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Genetic parameters of litter traits in three pig breeds in southern Brazil

Frank Siewerdt^I; Ricardo A. Cardellino^II; Valmir Costa da Rosa^III

^IDepartamento de Matemática, Estatistica e Computação, Universidade Federal de Pelotas, 96010-900 Pelotas, RS, Brasil
^IIDepartamento de Zootecnia, Universidade Federal de Pelotas, 96010-900 Pelotas, RS, Brasil. Pesquisador bolsista do CNPq. Send correspondence to R.A.C.
^IIIMinistério da Agricultura e Reforma Agrária (MARA) e Associação Brasileira de Criadores de Suínos, 95880-000 Estrela, RS, Brasil

ABSTRACT

This paper reports estimates of genetic parameters for litter traits, obtained in three pig breeds in southern Brazil. A sample of 7064 Large White (LW), 4538 Landrace (LR), and 2400 Duroc (DC) litters was analyzed with a mixed model that included a set of fixed effects (farm, month and year of parity, and age of sow at parity) and the random effects of boar within farm, and daughter within boar. Each sow farrowed at least two litters. Heritability estimates and corresponding standard errors were: (1) total number of piglets horn, 0.062 + 0.023 (LW), 0.121 + 0.033 (LR), and 0.078 + 0.044 (DC); (2) number of piglets born alive, 0.060 + 0.023 (LW), 0.119 + 0.033 (LR), and 0.073 + 0.043 (DC); (3) piglets alive at day 21, 0.075 + 0.024 (LW), 0.101 + 0.031 (LR), and 0.083 + 0.044 (DC); (4) litter weight at birth, 0.151 + 0.30 (LW), 0.155 + 0.037 (LR), and 0.109 + 0.048 (DC), and; (5) litter weight at day 21, 0.133 + 0.028 (LW), 0.143 + 0.035 (LR), and 0.174 + 0.056 (DC). The LR breed had the greatest amount of genetic variability for litter size traits and in general, the heritabilities of litter weight traits had larger values than those of litter size traits. The genetic correlations among the five traits, with three exceptions, were high, suggesting the presence of favourable pleiotropic effects. These high correlations also reflect the part-whole relationships among traits.

Keywords: genetic parameters; litter traits; pig breeds.

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