title: Two random terms with nlme
body: <p>I am performing a mixed model with <code>nlme</code> package in R. My situation is:
  The mixed model is: </p>
  
  <pre><code>MY = DFC + DFC2, random=~DFC|Animal, data=my_data)
  </code></pre>
  
  <p>where <code>Animal</code> is the random effect. 
  However, if I write the model like this, I can only obtain random intercept, and slope for <code>DFC</code> (by <code>Animal</code>), but not <code>DFC2</code>. 
  I would like to have also the random slope (by <code>Animal</code>) for <code>DFC2</code>!
  Could you please help me?</p>
  
  <p>Thank you very much,</p>