scholarly journals Efficacy of calf:cow ratios for estimating calf production of arctic caribou

Rangifer ◽  
2013 ◽  
pp. 27-34
Author(s):  
Raymond D. Cameron ◽  
Brad Griffith ◽  
Lincoln S. Parrett ◽  
Robert G. White
Keyword(s):  
Rangifer Tarandus ◽  
Survival Rates ◽  
Age Distribution ◽  
Calf Survival ◽  
Calculated Ratio ◽  
Unbiased Estimates ◽  
Deterministic Simulations ◽  
Biased Estimators ◽  
Sexually Mature ◽  
Old Females

Caribou (Rangifer tarandus granti) calf:cow ratios (CCR) computed from composition counts obtained on arctic calving grounds are biased estimators of net calf production (NCP, the product of parturition rate and early calf survival) for sexually-mature females. Sexually-immature 2-year-old females, which are indistinguishable from sexually-mature females without calves, are included in the denominator, thereby biasing the calculated ratio low. This underestimate increases with the proportion of 2-year-old females in the population. We estimated the magnitude of this error with deterministic simulations under three scenarios of calf and yearling annual survival (respectively: low, 60 and 70%; medium, 70 and 80%; high, 80 and 90%) for five levels of unbiased NCP: 20, 40, 60, 80, and 100%. We assumed a survival rate of 90% for both 2-year-old and mature females. For each NCP, we computed numbers of 2-year-old females surviving annually and increased the denominator of CCR accordingly. We then calculated a series of hypothetical “observed” CCRs, which stabilized during the last 6 years of the simulations, and documented the degree to which each 6-year mean CCR differed from the corresponding NCP. For the three calf and yearling survival scenarios, proportional underestimates of NCP by CCR ranged 0.046–0.156, 0.058–0.187, and 0.071–0.216, respectively. Unfortunately, because parturition and survival rates are typically variable (i.e., age distribution is unstable), the magnitude of the error is not predictable without substantial supporting information. We recommend maintaining a sufficient sample of known-age radiocollared females in each herd and implementing a regular relocation schedule during the calving period to obtain unbiased estimates of both parturition rate and NCP.

Displacement and dispersion of parturient caribou at calving as antipredator tactics

1987 ◽  
Vol 65 (7) ◽  
pp. 1597-1606 ◽  
Author(s):  
A. T. Bergerud ◽  
R. E. Page
Keyword(s):  
Snow Cover ◽  
Rangifer Tarandus ◽  
Forest Cover ◽  
Ursus Arctos ◽  
Early Years ◽  
Stochastic Variation ◽  
Spring Phenology ◽  
Calf Survival ◽  
Searching Ability ◽  
High Elevations

Survival of caribou (Rangifer tarandus) calves until 4 months of age was monitored for 8 years in four herds in northern British Columbia, Canada. The chief cause of mortality was predation by wolves (Canis lupus) and grizzly bears (Ursus arctos) and this mortality was correlated within years between all herds. More calves died in years with late springs when extensive snow patches remained during calving in June than in early springs when larger snow-free areas existed. Before calving and after birth, caribou cows sought to space themselves out on snow-free areas in small aggregations at high elevations above treeline. By placing themselves at high elevations, the females increased the distance between themselves and wolves and bears travelling in the valley bottoms, as well as the main alternate prey, moose (Alces alces), which calved only in forest cover at lower elevations. In addition, the reduced snow in early springs meant that there was more space for dispersion. The variation in calf survival for three herds was negatively correlated with the heterogeneity of the calving area. Snow cover disappeared in smaller patches in more rugged mountains regardless of spring phenology, thereby providing a more constant search area for predators from year to year. More uniform mountains had either extensive areas of snow cover (late years) or brown substrates (early years), thus greatly varying the space that predators had to search between years. As stochastic variation in snow cover at calving time alters the searching ability of predators, the aggregation responses of prey, and the spatial overlap between predators and prey, it promotes short-term stability of the prey and lessens the probability of extinction.

The age distribution in the Taimyr population wild northern deer (Rangifer Tarandus) in the first decades of 21 centuries

2021 ◽  
pp. 15-21
Author(s):  
A. Shapkin ◽  
R. Ivanova ◽  
N. Arsentseva ◽  
N. Sukhanova
Keyword(s):  
Age Structure ◽  
Rangifer Tarandus ◽  
Age Distribution ◽  
Age Groups ◽  
Base Material ◽  
Middle Level ◽  
Reproduction Rate ◽  
Male And Female ◽  
Field Samples ◽  
Wild Deer

Objective: mathematical demography means to identify and evaluate the age distribution of male and female of Taimyr tundra reindeer in the first decade of the XXI century and future trends in demographic situation Taimyr population.Materials and methods. The base material for evaluating the current state of the population age structure Taimyr steel fishing representative sample of male and female wild deer (n = 10845 individuals) collected in the West, Central and Taimyr Putorana in 2001-2008., And the deer samples (n = 1569 individuals), the floor of which is unknown. Determination of individual animals from age and older (n = 9773 individuals) performed on histological sections of cutters according to the corresponding procedure. To repay the random deviations of sample data because of a lack of presence of immature animals (calves, yearlings, young 1-2 years) (selectivity of fishing is directed primarily at the production of individuals older than 3 years, why animals in different age groups in the samples is greater than there are in the population) applies a smoothing procedure. Then, positive deviation of the number of individuals in the same age group were leveled due to negative deviations in adjacent groups.Results. By smoothed age ranges of the field samples from 2001-2008 the current age distribution of Taimyr wild reindeer calculated and analyzed. The study showed that the theoretical current age distribution of males with realized breeding is 77.03, females - 80.56, in the combined groups of animals - 82.35%. The real population has 18-19 age generations of males and females. The reproductive core of males from 3 to 10 years old is 48.43%, individuals of age limit 11 years and older occupy 1.96% of this sex and age structure, calves and young animals for 1-2 years - 24.64%. For the reproductive part of females aged 3–15 years, the overall age distribution is 55.34%, and the proportion of juveniles and young animals, according to calculations, is determined in this part of the population at 25.16%. In the combined current age distribution, males, females: calves and young animals accounted for 27.72%, the sexually mature part with animals of older and age-specific ages - 54.63%.Conclusion. Demographic Taimir population modeling operation in the first decade of the XXI century long materials commercial samples collected at commercial points shown at current age distribution of the realized and reproduction conditions for existing commercial load males - 77.03 for females - 80.56 and for unified groups (males, females) - 82.4%. Meanwhile, the steady state and stable age distribution Taimyr tundra wild deer can reach a middle-level only when the fecundity of female reproductive generations with clean reproduction rate (R0) equal in population groupings 1.0

A study of breeding in grey kangaroos, Macropus giganteus Shaw and M. fuliginosus (Desmarest), in central New South Wales

1973 ◽  
Vol 21 (2) ◽  
pp. 183 ◽  
Author(s):  
WE Poole
Keyword(s):  
Mortality Rate ◽  
New South ◽  
Sympatric Species ◽  
Significant Excess ◽  
South Wales ◽  
Grey Kangaroo ◽  
Group A ◽  
Age Range ◽  
Sexually Mature ◽  
Old Females

A total of 2750 grey kangaroos were examined at Mt. Hope, N.S.W., over a period of 4 years, commencing in 1962. Two colour phases of grey kangaroo were recognized but it was not until late in the study that concurrent investigations revealed that two sympatric species occurred in the area in the approximate ratio 1 : 8. As it was not possible to distinguish the species accurately in retrospect, all the kangaroos were treated as one group. A few males became sexually mature at 20 months of age, most by 36 months, and all before they were 72 months old. Females generally became sexually mature when between 20 and 36 months of age but onset of breeding was dependent on the breeding season (September-March). Most females were breeding by their second summer, some by the third summer, and a few not until the fourth summer. Most births occurred between September and March but some occurred in all months of the year. Of the total females carrying pouch young, 5% had dormant embryos in the uterus and all of these had pouch young more than 180 days old. The highest per- centage of females carrying dormant embryos was found in late autumn, possibly because of improved nutrition after heavy rains. No western grey kangaroos apparently carried a dormant embryo but 30% of the total eastern grey females did. A significant excess of pouch young were attached to an anterior rather than a posterior teat in multiparous females. When an anterior teat was already being suckled by a young-at-foot, the posterior teat on the same side was apparently shielded and a significant excess of young born to such females attached to the anterior teat on the non-suckled side. If a posterior teat was enlarged, almost two-thirds of the newborn young attached to anterior teats; the greater number on the non-suckled side. One female had two young in the pouch, separated in age by the length of one gestation period, indicating that suckling by the first young had failed to inhibit the next expected ovulation. Disparity between 713 male and female young was not significant at 105: 100 for pouch young and 84: 100 for young-at-foot. For sets of pouch young through the age range 113-280 days there was an estimated constant mortality rate of 1.82% per 28 days. No between-sex or between season variation in the mortality rate was revealed.

Calving performance and calf survival in a twin-calving beef herd

1990 ◽  
Vol 1990 ◽  
pp. 1-1
Author(s):  
M.G. Diskin ◽  
T.G. McEvoy ◽  
J.M. Sreenan
Keyword(s):  
Litter Size ◽  
Survival Rates ◽  
Reproductive Rate ◽  
Beef Production ◽  
Total Cost ◽  
Calf Survival ◽  
Beef Herd ◽  
Low Efficiency ◽  
High Level ◽  
Calving Performance

In suckler beef production it is estimated that 55% of the total cost is required to maintain and replace the breeding females while only 1095 of total feed energy intake is stored in the tissue of the calves and cows. The low reproductive rate of the cow is primarily responsible for this low efficiency. Even in a well managed herd, weaning rate Is about 0.95 calves per cow per annum or less. It Is frequently hypothesised that increasing litter size by inducing twin calving would increase output, biological and economic efficiency provided few extra Inputs were required. Although twinning may increase the efficiency of beef production, spontaneous twin-calving is frequently associated with an Increased incidence of calving problems, poor calf survival, retained placentae and longer rebreeding intervals. Such problems related to twin-calving cannot be studied unless the frequency of twinning is increased above the levels that occur spontaneously. Embryo transfer can be used to Increase the frequency of twin calving thus allowing a better assessment of the potential to Increase output. A suckler herd, with a high level of twinning, was established to determine the effects of litter size on calving performance and calf survival rates.

Mortalities of the larvae of the Anopheles gambiae Giles complex and detection of predators by the precipitin test

1973 ◽  
Vol 62 (3) ◽  
pp. 359-369 ◽  
Author(s):  
M. W. Service
Keyword(s):  
Anopheles Gambiae ◽  
High Mortality ◽  
Survival Rates ◽  
Age Distribution ◽  
Fourth Instar ◽  
Immature Stages ◽  
Complex Species ◽  
Precipitin Test ◽  
Anopheles Gambiae Giles ◽  
Time Specific

Larval populations of the Anopheles gambiae Giles complex (species A and B) were sampled in Kenya, and from the frequencies of the age distribution of the immature stages time-specific life-tables were constructed. Daily survival rates and instar mortalities showed that there was high mortality amongst fourth-instar larvae, due at least in part to infections of larval nematodes, Coelomomyces and epibionts. Antiserum to the A. gambiae complex was prepared in rabbits so that the precipitin test could be employed to detect the presence of A. gambiae in gut smears taken from possible predators. By this serological technique various spiders, Diptera, Coleoptera and amphibia were identified as predators. These may be very important in regulating populations of A. gambiae even in small collections of water.

Moose (Alces alces) calf survival rates in the presence of wolves (Canis lupus) in southeast Norway

2012 ◽  
Vol 58 (5) ◽  
pp. 863-868 ◽  
Author(s):  
Therese Ramberg Sivertsen ◽  
Atle Mysterud ◽  
Hege Gundersen
Keyword(s):  
Canis Lupus ◽  
Alces Alces ◽  
Survival Rates ◽  
Calf Survival

scholarly journals Forecast of the Number of Doctorate Holders in Russia

2019 ◽  
Vol 29 (4) ◽  
pp. 510-528
Author(s):  
Valery A. Gurtov ◽  
Liudmila V. Shchegoleva ◽  
Sergey I. Pakhomov
Keyword(s):  
Age Structure ◽  
Statistical Data ◽  
Survival Rates ◽  
Age Distribution ◽  
Cumulative Distribution ◽  
High Tech ◽  
Teaching Staff ◽  
Scientific Publications ◽  
Aggregated Data ◽  
Age Category

Introduction. Personnel of the highest scientific qualification are the basis of staffing the competitive development all sectors of the national economy of the Russian Federation. At the same time, there is no reliable statistical information about the total number of Candidates and Doctors of Sciences and their age structure. Scientific publications do not present approaches to carry out the estimate of the number of persons with scientific degrees. Materials and Methods. The article proposes a model for calculating the age-specific number of Candidates and Doctors of Sciences on the basis of annual statistical data on the number of defenses of candidate and doctoral theses and survival rates. Since the detailed data are presented only for the period starting from 2008, and the aggregated data are not known for all years, the corresponding interpolation methods are proposed to restore the missing data. According to the proposed models, calculations of estimates of the number of Candidates and Doctors of Sciences are made, approximation functions are constructed. The results of the calculations were verified on the basis of statistical data on the number of researchers with a degree of Candidate and Doctor of Sciences in different sectors of the economy and the number of Candidates and Doctors of Sciences among the teaching staff of universities. Results. The results of the study are 6 models for calculating the number of Candidates and Doctors of Sciences, approximation function of the multiplicative survival coefficient for persons with scientific degrees, approximation functions of the age distribution of the applicants of degrees of Candidate and Doctor of Science, approximation functions of agerelated and cumulative distribution of the number of Candidates and Doctors of Sciences, quantitative estimates of the number of Candidates and Doctors of Sciences in 2019. Discussion and Conclusion. The proposed models have shown their adequacy. As a result of the calculations, it was found that the number of Candidates of Sciences in the age category of 20–80 years is 468,000 people, and the number of Doctors of Sciences in the age category of 30–90 years is 72,000 people. According to the obtained numerical values, approximating functions were constructed to get the number of Candidates and Doctors of Sciences in any age range. Since the system of personnel of the highest scientific qualification is sufficiently inert, the data obtained of age structure of the personnel of the highest scientific qualification will retain its character for at least another 10 years. The obtained estimates of the number of persons with scientific degrees allow us to characterize the personnel potential for decision-making in the management of high-tech sectors of the economy. The constructed models can be used to solve the problems of forecasting in the field of development of science-intensive technologies and in higher education for the training of highly qualified scientific personnel and replenishment of the scientific community.

scholarly journals Population dynamics of the endangered mountain ecotype of woodland caribou (Rangifer tarandus caribou) in British Columbia, Canada

2020 ◽  
Author(s):  
Heiko Wittmer ◽  
BN McLellan ◽  
DR Seip ◽  
JA Young ◽  
TA Kinley ◽  
...  
Keyword(s):  
British Columbia ◽  
Population Dynamics ◽  
Rangifer Tarandus ◽  
Population Decline ◽  
Survival Rates ◽  
Adult Survival ◽  
Rangifer Tarandus Caribou ◽  
Vital Rates ◽  
Woodland Caribou ◽  
Annual Survival

We used census results and radiotelemetry locations of >380 collared individuals sampled over the entire distribution of the endangered mountain ecotype of woodland caribou (Rangifer tarandus caribou (Gmelin, 1788)) in British Columbia, Canada, to delineate population structure and document the size and trend of the identified populations. We also describe the spatial pattern of decline and the causes and timing of adult mortality and provide estimates of vital rates necessary to develop a population viability analysis. Our results indicate that the abundance of mountain caribou in British Columbia is declining. We found adult female annual survival rates below annual survival rates commonly reported for large ungulates. The major proximate cause of population decline appears to be predation on adult caribou. Spatial patterns of population dynamics revealed a continuous range contraction and an increasing fragmentation of mountain caribou into smaller, isolated subpopulations. The population fragmentation process predominantly occurs at the outer boundaries of the current distribution. Our results indicate that recovery strategies for mountain caribou should be directed at factors contributing to the fragmentation and isolation of mountain caribou populations as well as management strategies aimed at increasing adult survival. © 2005 NRC Canada.

Pediatric Cancer Registry in Turkey 2009-2018 (TPOG & TPHD).

2019 ◽  
Vol 37 (15_suppl) ◽  
pp. e21510-e21510
Author(s):  
M. Tezer Kutluk ◽  
Akif Yeşilipek
Keyword(s):  
Childhood Cancer ◽  
Children And Adolescents ◽  
Cancer Registry ◽  
Pediatric Cancer ◽  
Health Care Professionals ◽  
Survival Rates ◽  
Age Distribution ◽  
Soft Tissue Sarcomas ◽  
Cancer Registries ◽  
Term Survival

e21510 Background: In Children and adolescents aged 0-14, each year more than 200.000 new cancer cases are expected at global level. For the planning and implementation of an effective pediatric cancer control program, pediatric cancer registries are essential. The long term survival rates have been improved to 85% in high income countries, however it is still less than this in LMICs. This work presents the most updated results of the pediatric cancer registry in Turkey. Methods: Turkish Pediatric Oncology Group and Turkish Pediatric Hematology Association has established the Pediatric Cancer Registry in 2002. The childhood cancer cases registered between 2009-2018 was included in this analysis. International Childhood Cancer Classification System was used for the classification. Essential demographic findings, ICD-O-3 morphology and topography codes were recorded for each case. Results: During the 10 years from 2009 to 2018, 15713 cases were registered. For all cases, median age was 6.7 year (0-17; M/F 8838/6867, 3 hermaphrodite, 5 unknown). Age distribution was 0-4 yrs, 40.7%; 5-9 yrs, 24.4%; 10-14 yrs, 23.2%; 15-19 yrs, 11.7%) The distribution of the tumor types were [number of cases, percentage of total, median age yrs, M/F]: Leukemia (4368, 27.8%, 5.4, 2519/1849); Lymphoma & other RES tumors (2996, 19.1%, 9.7, 2012/979, 1 hermaphrodite & 4 unknown); CNS [brain & spinal] (2089, 13.3%, 7.1, 1142/947); Symphatetic system (1243, 7.9%, 2.4, 650/593); Retinoblastoma (358, 2.3%, 1.4, 204/154); Renal (788, 5.0%, 3.3, 369/419); Liver (260, 1.7%, 1.8, 143/117); Malignant bone (1030, 6.6%, 12.6, 566/464); Soft tissue sarcomas (1052, 6.7%, 7.4, 611/441); Germ cell (971, 6.2%, 8.4, 346/622, 2 hermaphrodite, 1 unknown); Carcinoma & other malignant epithelial (462, 2.9%, 13.7, 226/236); Other/non-specific malignant (96, 0.5%, 7.8, 50/46). Five year survival rate was found as 70.8%. Conclusions: This registry has been used widely among health care professionals since its establishment in 2002. Survival rates for children and adolescents has been improved to 70%. This level of survival is at the acceptable level for an upper middle income country. This registry became a useful source for investigator and decision makers at national and international level.

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