SUMMARY

The aim of this research was to compare Projection Microscope (PMic) and Computerized Projection Microscope (CPMic) with Optical Fiber Diameter Analyzer (OFDA100), for the determination of the medullation in alpaca fibers expressed in percentage (MED). Fiber samples were taken from Pacomarca Scientific Station. Three experiments were carried out. At experiment 1, the MED was determined in 36 Huacaya alpaca males using PMic and OFDA100. At experiment 2, the MED was determined in 200 alpacas using CPMic and OFDA100 in Arequipa; and at experiment 3 carried out at Huancavelica, the MED was measured in 105 fiber samples with CPMic and OFDA100. OFDA medullation mean was very low in the three experiments (between 9.81±0.61 and 18.30±1.68%), compared with the total medullation obtained by the PMic (67.43±1.74%) and CPMic (between 28.71±1.37 and 41.14±2.00%).

The continuous medullation + strongly medullated fibers reported by CPMic was even greater than OFDA medullation. These results indicate that the OFDA100 procedure provides very low and different reports of MED than PMic and CPMic. Although the OFDA100 was a system for rapid evaluation of wool MED, it would not be recommended in alpaca fibers.

Keywords: Camelids. Fiber tester. Medullated fibers. Objectionable fibers.

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