Sexual attractivity and receptivity in tailed and docked ewes

Abstract

Removing a portion of the tail, also known as tail docking, is commonly performed in sheep. However, there is evidence that females of small ruminant species use their tails to communicate in sexual contexts. The objective of this study was to test whether a ewe’s tail status affected the mating behavior of ewes and rams. Within 18 Polypay female twin pairs, one lamb was docked between 24 and 36 h of age by placing a constrictive rubber ring on the tail while her sister’s tail was left undocked (n = 18 lambs/treatment). The estrous cycles of the ewes were synchronized when they reached 7–8 months of age, and 9 groups of 4 ewes (2 twin pairs/group) were each exposed to a single unfamiliar virgin ram (n = 9; 7–8 months of age) for 48 h. Behavioral interactions were video recorded over the first 2 h and analyzed to determine the ram’s latency to investigate each ewe’s perineal region and to mount her, the duration of perineal investigation, the number of headbutts and mounting attempts towards the ewe, and the proportion of mounts that the ewe accepted out of the total attempted mounts. We used real-time location sensors to record the x, y location of ewes and rams every second, from which we determined each ewe’s total distance traveled and average distance to the ram. Undocked ewes tended to be mounted sooner by the ram and, when mounted, tended to accept more mounts compared to docked ewes. No differences were observed between docked and undocked ewes in any of the other behaviors. These findings suggest that tail docking neonatal ewe lambs may reduce sexual attractivity and receptivity later in life, with potential implications for reproductive success.