Final answer:
Castrating pre-pubescent bulls causes them to grow in female proportions due to the absence of testosterone.
Step-by-step explanation:
Castrating pre-pubescent bulls causes them to grow in female proportions because the absence of testosterone allows the primitive gonads to develop into ovaries instead of testes. This leads to the development of female sexual organs and characteristics, such as the growth of female reproductive organs and the redistribution of fat towards hips and breasts.