Master of Science (MS)


Animal Science (Animal, Dairy, and Poultry Sciences)

Document Type



Three oryx species and nine of eighteen antelope species across three tribes are considered endangered by the IUCN. Though the common eland (Taurotragus oryx) is not endangered, it lends itself well to the adaption of domestic assisted reproductive techniques due to its large size and calm temperament (Hansen et al., 1985). For these techniques to be used efficiently however, the details of the estrous cycle need to be defined within this and other species. Previously, Nowak (1999) proposed the eland estrous cycle to be ~21 days. In addition to cycle length, specifics of the estrous cycle have yet to be defined and are the objectives of this project. The overall objective is the characterization of the common eland estrous cycle. Specific objectives were to (1) observe behavior peri-estrus (2) determine ovulatory follicle size and (3) produce hormone profiles. The study animals consisted of two groups of four eland females (n=8) housed as a single bachelorette herd at ACRES. Each group was administered both of two commercial estrus synchronization regimens: Lutalyse® protocol (Regimen 1) and altrenogest protocol (Regimen 2). Regimen 1 received PGF2á injections on day 0 and day 11. Regimen 2 received altrenogest for 7 days and given PGF2á on day 7. After regimen administration intensive sample collections were performed around time of expected estrus and then repeated at expected time of subsequent natural estrus: blood samples were taken every 12 hours and ultrasonography was performed every 24 hours until the disappearance of a large follicle. HeatWatch® patches were applied to detect mounting behavior. Mounts were recorded least often during late morning (0600 to 1200). Dominant and ovulatory follicle size was determined to be 7 to 10 mm in diameter and estrous cycle duration was 21 ± 1.6 days. A total of seven of 30 possible ovulations (23.3%) was detected across both regimens. Homosexual mounting behavior was recorded, though all mounts were 2 seconds or less. Although further work needs to be conducted to confirm, the parameters defined here should help in the application of reproductive techniques to nondomestic ungulates.



Document Availability at the Time of Submission

Release the entire work immediately for access worldwide.

Committee Chair

Robert A. Godke