1. Lamb Recognition of Own Ewe verses Alien Ewe by Auditory Cues

2. Introduction Offspring Recognition
auditory imprinting affects ewes ability to recognize offspring starting 5 days after birth.
ewes bleat more to recordings of their own lambs than to alien lambs.
Auditory cues are important to lamb recognition.

3. Introduction Dam Recognition
Lambs vocalize more to recordings of their mother’s bleats than the bleats of alien’s.
Lambs will run to a covered pen containing their mother.
Ability peaks at 4 weeks of age.

4. Introduction
Objective: to determine if lambs can recognize their own ewe by auditory cues alone.

5. Materials 10 polypay Ewes and their Lambs Age of Lamb: 4-6weeks
Random Selection
Animals Provided by UCD Sheep Barn
High Quality Tape Recorder/ Players
Roll of Paper
Stopwatches

6. Methods - Preparation Record ewe vocalization Separation from lambs
Record own and alien ewes
2 minutes

7. Methods - Trials Lamb and ewe separation One lamb was tested at a time
Ewes were placed outside and the trials were done inside the barn
One lamb was tested at a time
Recording of own ewe on one side and alien ewe played on opposite side of the test area
Alternated every trial

8. Test Area

9. Records The first movement of the lamb
Duration of time spent on each side of the pen - 60 sec. Total
Last position of the Lamb

10. Results-Time Spent Average time spent on own ewe’s side = 31.9
Average time spent on alien ewe’s side=28.1
 Test used
=0.05
=16.92
 calc=85.76
There is a difference.

11. Results the lamb spent on each side of the pen
Mean (±Standard Deviation) time
the lamb spent on each side of the pen

12. Results-Initial Move 8 lambs moved toward own ewe
2 lambs moved toward alien ewe
Sign Test used
Confidence level P=0.10
Observed P=.055
The lambs move toward their mother at first.

13. Results-Last Position
4 lambs on own ewe’s side
6 lambs on alien ewe’s side
Sign Test used
Confidence Level P=0.10
Observed P=0.828
Lambs are not likely to end up on alien ewe’s side.

14. Discussion
Lambs use auditory cues to distinguish between own and alien ewes.
Lambs will run to covered pens containing their mother (Shillito 1975).
Lambs moved towards recordings of own ewe more often than recordings of alien ewes at the beginning of the trials.

15. Discussion Lambs can identify their dam by auditory cues.
Lamb spent more time on the side playing the recording of their dam than the alien ewe side.
Casual observation
Lambs bleat more in response to recordings their own ewe (Walser & Walters 1987).

16. Discussion Lambs may need further cues to reinforce correct dam.
Lambs paced between covered pens containing own or alien ewes (Shillito 1975).
Casual Observation of lambs pacing.
No difference between own and alien side of pen at the conclusion of the study.

17. Conclusions
Lambs were initially able to determine the location of their own dams.
Lambs spend more time on the side that their own ewe’s recording was played.
They showed no side preference at the end of the trial. Additional cues needed?

18. Further Studies
What is the relative importance of olfactory and visual cues in comparison to audio cues?
Is trying to push through side gates related to trying to reach the dam?

19. References
Barfield, C., Tang-Martinez, Z., and Trainer, J.M. (1994). Domestic calves (Bos taurus) recognize their own mothers by auditory cues. Ethology 97,
Shillito, E. (1975). A Comparison of the role of vision and hearing in lambs finding their own dams. Applied Animal Ethology 1, p
Walser, E. S., Hageue, P., and Walters, E. (1981). Vocal recognition of recorded lambs voices by ewes of three breeds of sheep. Animal Behaviour 8, p
Walser, E. S., Hageue, P., and Walters, E. (1982). Vocal communication between ewes and their own and alien lambs. Animal Behaviour 6, p
Walser, E. S., Hageue, P., and Walters, E. (1983). A statistical analysis of vocal communication between ewes and lambs. Animal Behaviour 3, p