” had 100% insensible pigs. The two plants that failed on stunner placement and “hot wanding” had pigs with eye reflexes. These plants have been re-audited and the problems have been corrected.  See charts 2 and 3 for trouble shooting electrical stunning and determining insensibility.

 

Squeal Scoring – Improvements in pig handling have greatly reduced squealing during handling of pigs. Forty-four percent of the plants out of 18 scores had excellent scores (Table 10). One plant received a not acceptable rating. These improvements are due to two major factors, handling improvements and changes in pig genetics. Many producers have stopped breeding ultra lean nervous, excitable pigs which are difficult to handle.

 

Electric Prod Use on Pigs – Sixty-eight percent of the plants had eliminated the use of electric prods in the crowd pen which leads up to the single file chute (Table 11). Four plants (21%) had completely eliminated electric prods in the entire system. These four plants have line speeds of 860 or less pigs per hour per restrainer system. Only one plant received a not acceptable rating for electric prod use.

 

Best Practices – A number of best practices are recommended for stunning and handling pigs (chart 4).

 

Problem Area – Determining insensibility in electrically stunned pigs is more difficult than determining insensibility in cattle stunned with captive bolt. In cattle, any eye movement after stunning is a sign of a poor stun. In electrically stunned pigs some animals will have nystagmus (eye vibrating). This is permissible as long as all other signs of return to sensibility are absent. Nystagmus must not be confused with a natural blink where the eye closes and then reopens. Another problem is that poking the eyes of electrically stunned pigs with one’s finger may cause movements such as an eye that is stuck shut popping open. This is not a corneal reflex and it may fool an auditor into thinking that he/she found a pig that is starting to return to sensibility. To avoid these problems, it is best to observe without touching the eyes. If a pig does a natural blink like a live pig in the yards, the plant should be failed.

 

Conclusions – Stunning of beef cattle has continued to improve and handling of both cattle and pigs continue to get better and better. Many plants have greatly reduced electric prod use. The main problem areas that need to be fixed in a few plants are overloaded equipment and pig stunning procedures.

Table 1.        Captive bolt stunning in 49 beef plants in the U.S. during 2000.

 

Reason for poor stunning in 5 plants:

 

1.              Stunner maintenance

2.              Stunner ergonomics

3.              Wet cartridges

4.              Thick curly hair old Hereford cow

 

Table 2.        Comparison of announced versus unannounced audits on captive bolt stunning of cattle in 49 beef plants. This table only contains a plant’s initial 2000 audit.

 

 

There were significantly more plants in the un-announced audit group that had excellent stunning scores X² = 5.48 > .05 

         N = 24 Announced plants and 27unannounced plants.

 

 

         There were 24 plants which had announced audits and 27 plants that had unannounced audits. There were three plants where the unannounced audit was a re-audit. The first plant had a random unannounced re-audit and its stunning score was 99% for both audits. The second plant was re-audited because it failed the handling audit. Its first stunning scores was 96% and its unannounced stunning score was 97%. The third plant was re-audited because there was a sensible animal on the rail. Both audits were unannounced and the stunning scores were 97% and 98%.

 

Table 3.        Percentage of cattle vocalizing in 49 beef plants in the U.S. during 2000.

 

 

Vocalization percentages improved compared to 1999.  In 2000 79% of the plants had either excellent or acceptable vocalization percentages. In 1999, only 71% of the plants achieved this. In 1999, 2 plants (5%) had serious problem with over 10% of the cattle vocalizing.

 

Table 4.        Cause of vocalization percentages of over 3% in 10 out of 49 beef plants.

 

 

 

 

 

 

 

 

 

Table 5.        Vocalization is higher in beef plants with excessive balking.

 

 

         If a plant’s vocalization or electric prod score is not acceptable, balk score the plant to determine if the problem is caused by equipment or untrained or unsupervised people. High levels of balking and backing up are more likely to be an equipment problem.

 

Table 6.        Electric prod use in 49 beef plants.

 

 

         Percentage estimates were missing from five plants due to use of audit forms where the percentage of cattle electric prodded box was omitted.  It is unlikely that missing data plants would have been in the serious problem or not acceptable category.

Table 7.        Electric stunner wand placement on pigs in 19 U.S. pork plants for passage of current through the brain.

 

 

 

Reasons for poor wand placement

1.              Poor stunner wand ergonomics

2.              Line speed 1170 per hour at the restrainer.

 

Table 8.        Electric stunner “hot wanding” where the wand is energized before it fully contacts the pig. Scored yes if pig squeals when the wand is applied.

 

 

Reason for excessive hot wanding:

1.              Poor stunner wand ergonomics

2.              Defective switch on the stunning wand

3.              Line speed over 1060/hr

 

Table 9.   Plants with return to sensibility problems in 2000*.

 

1.     Eight pork plants (42%) with 100% correct placement and 0% hot wanding had 100% insensibility on the bleed rail. This shows that proper stunning procedures will produce 100% in sensible pigs.

2. All pigs were completely insensible prior to scalding. No righting reflexes or vocalization.
3. 63 out of 68 (94%) pork and beef plants had 100% complete insensibility during their McDonald’s audits.

 

*Note – One of the beef plants on this table was the plant that appeared on a TV news report. One hundred percent of the cattle were rendered insensible when the plant was re-audited.

 

Table 10.  Pig handling in 18 pork plants – Squeal scoring

 

 

     Squeal scoring is done by scoring each stunning cycle on a yes/no basis of quiet or heard a squeal anywhere in the stunning room. Hot wand squeals excluded.

 

Table 11.  Electric prod use in 19 pork plants.

 

 

 

(Chart 1)  Best Practices Cattle

1. Ergonomic handles on pneumatic stunners to make aiming easier.
2. Rack for rotating cartridge stunners to prevent overheating
3. Keep stunner cartridges in dry place.
4. Water spray to clean the trigger on a pneumatic stunner to prevent misfires.
5. Inspect restrainer weekly for broken parts.
6. Relocate restrainer controls per the stunner operator’s preference.
7. Use a water spray to induce the animal to raise its head for stunning.
8. Fill the crowd half full and move small groups.
9. Illuminate the restrainer or stun box entrance.
10. If animals balk at a reflection on the floor of the chute, move the ceiling lights off the center line of the chute.
11. Install a false floor in the conveyor restrainer to facilitate animal entry and reduce balking. It prevents the incoming animals from seeing the restrainer if above the plant floor.
12. Modify equipment to reduce noise.
13. People must stop yelling and whistling.
14. A non-electric driving aid should be a person’s primary tool for moving cattle. The electric prod should not be picked up unless an animal refuses to move into the stun box or restrainer.
15. Use flags, plastic bags and other non-electric driving aids to move cattle.
16. Eliminate electric prods in the crowd pen and staging area that leads to the crowd pen.
17. Have a person in bleed area to monitor insensibility.
18. Restrict electric prod to 5% or less of the cattle at the stunning box or restrainer entrance.
19. Eliminate distractions that make cattle balk and back up such as, shiny reflections, air drafts blowing towards approaching cattle, noisy gates, air hissing and dangling, moving chains.

 

 

 

 

Chart 2        Best Practices Pigs

 

1.              Use large 30 in (76 cm) by 30 in (76 cm) flags to move pigs. A flag is a light weight alternative to a heavy panel for moving pigs.

2.              Scratch a pig with a scrub brush to move it up the single file race.

3.              Cut off bottom 18 in (45 cm) to 24 in (60 cm) of a vertical slide gate and replace with conveyor belting curtain to prevent back bruises.  Pigs respect the solid barrier and they will not go through the curtain.

4.              Fill the crowd pen half full and move small groups.

5.              If animals balk at a reflection on the floor of the chute – move the ceiling lights off the center line of the chute.

6.              Install a false floor in a conveyor restrainer to facilitate animal entry and to reduce balking.

7.              Modify equipment to reduce noise.

8.              People must stop yelling and whistling.

9.              A non-electric driving aid should be a person’s primary tool for moving pigs. The electric prod should not be picked up unless an animal refuses to move.

10.           Monitor and improve bleeding practices to prevent return to sensibility.

11.           Use ergonomic principles to design both the work station and the electric stunning wand or tongs so that it is easy for the operator to place it in the correct position on the pig’s head.

12.           Rotate stunner operators often to prevent fatigue related stunning errors.

13.           Eliminate electric prods in the crowd pen and staging area that leads up to the crowd pen.

14.           Restrict electric prod use to 15% or less of the pigs at the restrainer entrance. In group handling systems that do not have single file races (chutes) electric prods should be eliminated.

15.           Eliminate distractions that make pigs balk and back up such as shiny reflections, air drafts blowing towards approaching pigs, poor lighting, dangling moving chains, etc.

 

Chart 3.       Trouble Shooting Return to Sensibility Problems in Electrically Stunned

Animals

 

Causes of Return to Sensibility:

 

1.              Insufficient electrical amperage to induce a grand mal epileptic seizure which is required to induce instant insensibility. The animal may blink within 5 seconds after stunning. In animals stunned with cardiac arrest equipment the blink will still occur but all signs of return to sensibility disappear at 60 seconds after stunning. This is a severe welfare problem because the pig will feel the shock and may be conscious but paralyzed. Must be corrected by increasing amperage or better electrical contact with the animal. This is especially a problem in sows.

2.              Poor Bleeding – Blinking or other return to sensibility signs occur 60 to 90 seconds after stunning. Improve bleeding technique.

3.              Poor Initial Contact – Blinking or other signs may occur 60 to 90 seconds after stunning. A common cause is a fatigued stunner operator. Rotate operators often. Poor initial contact often results in the animal not receiving sufficient stun time.

4.              Interrupted Contact – Blinking or other return to sensibility signs occur 60 to 90 seconds after stunning. On a manual stunner the wand or tongs bounces or slides during stunning. Stunner ergonomic design may need to be fixed or a malfunctioning automatic stunner needs to be re-adjusted.

5.              Wrong Placement – The electric current must pass through the brain, otherwise the animal will feel the shock. A head to body cardiac arrest stunner must never  be positioned with the head electrode on the neck. Placement of the head electrode of a head to body stunner on the animal’s jowl or below the jaw may fail to induce complete insensibility. The under the jaw position only works with a head only stunner with two electrodes which pass a current through the head.

6.              Stunning to Bleed Interval Too Long – This is mainly a problem with head only reversible stunning that does not induce cardiac arrest. Blinking and other signs of return to sensibility may occur 30 to 60 seconds after head only stunning.

Chart 4         Order of Events that Lead to Return of Sensibility After Head Only Electric

Stunning Without Bleeding

1.              Blinking and response to touching the eye.

2.              Response to needle prick on the nose (response to painful stimuli)

3.              Righting reflex – lifts head.

4.              Fully sensible.

Full return to sensibility occurs 15 to 20 seconds after the return of eye reflexes, Anil and McKinstry, 1992

Appendix 1

Assessment of Insensibility in a Plant

 

         Electrically stunned pigs are more difficult to assess for insensibility than captive bolt stunned cattle. In captive bolt stunned cattle, a rolled back eye or nystagmus (vibrating eye) are signs of a poorly stunned animal. In electrically stunned pigs which have been properly stunned. nystagmus is most likely to occur in pigs stunned with frequencies over 50 to 60 hz. Evaluation by the author of 700 pigs stunned correctly with 60 hz indicated that 1 to 2% had nystagmus 60 to 90 seconds after stunning and the eyes were either wide open or half open on most of the pigs. None of these pigs blinked spontaneously.

         Untrained plant personnel have had problems misinterpreting eye reflexes. Indiscriminant poking at the eyes of electrically stunned pigs can result in reactions that look like a corneal reflex, but it is not a real reflex. An eye stuck together with mucous can suddenly pop open when touched and pressing above the eye can force the lid closed.

         Practical experience gained during plant audits has shown that just watching for natural spontaneous blinks is a better approach for evaluating eye reflexes in electrically stunned pigs. Vibrating nystagmus is not a natural spontaneous blink. The author recommends that, plant personnel and restaurant welfare auditors should look at pigs blinking out in the holding pens to see what a natural blink looks like. All the blinking and eye reflexes discussed previously in the 2000 McDonald’s audit report were natural spontaneous blinks which occurred without touching the eye.

         The author is aware that eye reflexes and blinking in properly stunned pigs may occur before the pig has regained sensibility to pain (Anil and McKinstry, 1992). The order of return to sensibility is 1) eye reflexes,  2) response to a needle prick on the nose and then 3) return of the righting reflex. Complete return to full sensibility and consciousness occurs within 15 to 20 seconds after eye reflexes return.  If a stunned and bled pig responds by kicking the instant it touches the scalding water it may not be properly stunned and bled. This shows that it may be responding to a painful stimulus.

         Eye blinking is a welfare concern because the animal has either started the process of return to sensibility or it was stunned with insufficient amperage. A slaughter plant is not a laboratory and standards need to be conservative. The author recommends checking stunned pigs for blinking 60 to 90 seconds after stunning in plants where correct stunning amperages and stunner positioning have been verified and checking for blinking at both 5 seconds after stunning and 60 to 90 seconds after stunning in plants where stunning current and settings are not verified. Plant personnel, veterinary inspectors and welfare auditors should look at the head and ignore kicking. The only time kicking is a concern is when it occurs the instant a pig touches the scalding water. To put it simply, the head must be dead. Gasping like a fish out of water should be ignored but rhythmic breathing is an indicator of returning to sensibility.

         Some scientists have argued that blinking is not much of a concern because the pigs would still be in a state of surgical anesthesia. Judging the depth of surgical anesthesia is not a precise science. In the human literature, Dr. Donald Stanski (1994) cited 33 journal articles where people had awareness and remembered events during surgery. There appears to be no black and white dividing line between conscious and unconscious. Therefore, the criteria for properly stunned pigs needs to be very conservative. Simple corrections such as placing the stunner on the correct location on the pig’s head, increasing the amperage and better bleeding eliminated the spontaneous blinks which were observed during the audits.

 

References:

Anil, M.H. and McKinstry, J.L. 1992.  The effectiveness of high frequency electrical stunning in pigs. Meat Science 31:481-491.

Stanski, D.R. 1994. Monitoring the depth of anesthesia. In R.D.  Miller (editor) Anesthesia Vol. I, 4^th Edition, Churchill Livingstone, New York pp. 1127-1159.