# Specify variance structure in ASreml v3

I used ASreml to estimate genetic parameters for feed intake using bivariate and multivariate models.

However, I am very confused about how to define variance structures (even though I went through the "Users Guide" many times). Is there a quick way to check which models will be used in the R and G structures, such as when using the Unstructured, Identity, and Autoregressive models? How would I determine the initial values?

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