Abstract: Adult male elephants periodically show the phenomenon of musth, a condition associated with increased aggressiveness, restlessness, significant weight reduction and markedly elevated androgen levels. It has been suggested that musth-related behaviours are costly and that therefore musth may represent a form of physiological stress. In order to provide data on this largely unanswered question, the first aim of this study was to evaluate different assays for non-invasive assessment of adrenocortical function in the male African elephant by (i) characterizing the metabolism and excretion of [3H]cortisol (3H-C) and [14C]testosterone (14C-T) and (ii) using this information to evaluate the specificity of four antibodies for determination of excreted cortisol metabolites, particularly with respect to possible cross-reactions with androgen metabolites, and to assess their biological validity using an ACTH challenge test. Based on the methodology established, the second objective was to provide data on fecal cortisol metabolite concentrations in bulls during the musth and non-musth condition. 3H-C (1 mCi) and 14C-T (100 microCi) were injected simultaneously into a 16 year old male and all urine and feces collected for 30 and 86 h, respectively. The majority (82%) of cortisol metabolites was excreted into the urine, whereas testosterone metabolites were mainly (57%) excreted into the feces. Almost all radioactive metabolites recovered from urine were conjugated (86% 3H-C and 97% 14C-T). In contrast, 86% and >99% of the 3H-C and 14C-T metabolites recovered from feces consisted of unconjugated forms. HPLC separations indicated the presence of various metabolites of cortisol in both urine and feces, with cortisol being abundant in hydrolysed urine, but virtually absent in feces. Although all antibodies measured substantial amounts of immunoreactivity after HPLC separation of peak radioactive samples and detected an increase in glucocorticoid output following the ACTH challenge, only two (in feces against 3alpha,11-oxo-cortisol metabolites, measured by an 11-oxo-etiocholanolone-EIA and in urine against cortisol, measured by a cortisol-EIA) did not show substantial cross-reactivity with excreted 14C-T metabolites and could provide an acceptable degree of specificity for reliable assessment of glucocorticoid output from urine and feces. Based on these findings, concentrations of immunoreactive 3alpha,11-oxo-cortisol metabolites were determined in weekly fecal samples collected from four adult bulls over periods of 11-20 months to examine whether musth is associated with increased adrenal activity. Results showed that in each male levels of these cortisol metabolites were not elevated during periods of musth, suggesting that in the African elephant musth is generally not associated with marked elevations in glucocorticoid output. Given the complex nature of musth and the variety of factors that are likely to influence its manifestation, it is clear, however, that further studies, particularly on free-ranging animals, are needed before a possible relationship between musth and adrenal function can be resolved. This study also clearly illustrates the potential problems associated with cross-reacting metabolites of gonadal steroids in EIAs measuring glucocorticoid metabolites. This has to be taken into account when selecting assays and interpreting results of glucocorticoid metabolite analysis, not only for studies in the elephant but also in other species.

Abstract: In this study, we investigated endocrine factors and behaviour in free-living Common hamsters (Cricetus cricetus) during reproductive and non-reproductive periods of the annual cycle. We applied a non-invasive method to gain information on seasonal changes in adrenocortical activity in male and female hamsters by analysing faecal glucocorticoid metabolite concentrations (FCM). In addition, plasma progesterone concentrations were monitored in females throughout the non-hibernation season. The animals were live-trapped from spring emergence until the onset of hibernation in autumn. Reproductive status was determined at capture and blood and faecal samples were collected. During behavioural observations, agonistic and sexual interactions were recorded. FCM concentrations were significantly higher in males than in females during the reproductive period. In males, a pronounced increase in FCM during the reproductive period coincided with high frequencies of intrasexual aggression. In females, FCM levels remained relatively constant. Aggressive behaviour in females increased during the reproductive period, but was much less frequent than in males. Females, which successfully raised a second litter after a postpartum oestrus and concurrent lactation and gestation had lower FCM levels than individuals, which lost their second litter after parturition. As expected, plasma progesterone concentrations were low before and after the reproductive period. During gestation, levels peaked and remained elevated during lactation. The results of this field study provide insight in critical periods associated with reproduction in male and female Common hamsters.

Abstract: Horses, like other ungulates, are active in the day, at dusk, dawn, and night; and, they have eyes designed to have both high sensitivity for vision in dim light and good visual acuity under higher light levels (Walls, 1942). Typically, daytime activity is associated with the presence of multiple cone classes and color-vision capacity (Jacobs, 1993). Previous studies in other ungulates, such as pigs, goats, cows, sheep and deer, have shown that they have two spectrally different cone types, and hence, at least the photopigment basis for dichromatic color vision (Neitz & Jacobs, 1989; Jacobs, Deegan II, Neitz, Murphy, Miller, & Marchinton, 1994; Jacobs, Deegan II, & Neitz, 1998). Here, electroretinogram flicker photometry was used to measure the spectral sensitivities of the cones in the domestic horse (Equus caballus). Two distinct spectral mechanisms were identified and are consistent with the presence of a short-wavelength-sensitive (S) and a middle-to-long-wavelength-sensitive (M/L) cone. The spectral sensitivity of the S cone was estimated to have a peak of 428 nm, while the M/L cone had a peak of 539 nm. These two cone types would provide the basis for dichromatic color vision consistent with recent results from behavioral testing of horses (Macuda & Timney, 1999; Macuda & Timney, 2000; Timney & Macuda, 2001). The spectral peak of the M/L cone photopigment measured here, in vivo, is similar to that obtained when the gene was sequenced, cloned, and expressed in vitro (Yokoyama & Radlwimmer, 1999). Of the ungulates that have been studied to date, all have the photopigment basis for dichromatic color vision; however, they differ considerably from one another in the spectral tuning of their cone pigments. These differences may represent adaptations to the different visual requirements of different species.

Abstract: A procedure is described for determining salivary cortisol levels by a competitive protein-binding assay using horse transcortin. The collection of saliva was performed by means of filter paper-strips. Filter paper samples are more than 5 days stable after air-drying. In this form, the samples could be stored without refrigerator or deep-freezer and, if necessary, sent by post to the laboratory without any special precaution. Stressful situation of either painful or anxious origin were associated with an adequate increase of salivary cortisol levels. The increases were 157 to 230% of the initial or normal values dependent on the kind of stress. The mean values in 4 cases of Cushing's syndrome were 380% and 1 hour after 25 I.U. ACTH 690% higher than those in normal persons. In normal persons, a well-defined circadian rhythm has been observed.

Abstract: The purpose of this study was to evaluate the effects of speed and slope on the activity of trunk muscles. The electromyographic (EMG) activity of the splenius (Sp), longissimus dorsi (LD) and rectus abdominis (RA) muscles was recorded with surface electrodes during treadmill locomotion at trot for different combinations of speed (3.5 to 6 m/s) and slope (0 to 6%). Raw EMG signals were processed to determine activity duration, onset and end and integrated EMG (IEMG). For the 3 muscles investigated, onset and end of activity were obtained earlier in the stride cycle when speed increased. A longer duration of activity for the LD, a shorter duration for the RA and an unchanged duration for the Sp were also observed. The IEMG of the latter was poorly affected by speed, whereas it increased linearly with speed for the 2 other muscles. When treadmill inclination changed from 0 to 6%, EMG activity of the LD and RA began and ended later; a longer activity duration was noted. Temporal parameters for Sp did not change with slope. A significant and progressive increase in the IEMG of the 3 muscles was observed with increasing slope. This evaluation of the activity of trunk muscles provides objective data for the use of speed or slope in training programmes.