Submitted to: Laterality: Asymmetries of Body, Brain and Cognition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/15/2011
Publication Date: 3/15/2013
Publication URL: http://handle.nal.usda.gov/10113/57161
Citation: Anderson, D.M., Murray, L.W. 2013. Sheep laterality. Laterality: Asymmetries of Body, Brain and Cognition. 18(2):179-193. Interpretive Summary: Little is known about a sheep’s turning preference when presented with a choice using an enclosed, artificially lighted T-maze. A total of 309 white-faced ewes were each evaluated once to determine their turning preference. Several types of data were collected on each sheep. Turning direction to leave the T-maze and alley chosen to return to peers was not uniform among the 309 ewes evaluated. A total of 66% exited the T-maze through the right arm and 34% through the left arm suggesting that these sheep had a turning preference. Furthermore, the exit arm and return alley were not chosen independently of each other. More than half (58%) of the ewes preferred to return to peers using the alley closest to the exit arm they chose when leaving the T-maze. However, laterality was not related to time of day the T-maze trial was run, age or breed of sheep, the ewe’s most recent liveweight, or its most recent shorn fleece weight. Furthermore, the mean time (21 s) spent in the start box was not related to exit arm or return alley chosen. Neither was mean time (15 s) spent in the T-maze related to exit arm or return alley chosen. These data may provide insight into designing working facilities and optimizing the use of labor involved in working white-faced sheep.
Technical Abstract: Turning preferences among 309 white-faced ewes were individually evaluated in an enclosed, artificially lighted, T-maze, followed by each ewe choosing either a right or left return alley to return to peers. Data recorded included time in the start box, time in the T-maze, exit arm chosen to leave the T-maze, and return alley. Right and left arms of the T-maze were chosen 65.7% and 34.3% of the time, respectively, while right and left return alleys were chosen 32.4% and 67.6%, respectively. Exit arm and return alley were not independently chosen (p < .0001), with observed counts being higher than expected under independence when ewes made the same choice for exit and alley (RR or LL turn patterns) and being lower than expected for alternating choices (RL or LR). Out of the 309 ewes, 28.2% and 30.1% chose RR and LL turn patterns, respectively, while 37.5% chose the RL turn pattern, but only 13 (4.2%) chose the LR turning pattern. Overall, ewes that initially turned right when presented a second turning opportunity had a slight preference to alternate their turning direction, while ewes that initially turned left tended to continue turning left when given another chance to turn. Exit arm and return alley laterality was not related (a = .05) to time of day the test was administered, ewe’s age or genetics, most recent liveweight, or most recent shorn fleece weight. The mean time spent in the start box (21 s) was not related to exit arm (p = .947) or return alley (p = .779). Mean time (15 s) spent in the T-maze was not related to exit arm (p = .086) or return alley (p = .952). More research will be required to understand sheep turning laterality and how it can impact working facilities and research equipment.