Study of the genetic parameters of selection traits in Ile de France sheep
Keywords:
sheep, Ile de France breed, genetic parametersAbstract
The aim of the study is to establish the genetic parameters of selection traits in Ile de France sheep.
Object of research are two sheep flocks: the Ist of 222 female animals, bred in the Agricultural Institute
in Stara Zagora and the IInd of 200 female animals in the Institute of Animal Science in Kostinbrod.
The study period is 5 years. The heritability of the traits live weight (at birth, at 10, 30 and 70 days
of age, at weaning, at 9 and 18 months) and fecundity (number of lambs born per ewe) has been
established. Repeatability of the traits and the correlations between them are also analyzed.
The regularities of the general genetic model are used for conducting the study:
Y = G + E and G = а + d + е.
The statistical model applied is based on the “Animal model” and is as follows:
Yijklmnop = HYMi
+ Breedj
+ Agek
+ SLl
+ LSm + Sexn
+ LWo
+ GT
p
+ eijĸlmnop
Insignificant and low values of heritability, repeatability and genetic correlations of the analyzed
traits of fertility and live weight have been found. This is an indicator of low genetic determinism of
variation and more significant influence of environmental factors, which suggests poor efficiency of
complete selection by phenotype.
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