7.2 Estimating simple forms of breeding values depending on heritability

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.
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Generation q Frequency Genetic load           ........ Change of rAI over heritabilities from 0 to 1 for the 6 cases ......

In all cells with initial values you can put data and press the Calculate button to see the results.


Example:
If you want to see how the program 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 measurements
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 = Population mean
A bar = Population 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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