When animal welfare pays off

by Dr. Temple Grandin
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In both cattle and pigs, careful, quiet handling shortly before slaughter is essential for the best meat quality. Agitation, excitement and electric prod use within the last five to 15 minutes before slaughter will lower the meat quality in both cattle and pigs.

Dr. Robyn Warner, an adjunct associate professor at the Univ. of Melbourne, and her colleagues in Australia found that shocking cattle repeatedly 15 minutes before slaughter resulted in tougher meat. Many plants are working hard to really fine-tune their cattle handling methods. I recently visited a large fed-beef plant and worked with both the manager and employees. Our focus was on timing bunches of cattle. They were also instructed to fill the crowd pen that leads up to the single-file chute only half full. Timing small bunches of animals is essential so that they flow quietly through the crowd pen and into the single-file chute. Before cattle or pigs are brought into the crowd pen, the single file chute should be allowed to become partially empty. This enables the cattle or pigs to move quietly through the crowd pen without stopping, and they will follow the leader into the single-file chute. If the crowd pen is filled when the chute is full, the animals tend to turn around and it will be more difficult to get them to leave the crowd pen. Timing of bunches is one of the best methods for eliminating electric prods in the crowd pen. To help you conceptualize this idea, you should rename the crowd pen the “passing-through” pen.

Researchers have developed a new behavioral measure that indicates when cattle are starting to become stressed. At the first sign of a little bit of stress, the whites of the animal’s eye will show. Eye white will usually show up before cattle will start vocalizing or showing signs of physical agitation such as kicking, rearing or struggling. Eye white is a stress early warning sign. When handlers are doing a really good job of handling cattle, 50 percent to 90 percent of the cattle will reach the stunner with soft looking, dark eyes.

Measuring lactate in pigs

In pigs, high blood lactate levels are associated with more PSE and lower pork quality. Calm handling within five to 15 minutes before slaughter is essential to keep lactate levels low. Dr. Lily Edwards, a researcher at Kansas State Univ., found that higher lactate levels were associated with electric prod use, vocalization and jamming, rearing or backing up in the single file chute. All of these behavioral measurements were taken five to 10 minutes before stunning. Higher lactate levels were associated with lower pH values and higher drip loss. Drip loss is associated with more PSE and poorer pork quality. The blood lactate measurements were taken when the pigs were bled, and they varied from 4 mm to 20 mm. Lactate measurements at bleeding could be used as a practical way to objectively assess the quality of pig handling. In this experiment, lactate levels were measured using a small handheld analyzer that is similar to the glucose analyzers that are used by diabetics. The device is Lactate Scout, manufactured by EKF Diagnostic, GmbH, Magdeburg, Germany. Plant quality-assurance personnel could easily take random measurements. It would be especially useful for documenting groups of pigs that are difficult to handle. As the plants have become better at low stress handling, it has become increasingly obvious that certain producers need to work harder to produce pigs that will move easily. Some groups of pigs are almost impossible to handle quietly. This problem must be corrected at the farm. The producer should be charged a “handling fee” for handling downed pigs.

Dr. Temple Grandin operates Grandin Livestock Systems Inc., Fort Collins, Colo., and is a faculty member in the animal science department at Colorado State Univ.
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READER COMMENTS (1)

By Christophe Pelletier 6/25/2011 7:57:36 PM
These are not new findings. When I started working, in the pig business in the Netherlands, 25 years ago, we already knew that stress affected negatively the quality of the meat. We kept the pigs in pens when they were "showered" with a mist. This helped calming them down before slaughter and it was beneficial to the meat quality. PSE (Pale Soft Exudative) was a problem especially for ham producers, and stress sensitivity had been linked to genetics. A simple test to know whether the pigs carried the stress genes was the halothane test. Halothane is an anesthectic, and submitting the pigs to it revealed their genetic status. That way, the pig industry gradually eliminated the stress gene from the production chain. If PSE was a problem in pigs, DFD (Dark Firm Dry) was its equivalent in beef, although there was not any genetic cause detected in cattle as halothane positive in pigs. Similarly, in farmed salmon, the level of stress before killing also influences the quality of the flesh, in particular gapping in fillets was much worse with stressed fish. The use of CO2 appeared to have a negative effect, as the fish were desperately gasping for oxygen. What seems to cause poor flesh quality in stress animals is linked to the biochemical process after death. Stressed animals get into rigor mortis much faster than "relaxed" animals, and the transfer of calcium ions through the muscle cells membranes explain why the pH peaks and why the flesh quality (which is a direct expression of the muscle tissue toning) is affected negatively. Further, many other handlings of animals during the production period affect the quality of the neat products. I once reviewed many of the causes for quality downgrade of chickens in the slaughterhouse where I used to work. Any handling that could result in bruising or, worse, in bone fractures, clearly had a negative impact on the animal welfare, but also on the quality grade and eventually on the financial performance of the processing company. Other aspects like animal density in the chicken houses, leg problems because of quick growth, or wet litters also had many negative welfare, quality and financial consequences. Treating animal rights is always the right thing to do. It may require more training and may slightly increase costs at first, but it pays off very quickly.