The reproductive season of Newfoundland caribou

1975 ◽  
Vol 53 (9) ◽  
pp. 1213-1221 ◽  
Author(s):  
A. T. Bergerud
Keyword(s):  
Estrous Cycle ◽  
Rangifer Tarandus ◽  
Reproductive Season ◽  
Winter Diet ◽  
Length Of Gestation

The length of estrus, length of the estrous cycle, dates of breeding and calving, and length of gestation were investigated for Newfoundland caribou (Rangifer tarandus). The length of heat was about 48 h and the length of the estrous cycle was thought to be 10–12 days. Breeding observed during 5 years occurred between October 9 and October 19. In 6 years of observations, 90% of the calves were born in about a 12-day period, usually between May 24 and June 5. Information is provided on the weight of calves at birth. The gestation for four wild females with adequate winter diet was 229 days.

Assessing terrestrial lichen biomass using ecoforest maps: a suitable approach to plan conservation areas for forest-dwelling caribou

2011 ◽  
Vol 41 (3) ◽  
pp. 632-642 ◽  
Author(s):  
Rémi Lesmerises ◽  
Jean-Pierre Ouellet ◽  
Martin-Hugues St-Laurent
Keyword(s):  
Rangifer Tarandus ◽  
Population Level ◽  
Landscape Scale ◽  
Stand Age ◽  
Conservation Areas ◽  
Management Guidelines ◽  
Winter Diet ◽  
Population Maintenance ◽  
Saguenay River ◽  
Terrestrial Lichen

Terrestrial lichens are an important part of the winter diet of forest-dwelling caribou ( Rangifer tarandus caribou (Gmelin, 1788)), and developing forest management guidelines to support high lichen biomass could enhance both individual- and population-level health of this threatened species. Our objective was to develop an index to assess terrestrial lichen biomass available to caribou at the landscape scale using ecoforest maps based on forest characteristics (age, density, and height) and geographical variables (slope, altitude, and latitude). We sampled 439 sites within 8340 km2 of the spruce–moss domain located >100 km north of the Saguenay River (Quebec, Canada). Since they are known to support terrestrial lichen, we sampled only spruce-dominated stands older than 50 years, representing 41.8% of the study area. Using a two-step approach, we first modeled lichen occurrence and thereafter lichen biomass in sites where lichens were found. Lichen occurrence was positively correlated with latitude but negatively with stand age, height, and density. Lichen biomass was primarily a function of altitude and tree density. Using this index could prioritize conservation of areas that are most likely to contain high lichen biomass, thus favoring caribou population maintenance in logged landscapes.

Competition potential between sympatric woodland caribou and wood bison in southwestern Yukon, Canada

2005 ◽  
Vol 83 (9) ◽  
pp. 1162-1173 ◽  
Author(s):  
Lisa A Fischer ◽  
C Cormack Gates
Keyword(s):  
Resource Selection ◽  
Rangifer Tarandus ◽  
Aerial Survey ◽  
Bison Bison ◽  
Late Winter ◽  
Lake Area ◽  
Woodland Caribou ◽  
Winter Diet ◽  
Wood Bison ◽  
Utilization Distributions

Wood bison (Bison bison athabascae Rhoads, 1898) were reintroduced to the Aishihik Lake area in the southwestern Yukon, where a population of woodland caribou (Rangifer tarandus caribou (Gmelin, 1788)) existed. These species co-occurred in nearby Beringia over several hundred thousand years and in the study area throughout most of the Holocene. We hypothesized that resource-selection patterns should differ widely between species at all scales because co-evolution should have resulted in strong patterns of resource partitioning. We compared winter utilization distributions of both species based on aerial survey data and assessed differential resource selection at the scales of landscape and distributional overlap. We also assessed differential resource use within feeding sites and compared late-winter diets of the two species. We found 41% overlap in 95% utilization distributions but only 6% overlap in 50% utilization distributions. Strong differences were measured for use of space and terrain, including elevation, slope, and distance from permanent water bodies. Bison strongly selected for or used graminoids, while caribou selected for or used lichens at each scale. Overlap in winter diet between the two species was 10%. At current densities, exploitative competition in winter between these species is unlikely.

scholarly journals Plasma concentrations of progesterone, oestradiol, LH and 15-ketodihydro-PGF2  in Norwegian semi-domestic reindeer (Rangifer tarandus tarandus) during their first reproductive season

Reproduction ◽  
1995 ◽  
Vol 105 (2) ◽  
pp. 307-314 ◽  
Author(s):  
E. Ropstad ◽  
M. Forsberg ◽  
J. E. Sire ◽  
H. Kindahl ◽  
T. Nilsen ◽  
...  
Keyword(s):  
Rangifer Tarandus ◽  
Plasma Concentrations ◽  
Reproductive Season ◽  
Rangifer Tarandus Tarandus

scholarly journals EFFECTS OF A COMBINATION OF PEPTIDE EXTRACTS FROM REINDEER ENDOCRINE GLANDS (RANGIFER TARANDUS) ON THE CATHOLAMINERGIC REGULATION OF THE ESTRAL FUNCTION IN RATS

Biomeditsina ◽  
2019 ◽  
pp. 46-57
Author(s):  
D. A. Abaimov ◽  
A. N. Osintsev ◽  
A. V. Sharabanov ◽  
M. S. Dulya ◽  
R. A. Ageldinov ◽  
...  
Keyword(s):  
Estrous Cycle ◽  
Rangifer Tarandus ◽  
Phase Changes ◽  
Female Rats ◽  
Endocrine Glands ◽  
Urinary Catecholamines ◽  
Delayed Effects ◽  
Age Related ◽  
Age Dependent ◽  
Cycle Disorders

This study was aimed at investigating the concentration of urinary catecholamines in female rats both in the normal state and during the development of age-dependent changes associated with estrous cycle disorders at early menopause stages. In addition, we set out to assess possible corrective and delayed effects of a combination of peptide extracts from reindeer endocrine glands (Rangifer tarandus) on both phase changes in the estrous cycle and age-related disorders in the functioning of the hypothalamus — adenohypophysis — gonadal system in experimental animals.

scholarly journals Reindeer (Rangifer tarandus) and climate change: Importance of winter forage

Rangifer ◽  
2002 ◽  
Vol 22 (1) ◽  
pp. 13 ◽  
Author(s):  
Thrine Moen Heggberget ◽  
Eldar Gaare ◽  
John P. Ball
Keyword(s):  
Climate Change ◽  
Global Warming ◽  
Vascular Plants ◽  
Rangifer Tarandus ◽  
Time Perspective ◽  
Plant Biomass ◽  
Population Decline ◽  
Regeneration Rate ◽  
Winter Diet ◽  
Snow Condition

As a consequence of increasing greenhouse gas concentrations, climate change is predicted to be particularly pronounced, although regionally variable, in the vast arctic, sub-arctic and alpine tundra areas of the northern hemisphere. Here, we review winter foraging conditions for reindeer and caribou (Rangifer tarandus) living in these areas, and consider diet, forage quality and distribution, accessibility due to snow variation, and effects of snow condition on reindeer and caribou populations. Finally, we hypothesise how global warming may affect wild mountain reindeer herds in South Norway. Energy-rich lichens often dominate reindeer and caribou diets. The animals also prefer lichens, and their productivity has been shown to be higher on lichen-rich than on lichen-poor ranges. Nevertheless, this energy source appears to be neither sufficient as winter diet for reindeer or caribou (at least for pregnant females) nor necessary. Some reindeer and caribou populations seem to be better adapted to a non-lichen winter diet, e.g. by a larger alimentary tract. Shrubs appear to be the most common alternative winter forage, while some grasses appear to represent a good, nutritionally-balanced winter diet. Reindeer/caribou make good use of a wide variety of plants in winter, including dead and dry parts that are digested more than expected based on their fibre content. The diversity of winter forage is probably important for the mineral content of the diet. A lichen-dominated winter diet may be deficient in essential dietary elements, e.g. minerals. Sodium in particular may be marginal in inland winter ranges. Our review indicates that most Rangifer populations with lichen-dominated winter diets are either periodically or continuously heavily harvested by humans or predators. However, when population size is mainly limited by food, accessible lichen resources are often depleted. Plant studies simulating climatic change indicate that a warmer, wetter climate may cause an altitudinal upward shift in the production of mat-forming lichens in alpine, sub-arctic regions. This is due to an increased potential for lichen growth at high altitudes, combined with increased competition from taller-growing vascular plants at lower altitudes, where the biomass of Betula nana in particular will increase. Matforming lichens dominant on dry, windblown ridges are easily overgrazed at high reindeer densities. This has longterm effects due to lichens’ slow regeneration rate, but may also reduce competition from vascular plants in a long time perspective. Fires may act in a similar way in some forested areas. Accessibility of winter forage depends on plant biomass, snow depth and hardness; ice crusts or exceptionally deep snow may result in starvation and increased animal mortality. Calf recruitment appears to be low and/or highly variable where winter ranges are overgrazed and hard or deep snow is common. Population decline in several Rangifer tarandus spp. has been associated with snow-rich winters. Effects tend to be delayed and cumulative, particularly on calves. This is mainly ascribed to feeding conditions for young animals which later affect age at maturation. Global warming may increase the frequency of deep or hard snow on reindeer ranges in Norway, due to increased precipitation and more frequent mild periods in winter. We hypothesise that potential benefits from increased plant productivity due to global warming will be counteracted by shifts in the distribution of preferred lichen forage, reduction of the areas of suitable winter ranges, and generally reduced forage accessibility in winter.

scholarly journals A NON-INVASIVE TECHNIQUE USING TO MONITOR REPRODUCTIVE HORMONES IN COMMON PALM CIVETS

2018 ◽  
Vol 40 (3) ◽  
Author(s):  
Nguyen Thi Thu Hien ◽  
Nguyen Thi Phuong Thao ◽  
Nguyen Thanh Binh
Keyword(s):  
Estrous Cycle ◽  
Adult Female ◽  
Reproductive Hormones ◽  
Reproductive Season ◽  
Invasive Technique ◽  
Elisa Kit ◽  
Non Invasive ◽  
Fecal Steroid ◽  
Progesterone Metabolites ◽  
Fully Automatic

Fecal steroid assays have been used to study and provide information on the estrous cycle, pregnancy, re-estrus, reproductive season and therapeutic treatments in an expanded list of species. The purpose of the present study was to monitor the reproductive status of the Commom Palm Civets (Paradoxurus hermaphroditus) by fecal steroid assays. The study was conducted to collect 2635 fecal samples from 12 adult female civets in Dong Nai Biotechnology Center. The fecal contents of Progesterone (P4) and Estradiol (E2) were determinned by using fully automatic ELISA Dynex DS2 (Dynex, USA), Progesterone and Estradiol ELISA Kit (DRG International, Inc., Germany). In non-pregnancy civets, the concentrations of fecal E2 ranged from 0.05 to 7.01 μg/g df, with an average of 1.07 ± 0.84 μg/g and a peak of 3.22 ± 0.64 μg/g. Fecal progesterone metabolites were from 0.15 to 12.32 μg/g, the overall mean of the samples was 1.72 ± 2.16 μg/g. The period of change in E2 content averaging was 28.6 ± 2.29 days. During pregnancy, the P4 content in the stool ranged from 6.21-23.12 μg/g, an average of 15.17 ± 5.22 μg/g and approximately 5 to 7 fold higher than non-pregnant (P

scholarly journals Early fall and late winter diets of migratory caribou in northwest Alaska

Rangifer ◽  
2018 ◽  
Vol 38 (1) ◽  
pp. 27-38 ◽  
Author(s):  
Kyle Joly ◽  
Matthew D. Cameron
Keyword(s):  
Rangifer Tarandus ◽  
Physiological Stress ◽  
Late Summer ◽  
Late Winter ◽  
Winter Habitat ◽  
Pregnant Females ◽  
Winter Diet ◽  
Early Fall ◽  
Forage Type ◽  
Winter Diets

Lichens are the primary winter forage for large herds of migratory caribou (Rangifer tarandus). Caribou select for lichens more than they are available across the landscape and they generally avoid, during winter, habitat that has been burned by wildfires for decades while lichen abundance recovers. However, the relative importance of lichens in the diet is subject to debate. From 2010-2013, we conducted one of the largest microhistological studies of the early fall (58 samples from 1 site) and late winter (338 samples from 58 sites) diets of barren-ground caribou. Lichens con­stituted ~ 71% of the late winter diets of caribou in northwest Alaska, whereas moss (11%) and shrubs (9%) were the next most common forage items. Early fall diets were very similar to late winter, perhaps because deciduous vegetation is senescent during both periods. Diets of males, non-pregnant females and pregnant females were not significantly different. Pregnancy was not associated with the abundance of any forage type during winter but was associated with higher physiological stress. This result was expected as fall body condition dictates conception, caribou are ‘capital’ breeders, and gestation can be energetically demanding. Caribou that migrated south (i.e., wintered south of 67.1°N) had lower levels of nutritional stress, higher levels of lichen in the diet, and lower levels of moss and shrubs compared to caribou that did not migrate south. Future investigations into the potential connection between lichen abundance in the winter diet and survivorship, as well as linking the late summer diets of individuals to their reproductive success, should be undertaken.

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