The sex of the offspring affects the lamb and ewe responses to abrupt weaning

Abstract Female lambs have a stronger attachment with their mothers and show a greater susceptibility to stressors than male lambs. Male lambs grow faster than female lambs do, achieving a greater nutritional independence from their mothers. Our hypothesis was that female lambs and their mothers are more susceptible to stress of abrupt weaning than male lambs and their mothers. The objective of this study was to compare the behavioral and physiological responses of female and male lambs and their mothers to abrupt weaning. Thirty single lambs from 30 multiparous Corriedale ewes (16 females and 14 males) were weaned at 90 days of age. Body weight of the lambs was recorded at birth, before and after abrupt weaning. Behavioral activity, blood proteins and hematocrit of the lambs and their mothers were also determined before and after weaning. At the day of weaning, ewes that reared male lambs were observed pacing more times than those that reared female lambs (P