115 The Ramifications of Tail Docking Ewes on Mating Behavior and Reproductive Performance

Abstract

Abstract Removing a portion of the tail, also known as tail docking, is a common husbandry practice in sheep because it is believed to reduce fecal and urine soiling of the wool. However, support for this claim is sparse, and there is evidence that females of several ungulate species use their tails to communicate in sexual contexts. The objective of this study was to test whether the tail status of a ewe affected the mating preferences of a ram, the responses of the ewe to mounting attempts, conception rate, and litter size. Within 18 Polypay female twin pairs, one lamb was docked by placing a constrictive rubber ring on the tail between 24 to 48 hours of age and the tail of the other lamb was left intact (n = 18/treatment). Between 7 to 8 months of age, the estrus cycles of the ewes were synchronized and 9 groups of 2 twin pairs were exposed to an unfamiliar virgin ram (7 to 8 months of age) for 48 hours. Video footage of the first 2 hours of behavioral interactions was analyzed to determine which ewe the ram first approached, the duration of contact with each ewe, and the count of headbutts and rejected and accepted mounts. Undocked ewes tended to accept twice as many mounts from the ram when compared with docked ewes (X2 = 3.50, P = 0.06). Additionally, undocked ewes tended to reject fewer mounts (X2 = 0.3.72, P = 0.05). Undocked ewes were the targets of twice as many headbutts from the ram when compared with docked ewes (X2 = 19.50, P < 0.001). The analysis of which ewe the ram first approached and the duration of contact with each ewe is ongoing. Of the 36 ewes, 15 docked and 15 undocked ewes were bred, achieving an 83% conception rate. Based on ultrasounds 40 to 44 days post-breeding, tail status did not significantly influence prospective litter size (mean ± SE; docked: 1.73 ± 0.13; undocked: 1.93 ± 0.15; X2 = 1.04, P = 0.31). Our results show that tail docking did not influence the reproductive performance of ewes. However, the behavior of ewes and rams varied based on the tail status of the ewe, with rams targeting more aggression toward undocked ewes and undocked ewes showing greater sexual receptivity. Further research on the merits and pitfalls of tail docking is necessary to determine how this procedure holistically affects sheep welfare and performance.