TYPE CLASSIFICATION IN ZEBU COWS - GENETIC-PARAMETERS

The main genetic parameters of type classification in Zebu cows in Cub a were estimated by the method of restricted maximum likelihood The he ritability values (h(2)) were:h(2) = .185 to h(2) = .201 for all trait s, except h(2) = .130 for final classification and h(2) = .121 for leg s and hoofs. On the other hand,genetic correlations (R-g) ranged from R-g = .961 to R-g = .999, suggesting the same genetic basis. The genet ic and residual (Co)variances between dependent variables were used to estimate the breeding value (BV) of all animals through the multitrai t animal model. Solutions to 166 047 equations were obtained, 16 086 c orresponded to animals with records and 7 522 were incorporated throug h the relationship matrix. The variations between the BVi of sires, da rns and progenies showed the possibilities for selection work and An i mportant phenotypic progress (Delta p) of Delta p = 2.82 for CI (gener al mean 73.9) was manifested and 37.3% was due to the genetic componen t of animals born in 1982 compared to those born in 1970. However, Del ta p = -1.45 units from 1983 to 1991 and only 18.6% corresponded to De lta g. Further research on this topic incorporating traits linked to p roductivity and longevity is needed.