ACKNOWLEDGEMENTS
We are grateful to Claudia Bieber and Gabrielle Stalder for technical advice, to Andrea Chirifre, Javier Millan and Jordi Grífols for conducting veterinarian work, to Antoni Arrizabalaga, Pilar Saborit and Silvia Miguez for logistic support and to Matthieu Stigler and Timothy Cline for helping with R packages.