Pregnancy rates and serum progesterone levels of polar bears in western Hudson Bay

1992 ◽  
Vol 70 (3) ◽  
pp. 561-566 ◽  
Author(s):  
Andrew E. Derocher ◽  
Ian Stirling ◽  
Dennis Andriashek
Keyword(s):  
Minimum Weight ◽  
Pregnancy Rates ◽  
Hudson Bay ◽  
Polar Bears ◽  
Age Classes ◽  
Serum Progesterone ◽  
Pregnant Females ◽  
Fat Stores ◽  
First Time ◽  
Old Females

Blood samples were collected from 354 female polar bears (Ursus maritimus) on 476 occasions between 1982 and 1990. Serum progesterone concentrations were determined to evaluate reproductive status. Progesterone levels greater than 2.5 ng/mL were considered indicative of pregnancy in autumn. Of 85 females classified as pregnant that were seen the following year, 67% were with cubs and 33% were without cubs. Possible explanations for the large proportion of females with apparent reproductive failure include neonatal mortality, failure to implant, or abortion. The minimum weight of a confirmed pregnant female in autumn was 189 kg, but approximately 10% of the suspected pregnant females were below this and may have had insufficient fat stores to fast through the winter and produce cubs. Based on progesterone levels, implantation appeared to occur between mid-September and mid-October, likely followed by parturition from mid-November to mid-December. The annual pregnancy rate of solitary females, as determined by progesterone concentrations, varied between 82.4 and 100%, but the differences were not significant. Females bred for the first time between 3 and 5 years of age, at an average of 4.1 years. The age-specific pregnancy rates of 3- to 4-year-old females and females 21 years and older were lower than those of other age-classes. However, some older females appear to retain reproductive competency throughout their life.

scholarly journals Evidence of adoption, monozygotic twinning, and low inbreeding rates in a large genetic pedigree of polar bears

2015 ◽  
Author(s):  
René M. Malenfant ◽  
David W. Coltman ◽  
Evan S. Richardson ◽  
Nicholas J. Lunn ◽  
Ian Stirling ◽  
...  
Keyword(s):  
Mating Systems ◽  
Parentage Analysis ◽  
Hudson Bay ◽  
Polar Bears ◽  
Nucleotide Polymorphisms ◽  
Single Nucleotide ◽  
Monozygotic Twinning ◽  
Close Relatives ◽  
Free Ranging ◽  
First Time

Multigenerational pedigrees have been developed for free-ranging populations of many species, are frequently used to describe mating systems, and are used in studies of quantitative genetics. Here, we document the development of a 4449-individual pedigree for the Western Hudson Bay subpopulation of polar bears (Ursus maritimus), created from relationships inferred from field and genetic data collected over six generations of bears sampled between 1966 and 2011. Microsatellite genotypes for 22-25 loci were obtained for 2945 individuals, and parentage analysis was performed using the program FRANZ, including additional offspring-dam associations known only from capture data. Parentage assignments for a subset of 859 individuals were confirmed using an independent medium-density set of single nucleotide polymorphisms. To account for unsampled males in our population, we performed half-sib/full-sib analysis to reconstruct males using the program COLONY, resulting in a final pedigree containing 2957 assigned maternities and 1861 assigned paternities with only one observed case of inbreeding between close relatives. During genotyping, we identified two independently captured two-year-old males with identical genotypes at all 25 loci, showing--for the first time--a case of monozygotic twinning among polar bears. In addition, we documented six new cases of cub adoption, which we attribute to cub misidentification or misdirected maternal care by a female bereaved of her young. Importantly, none of these adoptions could be attributed to reduced female vigilance caused by immobilization to facilitate scientific handling, as has previously been suggested.

Temporal variation in reproduction and body mass of polar bears in western Hudson Bay

1995 ◽  
Vol 73 (9) ◽  
pp. 1657-1665 ◽  
Author(s):  
Andrew E. Derocher ◽  
Ian Stirling
Keyword(s):  
Body Mass ◽  
Litter Production ◽  
Hudson Bay ◽  
Polar Bears ◽  
Age Classes ◽  
Study Recruitment ◽  
Term Variation ◽  
Long Term Trends ◽  
Western Hudson Bay

We studied annual and long-term variation in rates of reproduction in female polar bears (Ursus maritimus) in western Hudson Bay from 1966 to 1992. In addition, long-term trends in body mass were examined from 3146 captured polar bears. Reproduction rates declined in the late 1980s from higher levels in 1966–1984. Litter production decreased from 0.48 to 0.34 litters per female each year over the study. Recruitment to autumn declined from 0.75 to 0.52 cubs per female each year, in part because of cub mortality between spring and autumn, which increased from 25.0% in 1980–1984 to 50.9% in 1987–1992. Spring and autumn litter sizes of females with cubs did not vary annually, but litter sizes of females with yearlings varied between years. The proportion of yearlings independent of their mother in autumn dropped from 81% prior to 1980 to 34% in 1980–1992. After 1986, offspring remained with their mothers longer, resulting in the birth interval increasing from 2.1 to 2.9 years. Body mass of most age-classes of females and males declined in the 1980s. Unlike earlier studies that found reproduction rates to be higher in western Hudson Bay than in higher latitude populations, reproduction rates in 1986–1992 in western Hudson Bay were similar to those of other populations. Insufficient information was available to determine the cause of declines in reproduction and body mass.

The significance of supplemental food to polar bears during the ice-free period of Hudson Bay

1985 ◽  
Vol 63 (10) ◽  
pp. 2291-2297 ◽  
Author(s):  
N. J. Lunn ◽  
Ian Stirling
Keyword(s):  
Food Sources ◽  
Hudson Bay ◽  
Polar Bears ◽  
Adult Males ◽  
Blood Samples ◽  
Supplemental Food ◽  
Pregnant Females ◽  
Major Factors ◽  
Age And Sex ◽  
Family Groups

Polar bears were studied near Churchill, Manitoba, to evaluate the possible importance of supplemental food. Once ashore, bears became segregated by age and sex; family groups and pregnant females moved inland into a denning area, while single bears, especially adult males, remained along the coast. Bears were inactive and fed little. Analysis of blood samples taken from bears in the denning area suggested that they also were not feeding. By remaining inactive, they are able to minimize energetic demands and the chance of hyperthermia. After 2 months ashore, some bears, mainly family groups and subadults, fed in the Churchill dump. The data indicated that individual needs and learning were major factors determining which bears used the dump. Adult males did not feed there even though they may have been there previously as cubs or subadults. Bears which fed in the dump were significantly heavier than those which did not. There was no evidence that bears using the dump gained either reproductive or survival advantages. We conclude that polar bears will use supplemental food sources which are available or if they have previously learned their location; however, it is not necessary for their survival.

scholarly journals The value of serum progesterone level on day of human chorionic gonadotrophin administration / metaphase II oocyte ratio in predicting IVF/ICSI outcome in patients with normal ovarian reserve

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Ahmad Mahran ◽  
Mohammed Khairy ◽  
Reham Elkhateeb ◽  
Abdel Rahman Hegazy ◽  
Ayman Abdelmeged ◽  
...  
Keyword(s):  
Sensitivity And Specificity ◽  
Ovarian Response ◽  
Pregnancy Rates ◽  
Clinical Pregnancy ◽  
Progesterone Level ◽  
Receiver Operating Curve ◽  
Serum Progesterone ◽  
Predictive Values ◽  
Significant Difference ◽  
Assisted Reproduction Treatment

Abstract Background The clinical implication of the increased serum progesterone level on the day of HCG administration in assisted reproduction treatment (ART) is still controversial. The current study aimed to compare the predictive value of serum progesterone on day of HCG administration / metaphase II oocyte (P/MII) ratio on IVF/ ICSI outcome to serum progesterone (P) level alone and the ratio of serum progesterone/estradiol level (P/E2) ratio in prediction of pregnancy rates after ART. Material & methods Two hundred patients admitted to the IVF/ICSI program at Minia IVF center in Egypt in the period from October 2016 to May 2018 were included in this study. Serum Progesterone (P) and Estradiol (E2) levels were estimated on the day of HCG administration. The ratio between serum P and the number of MII oocytes (P/MII ratio) was calculated and the predictive values of the three parameters (P, P/E2 ratio and P/MII ratio) in prediction of cycle outcomes were measured. Results P/ MII oocyte ratio was significantly lower in patients who attained clinical pregnancy (n = 97) as compared with those who couldn’t whilst there was no significant difference in P and P/E2 ratio between the two groups. Using a cut off value of 0.125, the sensitivity and specificity of progesterone/ MII ratio in prediction of no pregnancy in IVF/ICSI were 75.7 and 77.1% respectively with the area under The Receiver operating curve (ROC-AUC) = 0.808. The respective values of the ROC-AUC for the P and P/E2 ratio were 0.651 and 0.712 with sensitivity and specificity of 71.2 and 73.5%for P level and of 72.5 and 75.3% for P/E2 ratio. Implantation or clinical pregnancy rates were significantly different between patients with high and low P/MII ratio irrespective of day of embryo transfer (day 3 or 5). Conclusions In patients with normal ovarian response, serum progesterone on day of HCG / MII oocyte ratio can be a useful predictor of pregnancy outcomes and in deciding on freezing of all embryos for later transfer instead of high progesterone level alone.

Sex steroids and their relationship to binding proteins in the serum of the marmoset monkey (Callithrix jacchus)

1983 ◽  
Vol 96 (3) ◽  
pp. 443-450 ◽  
Author(s):  
J. K. Hodges ◽  
S. A. K. Eastman ◽  
N. Jenkins
Keyword(s):  
Sex Steroids ◽  
Luteal Phase ◽  
Inverse Relationship ◽  
Equilibrium Dialysis ◽  
Sex Hormone Binding Globulin ◽  
Binding Properties ◽  
Serum Progesterone ◽  
Pregnant Females ◽  
Marmoset Monkey ◽  
Steroid Binding

A sex hormone binding globulin (SHBG) similar to human SHBG was identified in marmoset serum based on its gel electrophoretic mobility, isoelectric point and steroid binding properties. Levels of serum SHBG were measured in immature and mature males, immature females and females during the luteal phase and pregnancy; serum progesterone, 5α-dihydrotestosterone (5α-DHT), testosterone, oestradiol-17β and oestrone were also measured. Mean (± s.e.m.) concentrations of SHBG in immature males (336 ±19 nmol/l) were higher (P <0·01) than those in mature males (251 ±13 nmol/l), whereas values in the groups of females were similar (359 ± 12, 395 ± 17, 397 ± 39 nmol/l in immature, non-pregnant and pregnant females respectively). There was an inverse relationship between SHBG and the levels of testosterone (r= −0·67) and 5α-DHT (r = −0·86) in males, but the correlation was significant (P <0·05) only for 5α-DHT. There was no correlation between levels of SHBG and oestrogens in males or between levels of SHBG and any of the steroids measured in females. Equilibrium dialysis was used to assess the percentage of steroid in serum in the unbound form. Mean percentage values for unbound testosterone and 5α-DHT were lower in immature males than in mature males (P <0·01) and negatively correlated with levels of SHBG (r = −0·78, testosterone; r = −0·56, 5α-DHT).

New Complexities in Zoogeography and Taxonomy of the Pygmy Whitefish (Prosopium coulteri)

1972 ◽  
Vol 29 (12) ◽  
pp. 1772-1775 ◽  
Author(s):  
C. C. Lindsey ◽  
W. G. Franzin
Keyword(s):  
River System ◽  
Yukon Territory ◽  
Hudson Bay ◽  
The South ◽  
Bristol Bay ◽  
River Drainage ◽  
Bay Area ◽  
First Time ◽  
Mackenzie River

Pygmy whitefish (Prosopium coulteri) are recorded for the first time from the Peel–Mackenzie river drainage (Elliott Lake, Yukon Territory) and from the Hudson Bay drainage (Waterton Lakes, Alberta, in the South Saskatchewan–Nelson river system). The morphology of specimens from both localities contradicts the previously known pattern of a southeastern "low-rakered" and a northwestern "high-rakered" form (with the two forms occurring sympatrically in some lakes of the Bristol Bay area). Specimens from Elliott Lake, the most northerly known locality, resemble the southeastern form and those from Waterton Lakes the northwestern form. Both Waterton and Elliott lakes lie close to unglaciated refugia, suggesting that the species may have survived Wisconsin glaciation and diverged in several different watersheds.

Concentrations of legacy and new contaminants are related to metabolite profiles in Hudson Bay polar bears

2019 ◽  
Vol 168 ◽  
pp. 364-374 ◽  
Author(s):  
A.D. Morris ◽  
R.J. Letcher ◽  
M. Dyck ◽  
B. Chandramouli ◽  
J. Cosgrove
Keyword(s):  
Hudson Bay ◽  
Polar Bears ◽  
Metabolite Profiles

scholarly journals The Effect of A PRID®Delta-Based Estrus Synchronization Protocol On Pregnancy Rates In Cows With No Estrus Symptoms

2022 ◽  
Author(s):  
Murat Can Demir ◽  
Cihan Kaçar ◽  
Umut Çağın Arı ◽  
Semra Kaya ◽  
Oğuz Merhan ◽  
...  
Keyword(s):  
Pregnancy Rate ◽  
Artificial Insemination ◽  
Prostaglandin F2α ◽  
Pregnancy Rates ◽  
Dominant Follicle ◽  
Serum Progesterone ◽  
Blood Samples ◽  
Follicle Diameter ◽  
Follicle Size ◽  
Equine Chorionic Gonadotropin

Abstract The present study aimed to determine the effects of progesterone-based gonadotropin-releasing hormone (GnRH), prostaglandin F2α (PGF2α), and equine chorionic gonadotropin (eCG) injections on progesterone profiles and pregnancy rates in cows with no estrus symptoms within 60 days after parturition. A total of 80 cows were included in the study. All animals had the progesterone-releasing device PRID®Delta placed intravaginally for nine days with an injection of GnRH. On the eighth day, PGF2α was injected, and PRID®Delta was removed from the vagina on day nine. Artificial insemination was carried out 60 hours after PRID®Delta removal. In half of the animals (n = 40), 600 IU of eCG was injected when PRID®Delta was removed on the ninth day before artificial insemination 60 hours later. Blood samples were taken from the tail vein on days 0 and 8 to determine progesterone levels. The pregnancy rate in the group that received eCG was 37.5%, while it was 27.5% in those that did not (P = 0.4). While the dominant follicle diameter was 15.5 mm in cows injected with eCG during timed artificial insemination, the follicle diameter was 12.4 mm in cows with no eCG injection (P <0.001). There were no differences in serum progesterone values in blood samples taken until the time of artificial insemination. However, progesterone values in the blood taken during artificial insemination were 0.94 ng/ml in the eCG- group and 0.72 ng/ml in the eCG+ group (P <0.05). As a result, it was determined that eCG injections, in addition to progesterone-based GnRH and PGF2α applications, increased the pregnancy rates in cows without symptoms of estrus. The dominant follicle diameter was larger in cows treated with eCG during artificial insemination; however, follicle size did not increase the pregnancy rate.

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