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Journal of Animal Science Abstract - Animal Products

Head-only followed by cardiac arrest electrical stunning is an effective alternative to head-only electrical stunning in pigs1


This article in JAS

  1. Vol. 89 No. 5, p. 1412-1418
    Received: Feb 16, 2010
    Accepted: Dec 21, 2010
    Published: December 4, 2014

    2 Corresponding author(s): kurt.vogel@uwrf.edu

  1. K. D. Vogel 2,
  2. G. Badtram,
  3. J. R. Claus,
  4. T. Grandin*,
  5. S. Turpin,
  6. R. E. Weyker and
  7. E. Voogd§
  1. Department of Animal Science, Colorado State University, Fort Collins 80523;
    Wisconsin Department of Agriculture, Trade, and Consumer Protection, Division of Food Safety, Madison 53708;
    Department of Animal Sciences, University of Wisconsin, Madison 53706; and
    Voogd Consulting Inc., West Chicago, IL 60185



Many small slaughter facilities use head-only electrical stunning to render swine unconscious and insensible to pain before slaughter. Head-only electrical stunning is a reversible procedure that is optimally effective for approximately 15 s after stun completion. In many small North American slaughter plants, the authors have observed hoist speeds that are too slow to achieve a short enough stun-to-bleed interval to maintain insensibility through exsanguination. Unlike many European plants, there is no separate high-speed hoist for pigs and exsanguination on the floor is not condoned. As a result, a 2-stage stunning method was proposed where head-only stunning for 3 s was immediately followed by application of the same stunning wand to the cardiac region of the animal for 3 s while lying in lateral recumbancy. A paired-comparison study was conducted on 89 pigs in a small slaughter facility to compare the head-only method applied for 6 s with the head/heart method. The objective was to evaluate signs of return to sensibility, stun-to-bleed time, blood lactate concentration, muscle pH, drip loss, and fresh meat color to validate the head/heart electrical stunning method for small slaughter plants. Incidence of corneal reflex was not different (P > 0.05) between head/heart (93.8%) and head only (85%) stunning. Nose twitching was more common (P < 0.05) in head only (26.5%) than head/heart (5%) stunning. Head/heart stunning eliminated rhythmic breathing, natural blinking, eye tracking to moving objects, and righting reflex, which were all observed in head-only stunned pigs. Eye tracking to moving objects was observed in 40.8% of head-only stunned pigs. Blood lactate was not different (P > 0.05) between stunning methods (head only: 8.8 ± 0.7 mmol/L, head/heart: 7.8 ± 0.7 mmol/L). Stun-to-bleed time did not differ (P > 0.05; head only: 32 ± 1 s, head/heart: 33 ± 1 s). Mean time to loss of heartbeat with the head-only method was 121 ± 5 s. No heartbeat was observed with the head/heart method. Longissimus thoracis pH, color, and drip loss were not different (P > 0.05) between stunning methods. This study determined that the head/heart electrical stunning method reduces the incidence of signs of return to sensibility without significant effects on meat quality, plant operation speed, or blood lactate concentration. In addition, the head/heart method requires no capital investment for plants that are currently using the head-only method.

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