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P. De, A. Vieira, M. A. Von-keyserlingk, and D. M. Weary, Presence of an older xiii weaned companion influences feeding behavior and improves performance of dairy calves before and after weaning from milk, Journal of Dairy Science, vol.95, pp.3218-3224, 2012.

P. De, A. Vieira, A. M. De-passillé, and D. M. Weary, Effects of the early social environment on behavioral responses of dairy calves to novel events, Journal of Dairy Science, vol.95, pp.5149-5155, 2012.

P. De, A. Vieira, M. A. Von-keyserlingk, and D. M. Weary, Effects of pair versus single housing on performance and behavior of dairy calves before and after weaning from milk, Journal of Dairy Science, vol.93, pp.3079-3085, 2010.

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DOI : 10.1016/0166-4328(88)90157-X

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DOI : 10.1016/j.applanim.2005.10.012

F. Flower and D. M. Weary, Effects of early separation on the dairy cow and calf:, Applied Animal Behaviour Science, vol.70, issue.4, pp.275-284, 2001.
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C. A. Heidbreder, I. C. Weiss, and A. M. Domeney, Behavioral, neurochemical and endocrinological characterization of the early social isolation syndrome, Neuroscience, vol.100, issue.4, pp.749-768, 2000.
DOI : 10.1016/S0306-4522(00)00336-5

M. B. Jensen, K. S. Vestergaard, C. C. Krohn, and L. Munksgaard, Effect of single versus group housing and space allowance on responses of calves during open-field tests, Applied Animal Behaviour Science, vol.54, issue.2-3, pp.109-121, 1997.
DOI : 10.1016/S0168-1591(96)01183-5

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DOI : 10.1177/0269881108093842

E. S. Paul, E. J. Harding, and M. Mendl, Measuring emotional processes in animals: the utility of a cognitive approach, Neuroscience & Biobehavioral Reviews, vol.29, issue.3, pp.469-491, 2005.
DOI : 10.1016/j.neubiorev.2005.01.002