Fostering lambs by odor transfer: the substitution experiment

Area of Science:

• Animal Behavior
• Reproductive Biology
• Olfactory Communication

Background:

• Ewes (female sheep) naturally use lamb-specific odors to distinguish their own offspring from alien lambs.
• Maternal recognition of newborns is crucial for reproductive success and lamb survival.

Purpose of the Study:

• To investigate the feasibility of using an odor-transfer technique to facilitate the adoption of alien lambs by postpartum ewes.
• To determine if transferring the scent of an ewe's own lamb to an alien lamb improves acceptance rates.

Main Methods:

• Cloth stockinettes were placed on newborn lambs of 37 multiparous ewes to collect lamb-specific odor.
• At 48–72 hours postpartum, alien lambs were introduced, either wearing the odor-impregnated stockinette of the ewe's own lamb (experimental group) or their own stockinette (control group).
• Lamb acceptance was monitored through behavioral observations over four days.

Main Results:

• 84% (26/31) of ewes accepted alien lambs when presented with their own lamb's odor.
• All control lambs (without transferred odor) were rejected by ewes.
• Maternal acceptance behaviors were observed in 85% of successful adoptions within 36 hours.

Conclusions:

• Transferring own-lamb odor to alien lambs is an effective and rapid technique for facilitating maternal acceptance.
• The presence of the ewe's own lamb's odor, rather than the absence of the alien lamb's odor, is the primary cue for acceptance.
• This odor-transfer method offers a practical solution for improving fostering success in sheep production.