Lamb Recognition of Own Ewe verses Alien Ewe by Auditory Cues

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.

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.

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

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

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

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

Test Area

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

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.

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

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.

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.

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.

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).

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.

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?

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?

References Barfield, C., Tang-Martinez, Z., and Trainer, J.M. (1994). Domestic calves (Bos taurus) recognize their own mothers by auditory cues. Ethology 97, 257-264. Shillito, E. (1975). A Comparison of the role of vision and hearing in lambs finding their own dams. Applied Animal Ethology 1, p. 369-377. 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. 260-271. Walser, E. S., Hageue, P., and Walters, E. (1982). Vocal communication between ewes and their own and alien lambs. Animal Behaviour 6, p.140-150. Walser, E. S., Hageue, P., and Walters, E. (1983). A statistical analysis of vocal communication between ewes and lambs. Animal Behaviour 3, p. 146-155.