The increasing processes of body and heart weight, the index changes of heart to body weight ratio and of heart walls thickness (ventricular and inter ventricular) were studied on 160 goat fetuses (2groups male and female) from 7 to 22 week ages (at the first to the end of fetal period). Data analysis in SPSS and by ANOV A showed that the influence of age in all of 6 studied parameters was signified (p<0.01).conclusion: The increasing process of heart weight is followed by ageing and by Body weight. The index of heart to body weight ratio decreases while the body weight increases. The Average of maximum thickness of left ventricle wall is more than, interventricular (septum) and of this is more than of right, frequently. The increasing processes of thickness for left ventricle and septum are similar, while the right has an independence model.
Key words: Fetus, heart, goat, developmental growth, ventricular wall.