Animal Handling Troubleshooting Guide:
Tips for Solving Common Animal Handling Problems

By Dr. Temple Grandin
Meat & Poultry, March 2000

To meet the needs of today's customers, there will be a greater and greater demand for quality meat free of defects such as dark cutters and pale, soft exudative pork. Dark cutting beef is shunned by consumers because it's drier, darker and has a higher pH level and a shorter shelf-life. P.S.E. pork dries out because the meat has poor water binding capacity.

Animal handling and welfare is becoming an increasingly important issue to consumers, and major meat buyers such as McDonald's Corp., Oak Brook, Ill., are auditing handling and stunning practices. Most problems with handling animals are easy to fix. Retraining employees and better supervision will fix most problems. Regular auditing will help maintain good handling practices.

People manage the things they measure. High levels of vocalization during handling (squealing, mooing and bellowing) are a sign of handling problems. In beef plants with good handling, 3 percent or fewer of the cattle will vocalize. The best pork plants will have a stunning room that is quiet 50 percent of the time.

P.S.E. and dark cutters are caused by a combination of in-plant and off-plant factors. This trouble-shooting guide will help you to sort out these factors. Dark cutting occurs when the animal runs out of glycogen, the energy source for muscle. It is like a car running out of gas the car will run fine until the tank is empty. Some of the factors that drain the animal's reserve are severe weather changes, excessive growth promotant implants, rough handling and spending the night at the plant. No one factor causes a dark cutter; it is usually a combination of factors.

P.S.E. is caused by a combination of genetic and in-plant factors such as excessive electric prod use and poor chilling. Plants that improve handling in the stunning chute have a 10 percent reduction in P.S.E. The last five minutes in the stunning chute are critical. A good pig can be ruined just prior to stunning.

Use this guide to track down and fix in-plant and off-plant problems, which can be contributing to dark cutters or P.S.E. This guide will also help you to receive excellent scores on the McDonald's audit or audits by other customers.

Problem: High levels of dark cutting
Probable Causes Solutions
Cattle from certain feedlots are the source of a high percentage of the dark cutters. Work with the feedlot to reduce excessive use of growth promotant implants. TBA (a synthetic male hormone) and estrogen implants are associated with an increased susceptibility to dark cutters. These products should be used in moderation.
Some cattle from certain feedlots are agitated and difficult to handle. Some crossbred cattle with European Continental genetics are excitable. These animals should be trained to tolerate handlers on foot before they arrive at the packing plant. Cattle moved through a feedlot exclusively by horses may be difficult to handle by a person on foot at the plant.
High percentages of bullers, cattle that ride and mount each other, will have more dark cutters. Check implanted ears for crushed implants. At the feedlot provide more water troughs and possibly more bunk space. Cattle fighting over a crowded trough or feed bunk may have more bulling.
Cattle spending the night at the plant. Reduce the numbers of cattle held overnight.
Rough handling and excessive electric prod use. Retrain employees and refer to the balking section of this troubleshooting guide.
Sudden changes in temperature or extremely hot temperatures. This will have the greatest effect on nervous cattle or cattle that have been implanted to achieve the maximum possible weight gain. Dark cutting is most likely to occur 24 hours to 48 hours after a severe weather change. Slaughter the cattle immediately, or hold them at the feedlot for 10 days to two weeks to allow glycogen levels to be replenished.
Steers were castrated at a late age. Some producers do this to achieve high weight gain. Work with suppliers to castrate calves at a younger age.
Strange cattle are mixed together shortly before slaughter. Mounting, butting, and pushing use up the glycogen (energy) in the animal's muscles. Avoid mixing cattle from different feedlot pens or pastures. When cattle are mixed they fight to establish a new dominance order. It may take more than seven days for the cattle to replenish their glycogen levels.

Problem: High levels of pale, soft exudative pork
Probable Causes Solutions
Excessive use of electric prods in the stunning area. Retrain employees to improve animal movement. Get electric prods out of the employees' hands; they should sit on a rack most of the time. A plastic pipe, flag or paddle should be the primary driving tool.
Pigs from certain producers are excitable and difficult to drive. Advise producers to have workers walk in the pens every day during finishing to train pigs to quietly get up and flow around the person. Changes in genetics can also reduce this problem.
Pigs from some producers have high levels of P.S.E. even when they are handled quietly in the plant. The producer needs to change breeding stock to eliminate the stress gene or withdraw feed prior to shipping. Pigs full of feed have more P.S.E.
Large, heavy-weight pigs with big muscles have more P.S.E. than smaller pigs. This is most likely to occur during hot weather. Improve chilling. Larger pigs chill more slowly and retain more body heat Possibly change genetics. All pigs should be showered prior to stunning and rested for at least two hours.

Problem: Animals balk and refuse to move through the system. Constant use of electric prods is require to keep up with the line.
Probable Causes Solutions
Animals balk and refuse to enter the conveyor restrainer. Install a lamp, such as a dock light used at the truckloading area, to light the entrance. It should illuminate the entrance, and it must NOT glare directly into an approaching animal's eyes. If this does not work, check the hold-down rack It should not touch the animal's back If balking still occurs, it may be due to the lack of a false floor under the restrainer. Install a false floor made of steel or conveyor belting to prevent animals from seeing the steep drop-off under the restrainer. Check to make sure the animals do not see people or moving objects through the restrainer.
On a sunny day, animals refuse to enter under a building or roof, but they move easily on cloudy days or at night. Animals tend to move from a darker place to a brighter place. To admit more light, install white translucent skylights or side panels in the building to provide shadow-free light.
Sometimes animals move easily, and sometimes they are hard to drive for no apparent reason. Look for changes in air drafts blowing down chutes and alleys. Animals will balk if they feel air blowing on their faces in the stunning chute. Air drafts may change when different fans are turned on in the plant. Changes in wind direction and seasons can also change air drafts.
Cattle refuse to enter the stunning box. Attach a piece of conveyor belting to the bottom of the door to prevent the cattle from seeing the shackler's hands. Install muffling devices on air exhausts to reduce noise, or install a shield to prevent the cattle from seeing people or moving carcasses as they enter the box. Cattle will also balk if they see the feet of a previously stunned animal under the door.
Animals refuse to leave the crowd pen and enter the single-file chute. Retrain employees to move smaller bunches of cattle and pigs and fill the crowd pen half full. Cattle and pigs need room to turn. Sheep may be handled in large bunches. Look through the chute at the animals' eye level to look for distractions such as a moving piece of chain, water dripping in a reflecting puddle, shiny metal that jiggles or seeing people ahead. Repositioning lights on the ceiling will often help eliminate reflections. Avoid grates at the chute entrance.
Cattle or pigs balk in a main drive or at the scale. Look for moving objects that may not be obvious such as fan blades slowly moving in the wind or a piece of loose plastic or insulation on an overhead pipe.