Abrupt weaning type combined to stress during late pregnancy in sheep present economic losses on carcass and low testicular development in lambs

Abstract

This study investigates the combined effect of the progressive or abrupt weaning after the stress during middle and late pregnancy on performance and development of lambs. Twenty-four male lambs were used, born from 18 Santa Ines ewes that were divided into three experimental groups. Pregnant ewes were submitted to the application of Lipolysaccharides E. coli (LPS) during the 70 th day of pregnancy (Ig; n=12) or at the 120 th day (Fg; n=8). Animals were kept as control (Cg; n=14). Lambs born in a 6 day interval were subjected to two types of weaning (Pw: progressive weaning; Aw: abrupt weaning at 45 days of age). Lamb data, including testicular development, yield carcass and economic cost were analyzed. Means were compared by F test and Student's t test (P<0.05). Fg lambs had the lowest average carcass weight compared with Cg and Fg groups (P<0.05) and lambs from progressive weaning had higher carcass weight in relation to the abrupt weaning process (P<0.05). On carcass yield, no difference was observed on gestation groups for any type of weaning (P>0.05). The highest yields in gross margin was observed for the Cg group and the lowest for Fg (P<0.05), and no difference to Ig group (P>0.05). On lambs’ testicular weight, Cg average value was higher than Fg (P<0.05), but no difference was observed on scrotal circumference (P>0.05). The combined effect of LPS challenge as a simulated disease process during late pregnancy and abrupt weaning change the testicular weight and the yield carcass, resulting in economic losses.