We evaluated the reliability of using cortisol concentrations in urine and feces to indicate stress responses in captive Rocky Mountain bighorn sheep (Ovis canadensis canadensis). Tests for parallelism and quantitative recovery of cortisol in bighorn plasma, urine, and fecal supernatant revealed that radioimmunoassay reliably measures cortisol in these media. High performance liquid chromatography confirmed the presence of cortisol in fecal extracts. In a randomized complete block experiment, we observed cortisol responses of eight bighorn sheep injected with either 0.0 or 0.50 U/kg of adrenocorticotrophic hormone (ACTH) gel delivered at 48 h intervals over a 29-day period. Treatment elevated (P < 0.01) cortisol in urine and fecal supernatant during 0–24 h following ACTH injections but levels dropped below those of controls during 24–48 h posttreatment. Magnitude of cortisol responses did not change with time during the experiment (time × treatment, P > 0.05). In a separate experiment, we observed short-term (0, 2, 4, 8, 12, 24 h) cortisol responses in plasma, urine, and feces from eight bighorns following a single challenge with 0.0, 0.25, 0.5, or 1.0 U/kg of repository corticotropin. Plasma cortisol concentrations rose within 2 h of treatment (P < 0.025) and remained elevated for at least 8 h. Urine cortisol excretion showed a similar trend with peak response delayed 2–6 h. Fecal cortisol trends resembled those of plasma and urine but were more variable. We failed to observe a dose response above the 0.5 U/kg level in any media. Concentrations of cortisol (ng/mL) in plasma correlated (r2 = 0.76) with cortisol:creatinine ratios (ng/mg) in urine. We conclude that measuring cortisol in excreta of bighorn sheep offers promise as a noninvasive means of sampling their responses to environmental stressors.
Muskox farming is an emerging industry in Alaska. For such an endeavor to succeed, it is necessary to develop fundamental husbandry tools specifically for this species. This study examined the role of the bull in the onset of seasonal ovarian activity and the synchrony of estrus and tested the efficacy of a radiotelemetric estrus detection system. Twenty parous female muskoxen, ranging in age from 4 to 15 yr, were divided into three groups (balanced by age and body weight). Groups received early bull exposure (EBE; August 1, n = 7), late bull exposure (LBE; August 22, n = 6), or remained physically isolated from a bull (NBE; n = 7). Just before bull introduction, radiotelemetry transmitters were attached to the rump of muskox cows in the EBE and LBE groups. Plasma samples were collected from all the cows twice weekly and analyzed for progesterone (P4). The mean date of onset of seasonal ovarian activity was earlier in the EBE and LBE groups than in the NBE group (P < 0.001) and was earlier in EBE (P < 0.021) than in LBE. All EBE and LBE cows conceived to the first fertile cycle, giving 100% fertility. The time interval for the onset of ovarian activity between the first and last cow within each group was 7 d in the EBE group, 12 d in the LBE group, and 24 d in the NBE group. Radiotelemetry correctly identified estrus 95% of the time (18 of 19 instances). Mean length of estrus for each cow, calculated from the time of first mount until last mount, was 771 +/- 98 min (range = 4 to 1,508 min). Mean number of mounts during estrus was 8.89 +/- 1.29 (range = 3 to 25 mounts). Length of estrus at the first short cycle did not differ from the length of the first fertile estrus between, or within, individuals. Estrous behavior was initiated more frequently during the night (2300 to 0500; P < 0.05). Bull introduction can be used as a simple, low-cost management tool for synchronizing estrus in farmed muskoxen. Radiotelemetry was an effective tool for identifying breeding behavior in this species.
Seasonal endocrine changes in 5 non-bred and 10 pregnant Alaskan reindeer have been documented. Blood samples were collected from early September until early May, spanning the breeding season, gestation, or the anovulatory period. Plasma was analyzed by RIA for progesterone (P4), estradiol-17beta, estrone, and estrone sulfate. Elevated P4 in 80% of the reindeer at the onset of the study indicated that ovarian activity had been initiated. The median date for the onset of the first recorded full-length ovulatory cycle was September 23. In nonbred reindeer, the mean ovulatory cycle length from September to May was 24 +/- 1 d (range 18 to 29 d). Nonbred females continued to cycle throughout the winter, displaying 6 to 8 ovulatory cycles after the beginning of blood sampling. Cycle length (mean 22 to 24 d) did not vary between individuals (P = 0.170) or over the course of the winter (P = 0.244). In early April, ovulatory cycles ceased with normal demise of the corpus luteum in 2 females, whereas the remaining 3 females formed apparently persistent corpora lutea. Natural service breeding occurred between September 10 and October 2, and P4 profiles indicated that all breeding females conceived to the first mating. Concentrations of P4 rose steadily after conception and remained elevated throughout gestation, with mean concentrations not varying significantly (P = 0.104) from 4 to 28 wk of gestation. Estrogens all followed patterns similar to each other, remaining at baseline concentrations until approximately 24 wk of gestation and rising coincidently as P4 declined just before parturition. There was a continual overlap throughout the winter in peak P4 concentrations observed in cycling and pregnant reindeer. Calving occurred between April 8 and May 2, resulting in a mean gestation length of 211 +/- 2.2 d (range 198 to 221 d). Information from this study can be used by Alaskan reindeer producers to improve management and profitability of reindeer production.
. 2007. Estrous synchronization and the male effect in captive muskoxen. Can. J. Anim. Sci. 87: 535-538. Bovine CIDR were used for 11 d to synchronize estrus in 18 farmed muskoxen. Nine muskoxen went into harem for 1 wk (BRED) following CIDR removal and nine animals served as treated, non-mated controls (CTL). Progestin treatment prevented short estrous cycles (100% BRED; 88.9% CTL). The interval from CIDR removal to CL formation was 7.2 d (BRED) and 11.6 d (CTL) and fertility rate at the estrus following treatment was 88.9% (BRED). The use of bovine CIDR to synchronize estrus reduced the harem period to 1 wk and resulted in synchronized calving (7 d) following a mean gestation of 246 d.
As a pilot intervention strategy to support undergraduate students, especially rural and Alaska Native students who are pursuing biomedical science research and career trajectories, we have developed a unique, mid-level Research, Advising, and Mentoring Professional (RAMP) position. In this article we outline the reasons for creating this position, RAMP qualifications, training, duties, and differences between RAMP and other positions typically found in higher education. Additionally, we discuss the evolution of the position and why it may be of interest to other institutions as they address similar issues involving students from underrepresented groups. Preliminary survey and focus group data from students mentored directly by RAMPs indicated that the holistic advising approach of RAMPs has had a positive impact on student experiences by supporting persistence in degree programs and providing psychosocial support of both personal and professional development.
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