Body condition score at lambing and performance of Santa Inês ewes with an offspring during lactation

Abstract

The main objective of this research work was to evaluate the performance of Santa Inês ewes according to their body condition score (BCS) at lambing. Data from 135 adult ewes, with singletons, were used. Ewes were divided into three distinct groups: 1) Bellow average: BCS less than 2.5 points (n = 44); 2) Average: BCS between 2.5 and 3.0 (n = 53); and 3) Above average: BCS greater than 3.0 (n = 38). The scale for BCS varied from 1 (very poor) to 5 (very fat). The individual BW, BCS, metabolic profile, milk production and composition of ewes as well as their lambs’ performance until weaning were considered. Metabolic profile was monitored at -7, +7 and +60 days relative to lambing. It was observed that ewes with higher BCS were also heavier; however, there were no differences among the groups for weights of lambs at birth and weaning (70 days). As there was no difference in milk production and composition, the average daily weight gain of the lambs was also similar for the different BCS groups. The metabolic profile (glucose, ?-hydroxibutyrate, cholesterol, creatinine, urea, hemoglobin, albumin, total protein and aspartate aminotransferase - AST) was also similar among the groups. However, when the metabolic profile was compared among the different physiological stages relative to lambing, some differences were observed. For example, ?-hydroxibutyrate was greater during the peripartum period, and glucose was greater in the lactation phase. As conclusion we could say that even in a situation of poor BCS, Santa Inês ewes have the physiological capacity to adapt themselves to the negative energy balance like those of the periparturient period. It seems that irrespective of the BCS, ewes prioritized lactation and were able to produce enough milk to accordingly nurse their lambs