7.2 Estimating simple forms of breeding values
The breeding value can be based on own, fathers + mothers record as well
as average of offspring or sibs to the animals. Heritability, repeatability,
common environmental effect (milieu) for full sibs and population mean
value have to be specified. In the last case relationship (a and a') shall be defined.
The relationship (a) between the related individuals giving
the phenotypic measurements; with the relationship (a') to the animal being evaluated.
The 'common milieu' is used when full sibs are measured.
In all cells with initial values you can put data (green fields) and
press the Calculate button. Results are rounded to four decimals.
Example:
If you want to see how the applet
work before you enter your own data just press the Calculate button using
the initial values.
In the figure below you see a regression line for the index (I) for
the true breeding value (A) of an individual based on measurements (average
of the records for offspring, sibs etc. = P's).. The coefficients of relationship can be defined in the
bottom line.
P'er = phenotype measurments
n = number of phenotypes
Pg bar = average of the P's
a' = relationship between the index animal and the P's
a = relationship between the P's
P bar = Populationen mean
A bar = Populations mean A's = P bar
h2 = heritability
c2 = common environmental factor for the P's
rAI = the accuracy of the index
t = a h2 + c2 = phenotypic correlation between P's
Questions:
Calculate the breeding value for the following animals when Mean=100 and the
heritability have the following values 5, 10, 25, 40 and 60 %.
own performance 110
average of the parents 115
10 half sib offspring 106
100 half sibs 105
Compare the results, which animal have the highest breeding value for
each heritability? And which one have the most accurate estimate for each heritability ?
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or back to the other applets