Seasonal variations in total and alimentary nutrient concentrations and pools in European roe deer (Capreolus capreolus)

Holand, Øystein

doi:10.1016/0300-9629(94)90041-8

Cited by 5 publications

(2 citation statements)

References 24 publications

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“…We realize that use of FN does not necessarily reflect value, but the number of published applications during the past 22 years indicates that peer reviewers of literature from a notable variety of scientific disciplines view FN as an acceptable proxy for nutritional status, which can be used to contrast study units when carefully defined by the study 1986, Beier 1987, Robbins et al 1987, Howery and Pfister 1990, Ruthven et al 1994, Brown et al 1995, Jenks et al 1996, Osborn and Jenks 1998, Sams et al 1998, Osborn and Ginnett 2001, Osborn et al 2002 a Sixteen publications cited the 3 JWM publications but did not report any new FN data: Molvar et al 1993, Pietersen et al 1993, Holand 1994, Wehausen 1995, Garrott et al 1996, Grant et al 1996a, Jiang and Hudson 1996, Main and Coblentz 1996, Meissner and Pieterse 1996, Kohn and Wayne 1997, Cook et al 2001, Dennehy 2001, Spaeth et al 2002, Clark et al 2003, Mooring et al 2003, Li et al 2004 design. Nevertheless, any index can have shortcomings, and we caution that there are still circumstances when application of FN is problematic and must be done so to minimize shortcomings.…”

Section: Discussionmentioning

confidence: 99%

Facts From Feces: Nitrogen Still Measures Up as a Nutritional Index for Mammalian Herbivores

2008

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Fecal nitrogen (FN) has been applied widely as an index of dietary quality in studies of nutritional ecology of free‐ranging and captive vertebrate herbivores, particularly ruminants. Three related articles in the Journal of Wildlife Management (JWM; Leslie and Starkey 1985, 1987; Hobbs 1987) have been cited (n = 150) in 87 publications and 39 peer‐reviewed journals. The critique by Hobbs (1987) and the reply by Leslie and Starkey (1987) on limitations and appropriate applications of FN have been used to justify use of FN or negate its value as a nutritional proxy. We undertook a retrospective analysis of FN applications since 1985, largely because we sensed that methodological cautions noted in the 3 JWM publications were not being followed, leading to faulty conclusions and management applications, and that application protocols needed updating. From January 1986 through July 2007, the 107 species‐by‐continent applications of FN, citing the 3 JWM publications singly or in any combination, were diverse; FN was used in various ways on 5 continents and for 50 wild and domestic species. Cumulative rates of departure from recommended FN applications increased in recent years, largely in studies that compare different species while failing to fully acknowledge that differences likely reflected digestive capabilities rather than differences in some aspect of dietary intake. Post‐1985 research on plant secondary compounds (e.g., tannins) has refined limitations to the application of FN, permitting more straightforward protocols than were possible in 1985. Although use does not necessarily reflect value, the number of published applications during the past 22 years indicates that peer reviewers from a variety of scientific disciplines view FN as a suitable proxy for nutritional status, which can be used to contrast study units when carefully defined by the study design. Any index can have shortcomings, and there are still circumstances when application of FN is problematic. Precise prediction of intake with FN under field conditions is still hampered by inherent variability, but contrasts of comparable study units and species can be appropriate. Published protocols for FN, as amended herein, should be adhered to, and conclusions are strengthened by the use of multiple nutritional indices.

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Section: Discussionmentioning

confidence: 99%

Facts From Feces: Nitrogen Still Measures Up as a Nutritional Index for Mammalian Herbivores

2008

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“…The difference in the digestibility of carnivore and herbivore diets leads to a generally higher digesta load in herbivores (Davis, Davis, & Powers, ), especially beyond the small intestine; water therefore must be extracted from a greater amount of digesta, thus requiring a longer large intestine. Many studies have demonstrated that the dry matter content of digesta in the ruminant hindgut increases steadily along the large intestine, reaching its peak in the faeces (Clauss et al, , ; Clemens & Maloiy, ; Holand, ; Skadhauge, Clemens, & Maloiy, ; Staaland, Pehrson, Jordan, & Palo, ; Staaland & Thing, ; Staaland & White, ; Woodall & Skinner, ). The correlations of the present study, with longer large intestines in animals that produce drier faeces or live in habitats with higher potential evapotranspiration, support the concept that the length of the large intestine is, to a large extent, an adaptation to aridity and requirement for water reabsorption of ruminant species—a requirement that is not directly related to feeding type (Clauss et al, ).…”

Section: Discussionmentioning

confidence: 99%

Gross intestinal morphometry and allometry in ruminants

McGrosky

Codron

Müller

et al. 2019

Journal of Morphology

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While some descriptions of ruminants' dietary adaptations suggest that the length of the intestinal tract reflects the proportion of grass or browse in the diet, this assumption has been questioned. We collated data on body mass (BM), as well as small intestine, caecum, colon/rectum, large and total intestine length in 68 ruminant species, and, while accounting for the phylogenetic structure of the dataset, evaluated both allometric scaling and the potential influence of diet, digestive physiology or climate proxies on measures of intestine length. Intestinal length generally scaled to BM at an exponent higher than the 0.33 expected due to geometry. Diet or digestive physiology proxies did not have an influence on any intestinal length measures, though some proxies indicating more arid natural habitats were positively correlated with measures of the large intestine. The relative size of a forestomach compartment, the omasum, was negatively correlated with intestine length. The results indicate that intestine length measures provide little indication of feeding type or digestive physiology, but rather indicate adaptations to aridity. Higher-than-geometry scaling of intestinal length may be related to the necessity of maintaining geometric (or metabolic) scaling of intestinal surface area while keeping gut diameter, and hence the diffusion distances, small. The way in which space trade-offs determine the macroanatomy of different organs in the abdominal cavity, such as the omasum and the intestine, deserves further investigation. K E Y W O R D S digestion, feeding type, fluid throughput, omasum, ruminant

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Anonymous fecal sampling and NIRS studies of diet quality: Problem or opportunity?

Corlatti

2020

Ecology and Evolution

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Investigating the drivers of diet quality is a key issue in wildlife ecology and conservation. Fecal near infrared reflectance spectroscopy (f‐NIRS) is widely used to assess dietary quality since it allows for noninvasive, rapid, and low‐cost analysis of nutrients. Samples for f‐NIRS can be collected and analyzed with or without knowledge of animal identities. While anonymous sampling allows to reduce the costs of individual identification, as it neither requires physical captures nor DNA genotyping, it neglects the potential effects of individual variation. As a consequence, regression models fitted to investigate the drivers of dietary quality may suffer severe issues of pseudoreplication. I investigated the relationship between crude protein and ecological predictors at different time periods to assess the level of individual heterogeneity in diet quality of 22 marked chamois Rupicapra rupicapra monitored over 2 years. Models with and without individual grouping effect were fitted to simulate identifiable and anonymous fecal sampling, and model estimates were compared to evaluate the consequences of anonymizing data collection and analysis. The variance explained by the individual random effect and the value of diet repeatability varied with seasons and peaked in winter. Despite the occurrence of individual variation in dietary quality, ecological parameter estimates under identifiable or anonymous sampling were consistently similar. This study suggests that anonymous fecal sampling may provide robust estimates of the relationship between dietary quality and ecological correlates. However, since the level of individual heterogeneity in dietary quality may vary with species‐ or study‐specific features, inconsequential pseudoreplication should not be assumed in other taxa. When individual differences are known to be inconsequential, anonymous sampling allows to optimize the trade‐off between sampling intensity and representativeness. When pseudoreplication is consequential, however, no conclusive remedy exists to effectively resolve nonindependence.

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Seasonal variations in total and alimentary nutrient concentrations and pools in European roe deer (Capreolus capreolus)

Cited by 5 publications

References 24 publications

Facts From Feces: Nitrogen Still Measures Up as a Nutritional Index for Mammalian Herbivores

Facts From Feces: Nitrogen Still Measures Up as a Nutritional Index for Mammalian Herbivores

Gross intestinal morphometry and allometry in ruminants

Anonymous fecal sampling and NIRS studies of diet quality: Problem or opportunity?

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