Introduction:

The Cebu Cuba Livestock Improvement Program (PMGC) has a control system based on the individual results of approximately 12,000 purebred females distributed throughout several herds throughout the country. Are recorded in young males, the weaning weight (PD); the live weight at 18 months (PF18), and in the females, calving interval (IPP), calving to conception interval (IPG), number of insemination per conception (NIA); length of gestation (DG) and pregnancy rate to first insemination (TG). However, until now only the PD and PF18 are the highest priority selection criteria. The objective of this study was to estimate the genetic parameters of these characters and, in accordance with the results, make the PMCG more efficient.

Method:

A total of 28776 records of IPP, IPG, NIA, TG and PD, from 23808 animal were studied with different mixed linear models with the purpose of estimating the components of (co) variance and the genetic parameters of these characters applying the ASreml3 software (Gilmour et al., 2009).

Results:

Age at birth had a beneficial effect on all traits except NIA. Heritability estimates (h2) for PD were 0.45 ± 0.05 and 0.21 ± 0.03 for direct and maternal effects respectively, whereas the genetic correlation between both effects was negative (- 0.57 ± 0.05); The heritability for IPP, IPG, NIA and TG were: 0.10 ± 0.03; 0.10 ± 0.03; 0.11 ± 0.03 and 0.08 ± 0.02, respectively. The bivariate models showed increases of 4 to 18% in the h2 for IPP (0.12 ± 0.01); IPG (0.11 ± 0.02) and NIA (0.12 ± 0.03) and close to 45% for TG (0.14 ± 0.04) with respect to those estimated by univariate models. The multivariate models showed an 18% increase in the precision of the genetic values of the bulls. Analysis of principal components showed that the first two eigenvalues (ei) explain 93-99% of the total genetic variance and in a bicarácter evaluation scenario using PD and IPP or PD with IPG, the second component explained about 20% of the variance between the genetic values for these traits. With the use of the coefficients of the second ei as the VG weighting index, it was possible to identify animals that simultaneously improve both the PD and the reproductive traits IPP or IPG.

Discussion or Conclusion:

The selection by applying the coefficients of the first and second eigenvalues produce positive responses in PD and IPP mitigating the antagonistic effects of direct and maternal effects on weaning weight. It is recommended to treat multivariate models to increase the accuracy of the generic parameters of the reproductive traits due to a better use of the genetic (co)variances with characters of higher heritability level.

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