The objective of the present study was to investigate the variations of blood corpuscle and immunoglobulin G (IgG) of plasma and milk in sows fed placenta. The first experiment was designed with two groups, the experimental group (Ex: with placenta) and the control (Ct: without placenta) depending on whether they were fed placenta or not. The second experiment was designed using varying condition of placenta (fresh: Fp or cooked: Cp) and amounts of placenta (900 g or 1800 g) according to 2 × 2 factorial design. The number of erythrocytes were higher (P < 0.05) in Ct than in Ex on day 1 of Experiment 1. It was greater in Fp than in Cp on day 3 (P < 0.01) and day 8 (P < 0.05) in Experiment 2. The concentration of hemoglobin was greater (P < 0.05) in Fp than in Cp on day 3 in Experiment 2. In Experiment 1, the concentration of IgG in milk was significantly greater in Ex than in Ct on day 15 (P < 0.05) and day 20 (P < 0.01). In Experiment 2, the concentration of IgG in plasma was significantly greater in Fp than in Cp from day 3 to day 20 (P < 0.05). The concentration of IgG in milk was greater (P < 0.05) in Fp than in Cp on day 1 in Experiment 2. The results indicate that, when supplied as a feed, fresh placenta affected the IgG in the plasma and milk of sows.