SERUM IMMUNOGLOBULIN TYPE-G CONCENTRATIONS IN CALVES PRODUCED BY IVF AND DELIVERED BY ELECTIVE CESAREAN-SECTION

Colostrum ingestion by neonatal calves is widely recognized to provide passive transfer of immunity. In this study immunoglobulin absorption from colostrum was evaluated in 54 IVF-produced calves. The IVF calve s were delivered by Cesarean section on Days 275 to 277 of gestation, 24 h after the dams had been administered 30 mg dexamethasone. The cal ves suckled bottles or were force-fed 6 L of colostrum in first 12 h o f life. Colostrum was obtained from the first post-calving milking of recipient dams or from frozen storage reserves if dam secretion was no t adequate. Immunoglobulin type G (IgG) content of both sources of col ostrum was determined. Serum samples from the calves were collected at 0, 12 and 24 h of age and analyzed for IgG. Twenty dairy calves born vaginally served as the controls and were subjected to the same colost rum management protocol except that the colostrum was obtained only fr om frozen post-calving milk of dairy cows from the same farm. The cont rol calves were also subjected to the same sampling protocol. The IVF group of calves ingested more IgG (P<0.0001) and absorbed more IgG by 24 h of age (P<0.0001) than their control group counterparts. Absorpti on of IgG was analyzed by comparing the g/kg body weight of IgG with s erum IgG values at corresponding times after birth. Colostrum absorpti on efficiency was the same for both IVF and control groups of carves a t 12 and 24 h of age. There was a maximum IgG dose above which additio nal IVF carves absorbed IgG were not realized. The slightly premature, Cesarean delivered increases in serum IgG from colostrum similarly to control calves delivered vaginally. (C) 1998 by Elsevier Science Inc.