Effect of selected on the changes in the performance traits and genetic parameters in two strains of ducks
2000
Kokoszynski, D. (Akademia Techniczno-Rolnicza, Bydgoszcz (Poland). Wydzial Zootechniczny)
Seven successive generations were analysed to define changes in the values of heritability coefficients and of the correlation calculated for traits in A55 and P77 strains. Low or average values of the heritability coefficients calculated for reproductive traits showed a downward trend in the two strains, while the values for meat traits increased in A55 ducks and decreased in P77 ducks. High, and increasing with years, coefficient values of the correlation between the meat weight and the fat weight make the selection to reduce the content of fat and to increase the content of muscle dificult. The 7-week-of-age-body-weight - related selection increases the value of the two traits, while the length-of-the-breast-bone - related selection may enhance the muscle content and decrease the fat content of the bird body
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