Stress induced meat quality problems such as dark cutters cause large monetary losses to the livestock industry. The National Beef Quality Audit estimates that dark cutters cost the beef industry $5 for every fed animal slaughtered. Dark cutting beef is darker and drier than normal and has a shorter shelf life. Good quality beef has a final pH value close to 5.5. At pH values of 5.8 and above, both the tenderness and keeping quality of the fresh chilled meat is adversely affected. High pH meat is unsuitable for the premium trade in vacuum-packed fresh meats, and, depending in the commercial use of the product, dark-cutting meat may be discounted by 10 percent or more. High meat pH is caused by an abnormally low concentration of lactic acid. Post mortem production of lactic acid requires an adequate content of glycogen in the muscles at slaughter. Ante mortem glycogen breakdown is triggered by increased adrenaline release in stressful situations, or by strenuous muscle activity.
To reduce stress, prevent fighting and preserve meat quality, strange animals should not be mixed shortly before slaughter. A majority of the dark-cutting in cattle is due to mounting behavior, and when strange bulls are mixed, the physical activity during fighting increases dark-cutting as well.
High financial losses are incurred by the livestock industry as a result of carcass bruising. Bruising is an impact injury that can occur at any stage in the transport chain and may be attributed to poor design of handling facilities, ignorant and abusive stockmanship, and poor road driving techniques during transportation. Contrary to popular belief, livestock can be bruised moments before slaughter and stunned cattle can be bruised until they are bled.
Dark cutting beef is caused by a combination of factors which stress the animal and deplete glycogen (muscle energy source) from its muscle.
Some of the factors which contribute to dark cutting and make cattle more susceptible are:
• Rapidly fluctuating temperature.
• Excessive use of growth promotive implants.
• Genetic factors: Some types of cattle are more susceptible.
• Rough handling.
• Bulls have more dark cutters than steers, cows, or heifers.
Five Tips for Good Handling
1. Move small groups of animals.
2. DO NOT overcrowd crowd pen – fill it only 1/2 full.
3. Handlers should understand the basic concepts of flight zone and point of balance.
4. Ranches and facilities must have non-slip flooring.
5. Keep animals calm. Calm and quiet animals move more easily.
This information was used with permission from Dr. Temple Grandin. Good reviews on dark cutting beef can be found by visiting www.ozarksfn.com, where a link is provided to Dr. Temple Grandin's website; www.templegrandin.com.
