[Effect of ewe age on colostral immunoglobulin transfer to the lamb (author's transl)]

The plasmatic IgG concentrations were determined on 56 two-day old lambs and related to ewe age. They were found to increase slowly until the ewe was six years old (43.4 g/l) and then fall rapidly (11.2 g/l between eight to ten years of age). Colostral IgG concentrations at lambing were independent of ewe age but the older the dam, the lower their decrease between 0 and 12 hours after lambing. Less suckling activity by lambs from older ewes could explain this result. The high mortality rate of lambs born to older ewes observed in this flock might result from insufficient colostral transfer.