The relationship between fertility and fat reserves of Peary caribou

1982 ◽  
Vol 60 (4) ◽  
pp. 597-602 ◽  
Author(s):  
Donald C. Thomas

There was a close association between pregnancy rates and levels of fat reserves and body weights in Peary caribou (Rangifer tarandus pearyi) collected in the late winters of 1974 through 1977 on several islands in the Canadian Arctic. Pregnancy rates were <8% in adult (>2 years) females weighing <53 kg in March and April, >75% in those weighing >57 kg, and 100% in those >67 kg in weight. Pregnancy rates increased progressively from 7 to 100% as the percentage marrow fat increased from 43 to 79% and the kidney-fat index increased from 24 to 41%. Only heavy (>46 kg) yearling (21 month) females with high fat reserves were pregnant. Reproduction virtually ceased from 1973–1974 to 1975–1976 in Peary caribou on the western Queen Elizabeth Islands because their physical condition was poor. Pregnancy rates were as high as 100% in females in a second population located on Somerset and Prince of Wales islands, and in 1974–1975 four of five yearling females were pregnant. The adjustment of fertility to energy reserves is viewed as an adaptation to conserve energy. It is well developed in Peary caribou whose environment is characterized by a highly variable and often harsh climate in which negative energy balances probably prevail for 8 to 10 months of the year.

Rangifer ◽  
1986 ◽  
Vol 6 (2) ◽  
pp. 219 ◽  
Author(s):  
Mauri Nieminen ◽  
Matti Laitinen

Back-fat depth, kidney-fat index (KFI), fat and triglyceride contents in femur and metatarsal marrows were measured from 92 semi-domesticated reindeer (Rangifer tarandus tarandus L.) in northern Finland during 1980-84. The age of the reindeer varied from 5 months to 10 years and marrow fat content was estimated by five different methods: standard ether extraction, oven-drying (Neiland, 1970), reagent-dry assay (Verme and Holland, 1973), compression method (Greer, 1968) and visual estimation (Cheatum, 1949). The kidney-fat index (Riney, 1955) was significantly related (r=0.892) to the percent marrow fat in femur and metatarsus. The oven-drying method gave high correlations with results obtained by ether extraction and reagent-dry methods. Oven-drying produced a lower mean dry-weight value than reagent-drying (1.31 &plusmn;0.36%). The amount of compression had a concave relationship with the ether-extractable fat content of femur and metatarsal marrows. The subjectiveness of the visual estimation technique limited its use. Femur marrow fat contents (dry-weight %) in reindeer which died from starvation varied between 2 - 8%. Metatarsal fat contents were slightly higher. Adult males had a mean triglyceride content of 46.8 |Jmol/g in August in the femur. Adult females had slightly lower values. The amount of triglycerides was significantly related to the ether-extractable fat content of the femur (r=0.914) and metatarsal (r=0.911).


2004 ◽  
Vol 31 (1) ◽  
pp. 97 ◽  
Author(s):  
Masatsugu Suzuki ◽  
Mayumi Yokoyama ◽  
Manabu Onuma ◽  
Hiroshi Takahashi ◽  
Masami Yamanaka ◽  
...  

We assayed the serum leptin concentration and determined its correlation with the kidney fat mass (KFM), kidney fat index (KFI), and femur marrow fat (FMF) indices in 12 Hokkaido sika deer (Cervus nippon yesoensis Heude, 1884) collected in April, June, and October 2000. The KFM and KFI in April and June were both significantly lower than those in October. The leptin concentrations in April and June and in October were 1.222–1.521 ng mL–1 HE (Human Equivalent) units and 1.676–2.63 ng mL–1 HE, respectively, without overlapping. The relationships between the leptin concentration and the KFM, KFI, and FMF were all significant. Therefore, we conclude that the serum leptin concentration can be used as a new index for fat reserves in Hokkaido sika deer. However, reliable results could not be obtained from four samples collected in April and June when the deer were in a lower nutritional status. This may be due to the limited sensitivity of the antisera in the commercial multi-species leptin RIA kit used. For practical use in wildlife biology, species-specific leptin assays should be developed to eliminate this problem.


1995 ◽  
Vol 73 (9) ◽  
pp. 1620-1624 ◽  
Author(s):  
Jean Huot ◽  
Marie-Lazarine Poulle ◽  
Michel Crête

The body composition of 27 coyotes (Canis latrans) of different ages and both sexes was determined on the basis of chemical analyses of homogenized samples of viscera, carcass, and skin. Regression analyses were used to identify the best indices for estimating fat (lipid reserves), protein, and water body contents. A combined index based on the kidney fat index and the percentage of femur marrow fat was the best indicator of fat reserves. Body mass (whole or skinned carcass) and eviscerated carcass mass were the best predictors of total body protein and total body water contents. A combination of indices is proposed to provide postmortem or in vivo estimates of coyote body composition.


Rangifer ◽  
1996 ◽  
Vol 16 (4) ◽  
pp. 201 ◽  
Author(s):  
Ray Case

Urinary urea nitrogen to creatinine ratios, urinary Nt-methylhistidine to creatinine ratios, serum urea nitrogen concentrations (SUN mg/dl), and serum Nt-methylhistidine concentrations were compared with physical measures of body composition in adult female barren-ground caribou (Rangifer tarandus groenlandicus) from the Bathurst and Southampton Island herds during late winter. Body weight and UUC were used to estimate urinary urea nitrogen (urea-N) excretion in free ranging caribou. Only mean UUC reflected differences in fat reserves between populations. None of the biochemical indicators were directly related to body composition. However, elevated UUC were only observed in caribou with depleted fat reserves as demonstrated by low kidney fat index (KFK40) and/or reduced femur marrow fat (FMF&lt;80). UUC greater than 0.25 were indicative of undernourished animals with depleted fat reserves. SUN and UN -MHC showed no clear relationship with fat reserves. The mean estimated daily urea-N excretion for adult female caribou in late winter was extremely low (0.11+0.01SE g urea-N/day, n=76, range=0.011-0.510). The results of my study suggest that UUC can be used to detect nutritionally stressed caribou with depleted fat reserves on lichen winter ranges.


2021 ◽  
Vol 99 (7) ◽  
pp. 596-613
Author(s):  
Rachel C. Cook ◽  
John A. Crouse ◽  
John G. Cook ◽  
Thomas R. Stephenson

Body composition studies are critical for evaluating the accuracy of nutritional condition indices for predicting body components. We evaluated >40 indices of nutritional condition for caribou (Rangifer tarandus (Linnaeus, 1758)) using 29 female caribou captured from three populations in Alaska (USA) that ranged in condition from 2.3% to 11.2% ingesta-free body fat (IFBF) and 6 captive female caribou that ranged in condition from 8.1% to 26.0% IFBF. Estimates of body fat, protein, and gross energy were regressed against each index of nutritional condition. Generally, indices with linear or slightly curvilinear relations to body fat and those based on multiple fat depots were the most accurate in predicting nutritional condition and the most useful over the full range of nutritional condition. A scaledLIVINDEX (a combination of subcutaneous fat thickness and a condition score), CONINDEX (a combination of kidney fat and marrow fat), and a subset of the Kistner score (pericardium and kidneys only) had the strongest relationship with body fat (r2 > 0.86) and were useful over the entire range of nutritional condition. If used properly and with adequate training, indices of nutritional condition can be a critical tool for understanding the severity and seasonality of nutritional limitations in wild caribou populations.


2019 ◽  
Vol 41 (4) ◽  
pp. 293 ◽  
Author(s):  
Kurt Watter ◽  
Greg Baxter ◽  
Michael Brennan ◽  
Anthony Pople ◽  
Peter Murray

Chital deer (Axis axis) were introduced to the Burdekin district of northern Queensland, Australia in 1886. Compared with most successful ungulate introductions they have been slow to expand their distribution and increase in abundance (Moriarty 2004). In this study we consider the possibility that forage shortages caused by periodic droughts have caused sufficient mortalities to limit the increase and spread of chital in the region. The Burdekin district experiences fluctuations in forage according to seasonal rainfall as well as multi-year droughts. This study recorded the decline in body condition, measured as kidney fat index (KFI) and bone marrow fat (BMF), over the wet and dry seasons of two successive years in two chital deer populations during a period when annual rainfall was ~40% below average. We relate the falls in mean KFI from ~45–15%, and mean BMF from ~80–50% to the surveyed decline in chital populations of ~80%. The extent of the decline implies increased mortalities in all age classes as well as reduced reproductive output. We propose that it is likely that chital populations have experienced several such drought mortality events since the 1890s which have contributed to their limited spread.


1970 ◽  
Vol 18 (4) ◽  
pp. 415 ◽  
Author(s):  
J Bamford

Two hundred possums were collected from an area in Westland, New Zealand. Their carcasses were macerated and total fat content was determined by chemical means. The reliability of existing indices (visual, kidney fat, back fat, marrow fat) for predicting the proportion of total fat in the body was investigated. Two indices were developed and tested; one based on fat depots in the mesogastrium, the other based on deviations from a standardized weight for length. The index based on weight deviations gives good results if derived from a large sample of animals, and has the advantage that it can be used on live animals under sedation. The marrow fat index gives good results if fat reserves are low, and the mesogastric index does at other times, when estimates are obtained by autopsy of a few animals. Analysis of variance showed that, within the population studied, time of the year and a season-age interaction were the only significant sources of heterogeneity in fat reserves.


1984 ◽  
Vol 48 (3) ◽  
pp. 969 ◽  
Author(s):  
Paul E. Johns ◽  
Michael H. Smith ◽  
Ronald K. Chesser

Koedoe ◽  
1973 ◽  
Vol 16 (1) ◽  
Author(s):  
D.A. Els

Changes occuring in marrow fat reserves of animals have been used as an indicator of their physical condition (Cheatum, 1949; Riney, 1955). Cheatum correlated his visual estimate with a chemical analysis and Riney used four different condition classes on red deer  (Cervus elaphus) for both colour and texture.


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