Transfer of antibodies against the CPD virus through colostrum and milk.

Newborn lamb immunoglobulins are of maternal origin and the transfer is done exclusively by colostrum and milk (syndesmochorial placentation). Antibody levels in colostrum and in maternal serum are the same at the moment of lambing. Milk antibodies are synthesized by cells which invade the udder at the end of the milking period. We immunized ewes with C.P.D. virus during gestation or at the end of lactation and we evaluated the presence of specific neutralizing antibodies in colostrum, in milk and in the sera of the mother and lamb. We recommend vaccination during pregnancy for ewes which are not going to feed their lambs: colostral given protection persists for 3 or 4 weeks. Ewe vaccination when the udder dried up is the choice when natural suckling is used: the lamb is protected as long as it is with its mother. In the conditions used in this work the steroid injection did not interfere with colostral antibody transmission.