Compensatory Hypertrophy in the Remaining Testis Following Unilateral Orchidectomy in the Adult Ram

It is well known that in many mammalian species, including the sheep (Sundaram & Stob, 1967), unilateral ovariectomy leads to compensatory hypertrophy in the remaining ovary and an ovulation rate equal to that of the two ovaries in the control animals (Parkes, 1966). However, it has not been conclusively established that analogous compensatory changes occur in the remaining testis following unilateral orchidectomy. Although it has been shown in the hemicastrated adult rat that the remaining testis enlarges (Grant, 1957) and the epididymal sperm reserve increases to that of the two epididymides in the intact animals (Smelser, 1933), observations on the hemicastrated rabbit (Edwards, 1940) and other species (see Parkes, 1966) are conflicting. Previous studies were limited because of the lack of a technique for accurately assessing production