This study was conducted to find out the effect of newborn buffalo calves' gender, and the effect of maternal vaccination before birth using (Scour guard-4k) on the concentration of some blood components in the new born calves (Immunoglobulin G (IgG), insulin-like growth factor hormone (IGF-1), triiodothyronine T3 hormone and thyroxine hormoneT4) by taken blood samples from the calves immediately after birth and then after 6, 12 and 24 hours after birth. And the calves were also weighed at birth immediately and then re-weighed every 15 days until weaning, as well as recording cases of diarrhea during the first three days of the animal's life (The colostrum feeding period), and the duration until recovery. 16 new born Buffalo calves were divided into 4 groups (Four animals in each group) 1- Male calves born from vaccinated mothers 2- Female calves born from vaccinated mothers 3- Male calves born from unvaccinated mothers 4 - Female calves born from unvaccinated mothers. Male calves had a higher blood concentrationof IgG,IGF-1and T4.Therewasno significant difference in the blood concentration of T3 between male and female calves. Maternal vaccination before birth had a significant effect on the concentration of IgG and IGF-1 in calf blood serum. The concentration of T3, T4 hor; mones increased in the blood serum of calves born from unvaccinated dams. Male calves of vaccinated dams achieved the highest birth weight and the
highest weight gain until weaning. No cases of diarrhea were recorded in the group of male calves of vaccinated dams