Reducing Fatigue and Non-Ambulatory Pigs in Slaughter Plants to Improve Welfare and Pork Quality

"Fixing Fatigue"

By Dr. Temple Grandin
Dept of Animal Science
Colorado State University
meatpoultry@sosland.com
Meat and Poultry – August 2009

Updated February 2020

The industry needs to fix problems with downed, fatigued market-weight pigs. It is a problem that can be solved and the corrections must be made at the farms. The pork packing plants have greatly improved their handling practices over the last three years. Unfortunately, some plants still have very high numbers of fatigued pigs that cannot walk to the stunner. Fortunately, I have been in plants where there used to be high numbers of fatigued pigs and they have been greatly reduced. Unfortunately, I have also been to another plant where fatigue has become worse. This plant had excellent handling. All the plants I observed were processing large pigs with weights of 250 to 275 lbs (113 to 125 kg).

2020 Update

It is possible to almost eliminate fatigued, downed, non-ambulatory pigs. Recently I visited an abattoir that was processing large, finished (fattened) pigs that were over 125kg (275lbs) and I visited when the outdoor temperature was over 100F (38C). I watched them process over 2000 pigs and there was only one downed, non-ambulatory pig. To achieve such a low level of downed pigs, they made the following changes on the farm:

  1. Trained people on the farms to walk through the finishing pens every day. This trains the pigs to quietly walk away when people walk through them. Doing this will make it easier to load and unload trucks and move the animals.

  2. Changed their breeding program and eliminated genetic lines of pigs that had poor leg structure and conformation.

  3. Reduced or eliminated the use of ractopamine.

  4. Eliminated the PSS gene.

I am sick and tired of talking about fatigued pigs. We need to get rid of them and I have seen it done. The problem must be corrected at the farm. There are six basic causes of fatigued or downer pigs that are not able to walk to the stunner:

Injured pigs

Injured market pigs with a broken leg or other injury are not a major cause of the fatigued pigs that I have observed.

Rough handling

All the plants had excellent handling both in the plant and during truck unloading. Rough handling and excessive electric prod use can increase downers. The plants I observed moved all the pigs carefully and quietly.

Overloading trucks

Research conducted by Matt Ritter at the University of Illinois indicates even slight overloading of trucks will increase the percentage of downer and dead pigs. Some producers slightly overload trucks because they financially come out ahead on freight, even though the percentage of downer and dead pigs is increased. However, truck overloading was not the major cause of the downer problems that I saw corrected at two plants.

Poor leg conformation

Some genetic lines of lean hybrid pigs have terrible leg conformation. These pigs have feet and ankles that are structurally poor. The animals are either “post legged” with an ankle and hoof that is too straight or their ankles are collapsed and they walk on the dew claws. I have observed groups of these pigs where 50 percent or more of the market pigs were lame. The plants that made great improvements had producers who changed their genetics to pigs with better leg conformation. Genetic changes to improve structural conformation was a major factor in reducing downers.

Paylean Abuse

The two plants where I saw great reductions in downers have reduced, but not eliminated Paylean use. The lowest dose is still used in many of their pigs. Charging a handling fee in the $25 range for moving each downer pig solved the problem of overdosing pigs with Paylean. If a pig is not able to walk to the stunner, it costs the producers a handling fee to move it with the Bobcat or other device. Controlling the in discriminant use of Paylean was a major factor in reducing fatigued pigs in these two plants.

The PSS Gene

Porcine stress syndrome is a genetic condition which will cause both downers and death losses. Many breeders have eliminated the PSS condition. Both scientific studies and my observations indicate that breeders have reduced the incidence of PSS pigs. Ten to 15 years ago, PSS was a major cause of downers. It is easy to tell the difference between a downed pig with PSS and a fatigued pig that may go down due to a Paylean overdose or sore legs due to poor leg conformation. A PSS pig that goes down and is not able to walk will quiver and rapidly grunt with an open mouth. A fatigued pig that is not PSS simply lies down and refuses to move. It is silent and cool to the touch. After resting it may be willing to move. Fatigued pigs act like they have no energy for moving; I call it “running out of gas.” Cool, quiet, fatigued pigs were greatly reduced when a handling fee was implemented for moving downers to the stunner.

Again, the industry needs to fix the fatigued pig problem. In two large plants, I have seen fatigued pigs reduced - from 10 to 20 per hour of production to one per hour. Fatigued pigs are a problem that can be easily corrected.

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