Genetic parameters for fleece quality assessed by an ancient Tzotzil indigenous evaluation system in Mexico

The University of Chiapas established in 1991 a flock of local criollo sheep from the Highlands of Chiapas to serve as an open nucleus for a genetic selection program. Its objective is to provide selected rams and ewes to the indigenous Tzotzil villages. From the perspective of the Tzotzil women, wool quality (TWQ) refers to a mix of diverse fleece characteristics. In this study, 2472 production records from the three varieties of Chiapas wool sheep were utilized, from the 1997–2004 period. Sheep are kept at the Centro Ovino Teopisca in Chiapas, Mexico. Individual TWQ is the mean of four fleece quality grades granted by Tzotzil shepherdesses prior to shearing within groups of contemporary animals in a truncated scale. Genetic parameters for TWQ, greasy fleece weight (FW) and staple length (SL) were estimated by using an animal model. TWQ had a mean (S.D.) of 3.12 (0.67), and h2 (S.E.) was 0.39 (0.05), while Re (S.E.) had a value of 0.48 (0.02). FW had a mean (S.D.) of 426 g (164), and h2 (S.E.) was 0.31 (0.05), while Re (S.E.) had a value of 0.51 (0.02). SL had a mean (S.D.) of 10.3 cm (2.45), and h2 (S.E.) was 0.43 (0.06), while Re (S.E.) had a value of 0.55 (0.02). Genetic correlation (S.E.) between TWQ and FW was 0.63 (0.04), between TWQ and SL was 0.98 (0.01), while between FW and SL was 0.47 (0.04). TWQ showed an important additive genetic component. Hence, its inclusion as selection criterion in a breeding program will prove useful. Repeatability for TWQ had a high value and it can be utilized as a criterion to keep animals within the nucleus flock.