PrincipleScanning of the carcass by ultrasound results in a series of cross-sectional profiles that are used to gain tissue depths and other distances for prediction of the lean meat content of the whole carcass and several parts of the carcass. |
Error Sources
| Known standard deviations | |||
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Item |
Repeatability s(r) |
Reproducibility s(R) |
Reliability |
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Known possibilities for error |
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Error |
Frequency German observations |
Error contribution expressed as standard deviation German observations |
| Dry surface |
Practically never, the carcasses, coming from the dehairing drum, are always wet and smooth |
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| Rigid pigs - does not fit into the instrument |
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| Range of fat thickness > 40 mm |
Unknown problem, our pigs have fat thicknesses < 30 mm |
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| Dirty transducer |
The cleaning of transducers is part of the daily maintenance. Within one workday the contamination causes no error. |
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| Broken transducer | Can occur, caused by falling hook! | The consequences are unknown, because in the single known case, the failure was promptly noticed, and the instrument repaired. (The transducer was exchanged.) |
| Tick switch failure | In case of fall out any of the switches, the instrument stops | |
| Gambrel switch failure | and this stops the conveyor too. | |
It should be noted / documented which instrument that are used, and for each instrument the program version or EPROM number should be recorded to make it possible to track the used algorithm.
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Daily control |
Periodic control |
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Control of instrument |
Control of instrument |
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The instruments are controlled by a public officer in irregular intervals (2-3 times a year): -
the
transducer array is controlled by of a CD, different from that used in the daily tests. Once a year all instruments are re-calibrated
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Control of data |
Control of data |