Fostering in sheep: fostering lambs onto ewes whose lambs have died soon after birth

Abstract

Fostering, in which the odour of the foster lamb was made similar to that of the ewe's own lamb, was attempted with Merino and crossbred (Border Leicester x Merino) ewes whose lambs had been killed 30 min post partum to simulate natural early post partum death. Hessian coats were fitted at the time of death to the lambs of 11 ewes, and 2-1 8 h later the coats were transferred to foster lambs which were then presented to the respective ewes. The dead lambs of another 11 ewes were smeared with neatsfoot oil at the time of death and were left with their mothers for 2-18 h at which time they were substituted by foster lambs freshly smeared with neatsfoot oil. In another group of 11 ewes the skin of the dead lamb was draped about a foster lamb that was given to the ewe 2-18 h post partum. Foster ewes accepted 73 and 91% respectively of lambs treated with hessian coats or neatsfoot oil, compared with 36% in control ewes with untreated lambs, while fostering by the traditional shepherd's method of draping the skin of the dead lamb over the foster lamb was 100% successful. However, the success rates in the 3 treatments were not significantly different. Some success was also achieved in a supplementary group of 8 ewes when application of neatsfoot oil to the dead lamb was delayed until about 2 h prior to fostering. There was no indication that success rates were influenced by the genotype of the ewe or by restraining ewes overnight with the lamb having access to the udder. The traditional method of skinning the dead lamb appears to be the method of choice, because the dead lamb does not have to be found and treated prior to fostering.