scholarly journals Biochemical indicators of condition, nutrition and nitrogen excretion in caribou

Rangifer ◽  
1996 ◽  
Vol 16 (4) ◽  
pp. 201 ◽  
Author(s):  
Ray Case
Keyword(s):  
Body Composition ◽  
Adult Female ◽  
Rangifer Tarandus ◽  
Nitrogen Excretion ◽  
Late Winter ◽  
Marrow Fat ◽  
Urea Nitrogen ◽  
Biochemical Indicators ◽  
Fat Reserves ◽  
Nitrogen Concentrations

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<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.

The relationship between fertility and fat reserves of Peary caribou

1982 ◽  
Vol 60 (4) ◽  
pp. 597-602 ◽  
Author(s):  
Donald C. Thomas
Keyword(s):  
Rangifer Tarandus ◽  
Close Association ◽  
Negative Energy ◽  
Pregnancy Rates ◽  
Marrow Fat ◽  
Fat Reserves ◽  
Kidney Fat ◽  
Kidney Fat Index ◽  
Harsh Climate ◽  
Energy Balances

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.

Widespread declines in woodland caribou (Rangifer tarandus caribou) continue in Alberta

2013 ◽  
Vol 91 (12) ◽  
pp. 872-882 ◽  
Author(s):  
D. Hervieux ◽  
M. Hebblewhite ◽  
N.J. DeCesare ◽  
M. Russell ◽  
K. Smith ◽  
...  
Keyword(s):  
Growth Rate ◽  
Adult Female ◽  
Industrial Development ◽  
Rangifer Tarandus ◽  
Population Trend ◽  
Late Winter ◽  
Rangifer Tarandus Caribou ◽  
Woodland Caribou ◽  
Structured Population Model ◽  
Female Survival

Nowhere across Canada is the continued persistence of woodland caribou (Rangifer tarandus caribou (Gmelin, 1788)) more uncertain than in Alberta due to widespread industrial development. A recent Government of Canada critical habitat review determined that habitat conditions within all Alberta boreal ecotype caribou ranges are unlikely or very unlikely to allow for self-sustaining caribou populations. This habitat-based assessment was based only indirectly on empirical population trends. Here, we estimated empirical population trend and growth rate (λ) for 13 of Alberta’s 16 remaining woodland caribou populations (plus one adjacent population from Saskatchewan) from 1994 to 2012 using demographic monitoring of adult female survival and calf recruitment. We captured and radio-collared a total of 1337 adult female caribou in 14 populations and estimated the mean annual adult female survival across all populations as 0.851. We conducted 158 late-winter calf recruitment surveys across the 14 populations classifying 20 872 caribou and estimated mean recruitment of 0.154 calves/cow (i.e., 0.077 female calves/cow). We then combined annual estimates of adult female survival and female calf recruitment within each population in a simple age-structured population model to estimate population trend. Annual population growth rate across caribou populations averaged 0.918, and was significantly declining, λ < 1.0, for 10 of the 14 caribou populations. Our results confirm that woodland caribou are declining rapidly (with a realized decline of approximately 50% every 8 years) across Alberta, and support conclusions from previous habitat-based assessments that the population viability of caribou is currently compromised, supporting development and implementation of recovery actions to reverse trends.

Factors affecting the urinary excretion of urea nitrogen in cattle. III.* High plasma urea nitrogen concentrations

1972 ◽  
Vol 23 (4) ◽  
pp. 727 ◽  
Author(s):  
RF Thornton ◽  
BW Wilson
Keyword(s):  
Nitrogen Concentration ◽  
High Plasma ◽  
Nitrogen Excretion ◽  
Urea Nitrogen ◽  
Plasma Urea ◽  
Factors Affecting ◽  
Linear Relationships ◽  
Nitrogen Concentrations ◽  
51Cr Edta ◽  
Filtered Load

The relationship between urinary urea nitrogen excretion, the filtered load of urea nitrogen, and the plasma urea nitrogen concentration were studied in cows intravenously infused with 0.5–10 g urea nitrogen per hour. These levels of infusion resulted in ranges of plasma urea nitrogen concentration of 12–63 mg/100 ml, of filtered urea nitrogen of 3–19 g/hr, and of urinary urea nitrogen excretion of 2.5–12.7 g/hr. There were linear relationships between the filtered load of urea nitrogen and the plasma urea nitrogen concentration (r = 0.91), between urinary urea nitrogen excretion and the filtered load of urea nitrogen (r = 0.92), and between urinary urea nitrogen excretion and the plasma urea nitrogen concentration (r = 0.97). It was concluded that the amount of urea excreted in the urine was regulated more by the plasma urea concentration than by renal processes such as glomerular filtration rate (GFR), the concentrating ability of the kidneys, or urine flow rate. The capacity of the bovine kidneys to excrete urea and mechanisms involved in the renal excretion of urea are discussed. The successful use of 51Cr-EDTA for the estimation of GFR in cattle is reported in an appendix. __________________ *Part II, Aust. J. Agric. Res., 21: 145 (1970).

scholarly journals Estimating the daily dry matter intake of Svalbard reindeer in late winter

Rangifer ◽  
1987 ◽  
Vol 7 (1) ◽  
pp. 29 ◽  
Author(s):  
Nicholas Tyler
Keyword(s):  
Dry Matter ◽  
Rangifer Tarandus ◽  
Subcutaneous Fat ◽  
High Arctic ◽  
Energy Requirements ◽  
Late Winter ◽  
Substantial Part ◽  
Svalbard Reindeer ◽  
Fat Reserves ◽  
Alternative Suggestion

Svalbard reindeer (Rangifer tarandus platyrhynchus) store large reserves of subcutaneous fat during summer and autumn which, it has been suggested, might be sufficient to meet a substantial part of their energy requirements during winter. An alternative suggestion, however, is that fat is not their main source of energy after all and, moreover, that the principal role of their fat reserves is for enhancing reproductive success rather than for substituting for forage (Tyler, in press). Is it realistic to suggest that these high arctic herbivores could meet the greater part of their energy requirements in winter by feeding, given that the aerial biomass of available forage in Svalbard in late winter is very low? This question was investigated by using a simple model to predict what rate of food intake Svalbard reindeer would have to achieve to maintain energy balance in late winter. The results were surprisingly low: pregnant and nonpregnant females could mett their daily energy demands by consuming 3.1 and 1.7 g dry matter per grazing minute, respectively. This supports the suggestion that Svalbard reindeer could live principally off forage in winter.

Evaluation of several indices for assessment of coyote (Canis latrans) body composition

1995 ◽  
Vol 73 (9) ◽  
pp. 1620-1624 ◽  
Author(s):  
Jean Huot ◽  
Marie-Lazarine Poulle ◽  
Michel Crête
Keyword(s):  
Body Composition ◽  
Canis Latrans ◽  
The Body ◽  
Marrow Fat ◽  
Body Protein ◽  
Fat Reserves ◽  
Kidney Fat ◽  
Kidney Fat Index ◽  
Total Body

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.

Comparative body composition strategies of breeding and nonbreeding female caribou

1999 ◽  
Vol 77 (12) ◽  
pp. 1901-1907 ◽  
Author(s):  
Ann C. Allaye Chan-McLeod ◽  
Robert G White ◽  
Don E Russell
Keyword(s):  
Body Composition ◽  
Body Fat ◽  
Rangifer Tarandus ◽  
Early Spring ◽  
Fat Deposition ◽  
Late Winter ◽  
Body Protein ◽  
Protein Deposition ◽  
Protein Mass ◽  
Free Ranging

We evaluated the effects of season and reproductive status on body fat and body protein masses of free-ranging female barren-ground caribou (Rangifer tarandus granti). Body fat mass fluctuated markedly during the year (by a factor of at least 2) in both reproductive classes, but whereas maximum fatness occurred in autumn (September-November) in nonbreeding females, it did not occur until late winter (March-April) in breeding females. Seasonal changes in dry body protein mass were relatively modest, with annual maxima averaging only 31-43% higher than annual minima. Moreover, seasonal differences between the reproductive classes were not significant except in November-December. Absolute fat deposition by both breeding and nonbreeding females was highest in summer, though fat deposition increased relative to protein deposition in autumn. Between June and September, the primary deposition of body protein in breeding females contrasted with the primary deposition of body fat in nonbreeding females. As a result, breeding females were highly compromised in their fat deposition but not in their protein deposition, which approximated levels in nonlactating females. Differences in body composition between breeding and nonbreeding females were highest in autumn and lowest in early spring because of divergence in summer and convergence in winter.

Body composition of the George River caribou (Rangifer tarandus caribou) in fall and late winter

1989 ◽  
Vol 67 (1) ◽  
pp. 103-107 ◽  
Author(s):  
J. Huot
Keyword(s):  
Body Composition ◽  
Body Fat ◽  
Gravid Uterus ◽  
Late Winter ◽  
Pregnant Females ◽  
Fat Reserves ◽  
Body Weights ◽  
Lactating Females ◽  
Free Body ◽  
George River

The fall and late winter body composition of George River caribou was determined based on a sample of 14 calves, 9 yearlings, and 41 adult females. In fall, the fattest individuals were the adult nonlactating females with 10.62 ± 2.65% ingesta-free body fat. Ingesta-free body fat was 5.25 ± 2.47% for lactating females, 7.76 ± 0.11% for yearlings, and 3.44 ± 0.57% for calves. There was no evidence of depletion of fat reserves between fall (October–December) and mid-April in any age-class, and no change in body weights of calves. However, the ingesta-free body weights of pregnant females in April were 19.8 and 9.5% less than those of nonlactating and lactating females in fall, respectively. These differences were due mainly to a loss of water (9.8 and 7.3 kg) and protein (4.6 and 2.6 kg). This protein loss of the ingesta-free body was not compensated for by growth of the gravid uterus, which accounted for 3.5% (0.53 kg) of the total protein mass of pregnant females in mid-April. These results suggest that, between fall and late winter, the George River caribou were affected more by a deficiency in protein than a negative energy budget and that increased attention should be given to monitor protein reserves. However, in summer and early fall, these caribou accumulated only limited fat reserves as compared with other northern ungulates and the possibility of an energy deficiency during summer should be investigated.

Urea excretion in ruminants. III. The role of the hind-gut (caecum and colon)

1970 ◽  
Vol 21 (2) ◽  
pp. 345 ◽  
Author(s):  
RF Thornton ◽  
PR Bird ◽  
M Somers ◽  
RJ Moir
Keyword(s):  
Terminal Ileum ◽  
Nitrogen Excretion ◽  
Urea Nitrogen ◽  
Plasma Urea ◽  
Urea Excretion ◽  
Dry Matter Digestibility ◽  
Nitrogen Concentrations ◽  
Faecal Nitrogen ◽  
Hind Gut

The transfer of endogenous nitrogen to the hind-gut digesta of sheep and its relationship with urinary nitrogen excretion were studied concurrently with the estimation of nitrogen balance and of dry matter digestibility in sheep fitted with a re-entrant ileal cannula. Infusion of glucose into the terminal ileum increased the excretion of faecal nitrogen by 1 g/day, while the urinary urea nitrogen excretion decreased by 1 g/day, relative to the respective control levels. Plasma urea nitrogen concentrations remained unchanged. When glucose was infused, the excretion of nitrogen in the faeces was higher than the amount of nitrogen passing the terminal ileum. It is suggested that endogenous urea nitrogen was transferred to the digesta of the hind-gut, where it was incorporated into microbial protein and subsequently excreted in the faeces. The transfer of urea from the blood to either of the fermentative areas of the gut tract is apparently the preferential pathway of urea excretion in ruminants.

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