|
KMID : 1025520100520050349
|
|
Journal of Animal Science and Technology
2010 Volume.52 No. 5 p.349 ~ p.356
|
|
|
Estimation of Genetic Parameters for Litter Size and Sex Ratio in Yorkshire and Landrace Pigs
|
|
Lee Kyung-Soo
Kim Jong-Bok
Lee Jeong-Koo
|
|
|
Abstract
|
|
|
|
This study was conducted to estimate heritabilities, repeatabilities and rank correlation coefficients among breeding values for litter size and sex ratio of Yorkshire and Landrace pigs using various single trait animal models. The analyses were carried out the data comprising 26,390 litters of Yorkshire and 26,173 litters of Landrace collected from the year 1998 to 2008 at a private swine breeding farm located in central part of Korea. Five different analytical models were used for genetic parameter estimation. Model 1 was most simple basic model fitted with year-month contemporary group fixed effect, random additive genetic effect and random residual effect. Model 2 was similar to the model 1 but permanent maternal environmental effect added as random effect, and model 3 was similar with the model 2 but linear and quadratic effects of sow age were added as fixed covariate effect. Model 4 was similar as model 2 except that the parity was added as fixed effect and model 5 was similar to model 3 or model 4 but covariate of sow age was nested within parity effect. The results obtained in this study are summarized as follows: The means and standard error of total number of pigs born per litter(TNB) and number of pigs born alive per litter(NBA) were 11.35±0.02 and 10.04±0.02 for Yorkshire, 10.97±0.02 and 9.98±0.02 for Landrace, respectively. The sex ratio(percentage of female per litter) was 45.75±0.11% and 45.75±0.11% for Yorkshire and Landrace, respectively. The heritability estimates of TNB(0.243) and NBA(0.192) from model 1 tended to be higher than those from any other models in both breeds. Differences in heritability and repeatability for TNB were not large among models 3, 4 and 5 and same tendency of negligible differences among estimates by models 3, 4 and 5 were observed for NBA, where heritability and repeatability ranged from 0.096 to 0.099 and from 0.188 to 0.193, respectively, in Yorkshire; and ranged from 0.092 to 0.098 and from 0.193 and 0.196, respectively, in Landrace. The heritability estimates for sex ratio were close to zero which was ranged from 0.002 to 0.003 for TNB and from 0.001 to 0.003 for NBA over the models applied. The rank correlation coefficients of breeding values by model 1 with those from other models(model 2, 3, 4 and 5), and breeding values by model 2 with those from other models(model 1, 3, 4 and 5) were highly positive but lower than the coefficients among breeding values by model 3, model 4 and model 5 which were high of 0.99, approximately, for TNB and NBA of both breeds.
|
|
|
KEYWORD
|
|
|
Genetic parameters, Heritability, Litter size, Rank correlation, Sex ratio
|
|
|
FullTexts / Linksout information
|
|
|
|
|
|
Listed journal information
|
|
|
|
|