Changes in Maternal: Young Associations with Increasing Age of Lambs

Abstract

A group of Merino ewes and their lambs was observed while grazing when the lambs were from 1 to 10 weeks old. Distances between lambs and their mothers or other nearest adults were recorded. Weekly recognition tests were also conducted to determine the time taken and patterns of movement of ewes to tethered lambs and lambs to tethered ewes. Mothers and their lambs were closely associated with one another for 75% of the time in the field, but variation existed between pairs. Mean distance between mother and lamb increased with lamb age, but mother and lamb when they were nearest neighbours were rarely more than 1 m apart. It was not until lambs were 6 weeks old that 80% could find their tethered mothers at 30 m. Post-weaning, 90% of lambs moved to their mothers even after a 2-month separation. When lambs were tethered, ewes moved to their lambs at 10 and 30 m for the initial 2-3 weeks, but after 4 weeks mothers rarely reached their lambs at either 10 or 30 m. These changes in behaviour pattern are discussed in relationship to the understanding and interpretation of ewe-lamb associations.