Record Details
Factors affecting the mortality of pronghorn antelope in Oregon
ScholarsArchive at Oregon State University
| Field | Value |
|---|---|
| Title | Factors affecting the mortality of pronghorn antelope in Oregon |
| Names |
Yoakum, James Donovan
(creator) Dimick, Roland (advisor) |
| Date Issued | 1957-05-08 (iso8601) |
| Note | Graduation date: 1957 |
| Abstract | A study was undertaken to account for and authenticate all mortality factors affecting pronghorn antelope herds in Oregon. Work commenced in June, l954, and terminated in July, 1956. Information pertaining to antelope mortality in other states was also collected for comparison with Oregon conditions. Mortality factors investigated and their importance were: Prenatal and parturition deaths accounted for 14 of 370 carcasses located, or a known incidence of four per cent during the two-year study. Four of 89 carcasses examined manifested signs of old age. The only diseased antelope discovered through post mortem examinations were limited cases of single animals. Clinically diagnosed diseases were: "pinkeye" (Keratitis); "lumpy jaw" (Actinomycosis and/or Actinobacillosis); "Necrotic stomatitis" (Spherophorus necrophorus); "scours" (Diarrhea); pneumonia; and subcutaneous abscesses. The finding of liver flukes, Fasciola hepatica Linnaeus, may have been the first North American record of this parasite in pronghorn antelope. Weather conditions in relation to antelope survival were analyzed and it was believed that no mortality correlation existed between these two factors from l954 to 1956. Natural accidents such as miring in muddy lakes, drowning, and locking horns were occasion1ly reported in records previous to l954, but no records were found for subsequent years. Road kills were the largest known single factor in the category of man-influenced accidents. The problem of predator-antelope relationships was not investigated in detail although several observations were recorded. For 15 years, antelope hunters in Oregon have harvested an annual kill of 3.7 per cent of the estimated annual population, or an average take of 512 animals for an average estimated annual population of l3,854. The illegal or "poaching" kill of antelope was not found to have been a serious problem in southeastern Oregon. "Accidental" killings of does and kids during the hunting seasons were three times greater than poaching losses occurring the remainder of the year. A total of 370 antelope carcasses was collected. This datum was classified as to sex and age, estimated season of death, and per cent mortality by age group. Based on present knowledge, no single or combination of decimating agents could be uncovered as limiting factors in holding antelope in Oregon at a static population level. However, indications were noted whereby antelope densities and kid:adult ratios were highest on ranges with a greater vegetation interspersion and edge effect. |
| Genre | Thesis |
| Topic | Antelopes |
| Identifier | http://hdl.handle.net/1957/10490 |
