Heifer disposition and bonding of lambs to heifers

Abusive and non-abusive (tolerant) heifers were individually identified during pen confinement with young sheep. Physical aggression by abusive heifers toward lambs included butting and kicking. Two groups of three 75-day-old lambs confined with tolerant heifers developed a bond after 20 days and a strong bond after 55 days. However, three lambs confined with abusive heifers were not bonded at 20 days, but formed a satisfactory bond with the cattle after 55 days as the cattle became more tolerant of the lambs. During pen confinement, lambs with abusive heifers spent 41% of the time in a creep area away from heifers. In contrast, lambs in two tolerant lamb-heifer groups spent only 15% of their time in the creep area. Heifers which are abusive to lambs should be identified and removed from lamb-heifer groups if bonding is to be accomplished consistently and efficiently.