Do ewes recognize their lambs within the first day postpartum without the help of olfactory cues?

Two studies were carried out to test the ability of Préalpes du Sud x Lacaune (Study 1) and Rambouillet ewes (Study 2) to recognize their lambs during the first 24 h postpartum. Ewes were given the choice between their own and an alien lamb of approximately the same age, in a triangular pen of 10 m×10 m×10 m. A lamb was placed in each of the two corners while the mother was released from the third corner. Direct access to the lambs was prevented by an open barrier located at 1 m from the pens in which the lambs were kept. Ewes were studied at 8 h (n=10, 12), 12 h (n=20, 10) and 24 h postpartum (n=29, 9; Study 1 and Study 2 respectively). Tests lasted 3 and 5 min in Study 1 and 2, respectively. Although the first choice of the ewes did not differ from random, in both studies mothers spent significantly more time near their own lamb than near the alien. In both breeds a significant preference for the own lamb was already present at 8 h (P<0.05). We conclude that ewes are very likely to recognize their lamb without the aid of olfactory cues as early as 8 h postpartum, which is much sooner than thought from previous studies.