The maternal-offspring relationship in tailed and docked ewes and their lambs

Maternal behavior in the hours after lambing is critical for establishing the lamb–dam bond. In rodents, early-life pain alters maternal behavior, but it is unclear whether routine painful procedures like tail docking have similar long-term effects in sheep. We tested whether neonatal tail docking in female lambs altered (1) their maternal behavior and their offspring’s behavior after lambing and (2) behavioral and physiological stress responses to separation. Polypay ewe lambs were tail docked using the rubber ring method between 24 and 36 h of age (n = 11) or left undocked (n = 10). At approximately 13 months of age, they gave birth to singleton (n = 6) or twin (n = 15) litters. Between 30 and 60 min after the last lamb’s birth, the ewe and her lamb(s) were moved to an individual maternity pen, where behaviors were video recorded for 2 h. Between 6 and 12 h after lambing, the lambs were separated from their dam for 15 min, with video recordings taken from 15 min before separation until 15 min after reunion. Eye temperatures of ewes and lambs were assessed using infrared thermography immediately before and after separation as indicators of physiological stress. For all video recordings, we analyzed the duration the ewe spent eating, pacing, lying, and grooming her lamb(s), as well as the duration the lambs spent wagging their tail, nursing, and lying. Transitions from lying to standing were also recorded for ewes and lambs in the 2-hour postnatal period. All models included the dam’s tail docking status as a fixed effect with litter size (singleton vs twin) as a factor covariate; separation models also included observation period (before, during, and after separation). We found no significant effect of the dam’s tail docking status on maternal and offspring behavior following lambing or on their responses to separation. However, lambs of undocked ewes tended to spend more time lying in the postnatal period compared to lambs of docked ewes. Behavioral changes during and after separation – including increased pacing and reduced eating in ewes during separation, and increased grooming and nursing following reunion – suggest that separation was stressful, regardless of the ewe’s tail docking status. No differences were observed in eye temperatures before and after separation. Overall, we did not find evidence to suggest that neonatal tail docking impairs the ewe’s ability to bond with or care for her lambs later in life.