How to Calculate Numerical Scores of Animal Welfare in Very Small Slaughter Plants

By Temple Grandin
Department of Animal Sciences
Colorado State University

It is difficult to determine percentages when very small groups of animals are scored. Normally 100 cattle, pigs, or sheep would be scored. A sample size of 100 animals makes it easy to determine accurate percentages. If only 50 animals are scored, a single fall would cause a plant to exceed the 1% limit on falling. The chart shows adjusted scores when an audit is done on less than 100 animals. The adjusted scores will prevent a plant from being penalized because the sample size is too small. In a very small sample of 10 or less animals, insensibility must be 100% and they must get a perfect score on two out of three variables of stunning, falling, and vocalization. They are allowed one non-compliance on either a missed stun, a single fall, or one animal vocalizing. When data in a small plant is pooled, the percentage for 100 animals should be used. The chart below has adjusted scores for single audits done with small samples.

Recommendations for Scoring Based on Sample Size (Pooled Data Should Use 100 Animal Percentages)
Number of Animals per Audit 100 Animals 50 Animals (single audit) 25 Animals (single audit) 10 or less Animals (single audit)
Captive Bolt Single Shot 95% 96% 96% *See Text
Electrical Stunner Correct Placement 99% 98% 96% *See Text
Insensibility 100% 100% 100% 100%
Vocalization 3% 4% 4% *See Text
Falling 1% 2% 4% *See Text
Dragging Sensible Animals 0% 0% 0% 0%
Clean Water Yes Yes Yes Yes

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