The Reproductive Cycle of Male White-Tailed Deer in Central Texas

Abstract

A study of 50 male Texas white-tailed deer (Odocoileus virginianus) showed the reproductive cycle occurred in three phases: primary development, full production, and rest. This three-phase cycle had not been described previously. Initiation of antler growth was accompanied by partial stimulation of testicular development during the primary development phase. In the full production phase, the seminiferous tubules were stimulated further by some factor, presumably testosterone, which enabled spermatogenesis to proceed to maturity. These changes coincided with the shedding of the velvet from the antlers. Involution of the seminiferous tubules and abscision of the antlers were followed by a short period of testicular rest and were characteristic of the rest, the third phase. Peak spermatic production occurred in the latter half of November and early December. Fifty male specimens of Texas whitetailed deer from the Edwards Plateau of Texas in Mason, McCulloch, and Sutton counties, were collected to determine the normal reproductive cycle. A description of the reproductive behavior in white-tailed deer of the nearby Llano Basin has been published, but was primarily concerned with herd reproduction as determined by examination of female reproductive tracts and census data (Teer 1964). This study was designed to extend separate observations of the reproductive cycle of male deer in New York (Cheatum and Morton 1946), Massachusetts (Wislocki 1943), and southern Texas (Illige 1951). Our gratitude is expressed for the help and encouragement of Dr. C. H. Bridges, Mrs. Lucille Schultz, and R. Gardner. Additional thanks are expressed to Mrs. Dorthea Robinson for her typing skill and editorial efforts. METHODS Two male deer were collected at biweekly intervals throughout the year from September 1, 1962, to August 31, 1963, in Mason, McCulloch, and Sutton counties in the Edwards Plateau of central Texas. Immediately after collection, the deer were weighed and their ages estimated using the technique described by Severinghaus (1949). A necropsy was performed to observe the gross appearance of all organs and antler development of the deer. The testes were incised and preserved in 10 percent buffered formalin along with representative tissues of other organs. After fixation, the testes and accessory sex glands were dissected free from extraneous material and weighed. Tissue sections were cut from the testes approximately 4 mm from the incised surface, imbedded in paraffin, and sectioned at 6 microns. In the preparation of the sections for microscopic study, hematoxylin and eosin stains were routinely employed. Detailed observations of the sections were recorded and correlated with the gross appearance, testicular weights, and antler development. 1 This is a contribution of a cooperative project between the Texas Parks and Wildlife Department and the Department of Veterinary Pathology, College of Veterinary Medicine, through the Agricultural Experiment Station, Texas A & M University, supported by Pittman-Robertson Project W-90-R.