Can the energetic supplementation of ewes influence the behavioral performance of their newborn lambs?

Abstract

The present work evaluated the effect of an energetic supplement (an extra 15% of the requirement) intake during the last month of gestation on the suckling behavior of neonatal lambs born from these ewes. The study was performed in a semi-intensive and commercial flock under hot sub humid tropical conditions. 12 Pelibuey ewes and their 20 newborn lambs were included. Five lamb behaviors were evaluated: number of vocalizations (NV), attempts to stand up (ASU), latency to keep stands (LKS), started looking for the udder (SLU) and achieved an effective suckling (AES). Twelve lambs conformed the control group [CG] and came from seven ewes which received an energetic supplementation of 7.37 megajoules of metabolizable energy per day (MJ EM/d). Likewise, eight lambs conformed the treatment group [TG] and came from five ewes which received a high energetic supplementation of 10.85 MJ EM/d. Both groups of ewes gave birth simultaneously. Response variables were initially categorized in low-or-high intensity using their quartile distribution and considering the median value as the reference point and analyzed post-hoc with the Fisher test. Behaviors of high and low intensity in lambs were similar in four of the five variables observed for both treatments. A significant difference was observed in the frequency of ASU, in lambs born from treated ewes when compared with lambs born from control ewes (P = 0.0281). The present results suggest that under semi-extensive breeding systems, the extra supplementation of ewes at 15 % of their energetic requirements during the last pregnancy month is reflected just in a slight improvement of the lamb’s behaviors.