Effect of restricting suckling on the social bond between ewes and their 10-week-old lambs

Abstract

To determine the effect of restricting suckling in the behaviour and welfare of sheep, 40 ewes and their 10-week-old lambs were assigned to one of the following treatments for 10 days: T1=lambs were free to suckle (control); T2=the udder of the ewe was smeared with faeces; T3=the udder of the ewe was covered; and T4=ewe and lamb were separated by a wire fence. In T1, T2 and T3, lambs remained with their mothers. No differences ( P>0.05) were found in food consumption or weight gains when treated groups were compared with the controls. Lambs in T2 and T3 performed the same number ( P>0.05) of suckle episodes with similar ( P>0.05) length, but less ( P<0.05) frequent and shorter that in T1. Ewes in all treatments vocalized more than those in the control group ( P<0.01). Among treatments, vocalization frequency in T4, remained higher for a longer period ( P<0.05) than in the other groups. No difference was found in vocalization frequency of lambs among treatments, but lambs in T1 tended to vocalize less ( P>0.05) than treated groups. Cortisol concentrations were similar ( P>0.05) in all treatments. At the end of the experiment, no difference was found ( P>0.05) in the number of lambs that attempted to suckle in treatments 2, 3 and 4 (30%, 30% and 20%, respectively). It was concluded that restricting 10-week-old lambs from suckling during a 10-day treatment period induced a minor short-term distress and the break of the social bond in 70–80% of the ewe–lamb pairs.