Copyright #{174}1974 by The Society for the Study of Re1,roduction. AU rights of reproduction in any form reserved. Observations on Bull Sperm Rotation

Three sets of cinematographic observations are described which attempt to ascertain both whether bull sperm roll, as opposed to rock, and in what direction such rocking or rolling occurs. The first set utilizes the flash shape sequence of the spermatozoan head, the second involves sequential views of asymmetric heads, and the third has to do with the flash color sequence of the head. It is concluded that bull sperm roll and that they roll both left- and right-handedly. The presence of three-dimensional move-ment has long been observed in sperma-tozoa either in the form of a tailwave which is not limited to a plane at any in-stant of time or in the form of a slow roll which causes the mainly two-dimensional tailwave to rotate. A spermatozoon may acquire a rotational component to its mo-tion during its maturation as it passes through the epididymis (Gaddum, 1988). Rikmenspoel (1965) has claimed that ejac-ulated bull sperm which do not rotate are pathological. Further, Phillips (1972) has suggested that the ability of rodent sperm of several species to traverse a straight j:iath is dependent on their flipping out of plane. Important propulsion and energy implications for certain kinds of nonplanar motion wave have been analyzed by Taylor (1952), Chwang and Wu (1971), and Coakley and Holwill (1972). The exact nature of three-dimensional spermatozoan movement is still unclear Gray, 1958; Rothschild, 1962; Fray, Hoffer, and Fawcett, 1972), and its exis-tence in some species has been questioned. With the aid of high-speed cinematog-raphy, this study attempts to determine whether bull sperm undergo a continuing 360#{176}rotation (roll) as they propel them-selves or whether they simply flip back and forth (rock). The present observations will not only help to clarify both the existence and nature of the rotational motion of bull spermatozoa, but will also suggest ways to analyze aspects of three-dimensional movement in other sperm