Date of Award:


Document Type:


Degree Name:

Doctor of Philosophy (PhD)


Natural Resources

Department name when degree awarded

Wildlife Resources


J. Juan Spillett


The initial three years of a 10-year reproductive study of elk involved three major phases. A fourth was added because of convenience. Objective 1 was to ascertain pregnancy rates in yearling and mature elk by rectal palpation, associate these rates with subsequent fall cow/calf ratios, and to test concurrently an ultrasonic fetal heart detector. Rectally observed anatomical changes in gravid uteri of cattle were directly applicable to elk. Ultrasonic detections of pregnancies in elk and deer were unsuccessful.

Pregnancy rates in the 1969-70 winter of 100 and 0 percent, respectively, for 19 adult and five yearling elk were associated with subsequent pre- and post-season cow/calf ratios of 100/55 and 100/68. Pregnancy rates the next winter of 82 and 17 percent, respectively, for 60 adults and 23 yearlings resulted in pre- and post-season cow/calf ratios of 100/52 and 100/39. Pregnancy rates in the 1971-72 winter were 82 and eight percent, respectively, for 39 adults and 13 yearlings; compilation of data for the first three years of the study precluded inclusion of associated fall and winter cow/calf ratios.

Objective 2 was to determine the breeding efficiency of yearling male elk. Pregnancy rates were 86 and 93 percent, respectively, in 14 yearling-bred cows and 15 adult-bred cows in 1971. Rectal palpations revealed eight of 12 conceived in October from yearling breeding and 10 of 14 in September from adult breeding.

A peak in yearling breeding was estimated to have occurred between October 11 and October 25, as compared to two peaks in adult breeding estimated near September 5 and September 20, The earliest and latest conceptions were estimated near October 5 and November 21, and September 5 and November 3, respectively, in yearling and adult bred cows. Most wild and captive yearlings polished or began peeling their antlers about October 1. compared to August 15 for captive adults.

Data suggested recrudescent testicular tissues had initiated a rise in blood androgen, which coincided with a peak in breeding activity in September and October.

lnducement of twin births in Objective 3 was attempted via synchronized superovulations during the September rut in 1970. Progestogen implants were used from 14 to 20 days to synchronize elk in two pre-rut trials and one mid-rut trial.

Follicle-stimulating hormone (FSH) suspended in carboxy-methyl-cellulose (CMC), injected (intramuscular) coincident with implant removal was judged superior to pregnant mares serum (PMS) alone or FSH in peanut oil. Injections of FSH in anestrous elk produced a mean of 2.4 follicles and corpora lutea (CL) (2.0 follicles and 1.33 CL), the first week, and PMS produced a mean of 9.67 follicles and CL (8.67 follicles and 1.5 CL) response was low in a pre-rut trial with two levels of FSH in peanut oil.

No conceptions apparently occurred in two groups of six cows injected with 15 and 20 milligrams FSH. Nine of 12 adults (including three of four controls) and none of four remaining yearlings were estimated to have conceived between September 30 and October 15 (five to 20 days after the treatment period), Two additional yearlings were superovulated with FSH without synchronization, but did not conceive.

Data presented from blood analyses in Objective 4 included mean values for free-ranging mature elk (probability value indicates a significant difference between free-ranging and captive mature elk). The values were: total leucocytes (WBC), 6160/cubic millimeter (cu mm); WBC differential (percent)--neutrophils (44), lymphocytes (48, P < .05), monocytes (1), eosinophils (7), and basophils (0.1, P< .01); erythrocytes, 11 million/cu mm; hemoglobin, 21 grams/100 milliliters (g%), (P< .01); packed cell volume, 53 percent; blood urea nitrogen, 36 Sigma units (P< .01); serum glutamic-oxalacetic transaminase, 91 Units; lactic dehydrogenase, 863 Units; alkaline phosphatase, 2.22 Sigma units (P < .01); total protein, 7.0 g% (P < .01); albumin, 3.8 g% (P < .05); globulin fractions (g%)--alpha1 (A4), alpha2 (.6) beta (.95), and gamma (1.98); glucose, 183 milligrams/100 milliliters (mg%), (P < .05); creatinine, 2.9 mg%; uric acid, 0.39 mg%; cholesterol, 80.5 mg%; total bilirubin, 0.65 mg%; inorganic phosphorous, 3.4 mg%; and calcium ion, 9.2 mg%. Serology for Brucella abortus and Leptos pira pomona was negative.

Blood values from five big game species and three species of domestic animals are presented for comparison. Significant differences in sampled elk were noted (P < .01 or < .05) in various tests between sexes, reproductive status, free-ranging and captive at different ages, and serial four-hour samples. A significant difference (P < .10) was noted in progestogen assays for non-pregnant and pregnant elk. Captive elk were positive and free-ranging were negative for Dictyocaulus infestations, Yearling and adult male reproductive tracts were microscopically differentiated. Nutritional conditions of experimental elk were considered excellent when fed a special pelleted formula freechoice with grass hay.