Janice E. Rowell

Seasonal levels of metabolic hormones and substrates in male and female reindeer (Rangifer tarandus).

Seasonal levels of cortisol, growth hormone (GH), insulin like growth factor 1 (IGF-1), glucose, triiodothyronine (T3), free T3, thyroxine and free fatty acids (FFA) were measured every 3 weeks for 54 weeks in the plasma of five adult bulls, and four barren and five pregnant Alaskan reindeer (Rangifer tarandus) cows. Three consecutive samples were taken from each animal. Cortisol levels exhibited wide seasonal variation (9-45 ng/ml) [corrected] without any peak or difference in levels among groups. Rising levels were detected between the 3 consequent samples. Peak GH levels, detected during January and February, were higher in the non-pregnant group (54 ng/ml) than the pregnant (26 ng ml-1) and the male (27 ng ml-1) groups. Low GH levels (2-10 ng ml-1) were recorded between May and September. IGF-1 reached peak levels (715 ng ml-1) in males in August, in non-pregnant females in September (677 ng ml-1), and in the pregnant females in October (505 ng ml-1). Seasonal minima (404 in males, 172 and 93 in pregnant and non-pregnant groups) were detected in February. Glucose was fairly stable throughout the year (100-200 mg/100 ml). A rising levels were found between the three consecutive samples. Triiodothyronine (T3) (2.16-2.30 ng ml-1) peaked in all three groups during the spring and early summer, and minimal levels (0.61-0.97 ng ml-1) were detected from October to January. Conversely, thyroxine or free T3 did not exhibit seasonal variation. FFA fluctuated widely (97-1076 nmol l-1) throughout the year. Only in pregnant females were concentrations more stable (150-460 nmol l-1). Perhaps, because of ad libitum supply of food in captive reindeer, only T3 and GH exhibited pronounced seasonal fluctuations which could be related to the metabolic changes expected during the annual cycle.

Seasonal Levels of Reproductive Hormones and Their Relationship to the Antler Cycle of Male and Female Reindeer (Rangifer tarandus)

Seasonal levels of LH, FSH, testosterone (T), estradiol, progesterone (P), and prolactin (PRL) were determined in the plasma of five adult bulls, and five barren and four pregnant cows of Alaskan reindeer (Rangifer tarandus), which were sampled every 3 weeks for 54 weeks. The male reproductive axis was sequentially activated; LH peaked in May-June (2 ng/ml), FSH in June (51 ng/ml), and T in September (11.8 ng/ml). LH levels in females reached a maximum in both groups at the end of August (the beginning of the rut). Seasonal variation in FSH was minimal in pregnant cows, but exhibited one elevation (41 ng/ml) in barren ones in November. T levels in cows remained at barely detectable levels. The decrease of T values observed in both groups in December and March was not significant. PRL peaked in May in cows (135 ng/ml pregnant, 140 ng/ml non-pregnant) and in June in bulls (92 ng/ml). Estradiol was highest in bulls in the rut (August), in non-pregnant cows in January and in pregnant cows in April, shortly before parturition. P levels in the pregnant cows rose from September and peaked (9 ng/ml) shortly before parturition in April. In the non-pregnant females P values increased and decreased several times before peaking (5 ng/ml) in March. In the males, the variation of T and estradiol levels correlated relatively well with the antler cycle but in the females the variation of neither estradiol, progesterone nor T appeared to be related to mineralization or casting of antlers.

Reindeer bull introduction affects the onset of the breeding season

Reindeer are seasonally polyestrus, short day breeders, with estrous cycles of approximately 20 days in length. The objective of this study was to investigate the effects of reindeer bull exposure on the onset of the reindeer cow breeding season and to investigate whether cows with calving experience responded differently than cows with no previous reproductive experience. During year 1, blood samples were collected weekly beginning 14 July and continuing until 15 September (n = 8) or 30 September (n = 8) in order to determine the onset of the breeding season, based on ovarian function, with no bull present. Plasma was stored frozen for later assay of progesterone (P(4)) following the conclusion of sample collection. Eight randomly selected cows were allowed to breed with a bull during year 1. The mean onset of ovarian activity in the first year was 15 September (range: 8-29 September). The bull was removed from cows more than 2 months prior to the start of the experimental period during year 2 and housed at a separate facility approximately 2 km distant. Blood samples were collected during year 2 from 14 cows 3x weekly beginning on 11 August (day 1) and continuing until 29 September (day 50) and plasma was stored frozen for later assay of P(4) following the conclusion of sample collection. On day 6, cows were divided into two groups such that group 1 (early bull exposure; EBE), consisted of four cows that had calved the previous spring and four cows that had no reproductive experience (n = 8). Group 2 (late bull exposure; LBE), consisted of three cows that had calved the previous spring and three cows that had no reproductive experience (n = 6). EBE experienced bull introduction on day 13, 23 days earlier than the average onset of ovarian activity during year 1. LBE experienced bull introduction on day 46, 10 days later than the average onset of ovarian activity during year 1. Progesterone concentrations were analyzed by ANOVA procedures for repeated measures. Bull presence was not requisite for the onset of ovarian activity during either year. Previous reproductive status had no effect on the onset of ovarian activity within EBE (P = 0.61) or within LBE (P = 0.92). Time of bull introduction had a significant effect on the onset of ovarian activity when EBE was compared to LBE (P<0.001). The first sustained increase in mean P(4) concentration above 1 ng/ml occurred on day 25 in EBE reindeer and day 41 in LBE reindeer. EBE reindeer initiated ovarian activity 12 days after bull introduction while LBE reindeer initiated ovarian activity 5 days before bull introduction. All cows penned with the bull conceived during both breeding seasons, demonstrated by production of live calves during the subsequent spring. Cows bred during year 1 all calved within a 9 day-period. During year 2, EBE displayed a more synchronous calving period compared to LBE (P<0.05). Results indicate that bull management affects the onset of the breeding season in reindeer cows, regardless of previous reproductive experience.

Odor of the muskox : A preliminary investigation.

The behavior of captive male muskoxen was observed closely during their characteristic superiority display, the anatomy of the preputial region was studied in two adults and three calves, and preputial washings and preorbital gland secretion were subjected to gas chromatography and mass spectroscopy. During the superiority display, the prepuce was everted to form a pendulous tube tipped with a fringe of matted hair. Owing to the movement of the animal, the urine that dribbled from the preputial opening was liberally applied to the long guard hairs of the belly. The superiority display was almost exclusively confined to dominant males and apparently accounted for their odor. In the quiescent state, the hair seen around the preputial opening was drawn inside and formed an 8 cm-wide band on the lining of the prepuce. The preputial washings contained large amounts of benzoic acid andp-cresol. The infraorbital gland secretion contained cholesterol, benzaldehyde, and a homologous series of saturated γ-lactones ranging from 8 to 12 carbons. The latter compounds and the natural secretion smell similar to the human nose.

Pregnancy-Specific Protein in the Plasma of Captive Muskoxen

We collected plasma samples from 6 captive muskoxen (Ovibos moschatus) before breeding and throughout gestation and tested them for the antigen that cross-reacts with antiserum to bovine pregnancyspecific protein B (PSPB). Presence of the antigen in muskoxen provided a reliable method for detecting pregnancy. It was detected in all muskoxen by 24 days of pregnancy but was not found in non-pregnant females or castrate controls. J. WILDL. MANAGE. 53(4):899-901 Accurate detection of pregnancy in free-living mammals is important to wildlife managers (Houston et al. 1986), but techniques developed for domestic species often prove impractical and costly when applied to field situations. This is particularly true of muskoxen, a species widely dispersed in an inhospitable environment. Blood samples collected during immobilization could provide the most practical means for pregnancy detection. Analysis of serum for progesterone has been used for pregnancy detection in a number of wild ungulates (Wood et al. 1986), but the technique requires knowledge of the threshold level for pregnancy determination (Wood et al. 1986) and breeding dates, or several blood samples taken at specified intervals (Sasser and Ruder 1987). Muskoxen are seasonally polyestrus and may normally cycle at least until the end of October (Rowell et al. 1987). Progesterone levels during the first 80 days of pregnancy are indistinguishable from those of the luteal phase (Rowell and Flood 1986), making a single progesterone value, collected during the fall or winter, particularly difficult to interpret. The ability to identify a pregnancy-specific protein in serum would alleviate these problems. Pregnancy-specific protein B has been isolated from bovine extra-embryonic membranes (Butler et al. 1982); it is produced in the binucleate cells of the bovine placenta (Eckblad et al. 1985, Reimers et al. 1985) and a double antibody radioimmunoassay (RIA) has been developed for its detection in bovine serum (Sasser et al. 1986). Pregnancy-specific antigens that cross-react in the RIA for bovine PSPB have been identified in sera from domestic sheep (Ruder et al. 1988), elk (Cervus elaphus) (Sasser et al. 1985), mule (Odocoileus hemionus) and white-tailed deer (0. virginianus) (Wood et al. 1986), and mountain goats (Oreamnos americanus) (Houston et al. 1986). Our study was undertaken to determine if muskox plasma contained antigens that crossreacted with antiserum to bovine PSPB, assess the validity of PSPB assay for pregnancy diagnosis in muskoxen, and assess how soon after conception a positive reaction to PSPB could be detected. The captive muskox herd was established through a grant from the Donner Canadian Foundation and is currently supported by the Natural Sciences and Engineering Research Council of Canada, Operating Grant A2759 and Infrastructure Grant A2793. We thank Colleen Stevens for her excellent care of the animals and invaluable assistance with the study. Support for assay development and use was provided by the Idaho Agricultural Experiment Station.

Canadian Muskoxen in Central Europe - A Zoo Veterinary Review

This paper summarizes 29 years of veterinary experience maintaining a herd of muskoxen at the Tierpark Berlin-Friedrichsfelde, Berlin, Germany. The transplanted muskoxen acclimated to the zoo enviroment without fatalities. However, a few striking changes were seen. They exhibit a high sensitivity to sudden changes in weather conditions (especially falling atmospheric pressure); there is a tendency for their qiviut to become sparser with time; rutting and subsequent calving occur later than in their native habitat. Details of medical conditions in both calves and adults ate given along with information on hematology and immobilization.

Scent marking by male caribou: an experimental test of rubbing behavior

We studied scent marking by adult male caribou (Rangifer tarandus) during rut in September 1998 at the Large Animal Research Station in Fairbanks, Alaska, USA. We used an experimental approach involving two captive groups of two males each to test for effects of social status, tree size, texture, and scent on rubbing behavior by caribou. Dominant males did not rub more often or for a longer duration than subordinates. Caribou rubbed trees with smaller diameters more often than large-diameter trees. Males preferred trees with bark for rubbing to those trees with their bark removed prior to the experiment. Caribou exhibited no preference for posts with pine-oil applied compared with posts without that aromatic scent. We hypothesize that rubbing of trees by male caribou is related to synchronization or priming of estrus in females, but more research is needed to test that potential function of scent marking.

Progesterone during the breeding season and pregnancy in female muskoxen on different dietary regimens

Previously, we documented lowered calving success in captive muskoxen raised for 6 years on a low nutritional plane. In an effort to identify causes of lowered calf production, we looked at serum progesterone during the breeding season in muskoxen raised on either a high (HP) or low (LP) nutritional plane. Complete cessation of estrous cycli-city in 2 parous cows was the only irregularity identified. Abortion and/or embryonic loss occurred in both HP and LP cows. We also compared progesterone during pregnancy between the 2 nutritional planes and lactating and non-lacta-ting cows. The timing of the rise and fall of the mid-pregnant progesterone peak was consistent with stage of gestation and apparently independent of time of breeding, diet or lactational status.

Estrous synchronization and the male effect in captive muskoxen

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. Key words: CIDR, Estrous synchronization, male effect, muskoxen, Ovibos moschatus

Population structure and dynamics in captive muskoxen at the Large Animal Research Station, 1988-1994

The muskox colony at the Large Animal Research Station, started in 1979, totaled 22 individuals before calving in 1988. Between 1988 -1994 cows of breeding age have been maintained on either a high plane (HP) or low plane (LP) of nutrition, and as far as possible, female offspring are kept with their mothers group. During this time the population has increased from 22 to 43 animals (25 females and 18 males). Fifty-four calves were born with an overall sex ratio of 52:48 (male:female). When partitioned between the 2 nutritional planes the sex ratio was HP 45:55 and LP 62:38. The calf/cow ratio was 0.83 in 1988 and 0.86 in 1994. The LP group accounted for most of the variability in pregnancy rate, primarily through delayed puberty and breeding pauses. Calf mortality was due mainly to abortions, stillbirths and neonatal death (n=12), 7 deaths occurred between 2 weeks and 1 year of age. All stillbirths and abortions (n=4) and 6 of 8 neonatal deaths affected calves of HP cows. Thirteen adults died, 4 males were loaned to other facilities and 2 new calves were added.