Allometry and ecology of feeding behavior and digestive capacity in herbivores: A review

Soest, P.J. Van

doi:10.1002/(sici)1098-2361(1996)15:5<455::aid-zoo3>3.0.co;2-a

Cited by 189 publications

(165 citation statements)

References 68 publications

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“…The higher OMD CPf measured at pasture has usually been related to the ability of grazing animals to select betterquality forage (Minson, 1990;Van Soest, 1996).…”

Section: Discussionmentioning

confidence: 99%

“…However, the fundamentals of animal feeding at pasture are often based on the extrapolation of results obtained indoors, although some differences may exist between these two ways of feeding. Hence, although a positive correlation between intake and digestibility has been reported indoors (Minson, 1990;Ketelaars and Tolkamp, 1992;Archimede et al, 2000), other studies have reported the opposite at pasture (Hitchcock et al, 1990;Van Soest, 1996;Boval et al, 2007). However, these results were produced in studies carried out with different forage species, under different climatic and management conditions.…”

Section: Introductionmentioning

confidence: 93%

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Comparison of intake and digestibility of fresh Digitaria decumbens grass fed to sheep, indoors or at pasture, at two different stages of regrowth

Fanchone

Archimède

Delagarde

et al. 2012

Animal

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The effect of two feeding systems (indoors and at pasture) on intake and digestion of fresh grass was studied at two stages of regrowth (21 and 35 days of regrowth) in two parallel experiments. In Experiment 1, 10 adult Martinik rams weighing, on average, 50.5 (60.9) kg, including four fitted with rumen cannula, were randomly allocated to two groups according to a 2 3 2 Latin Square design. These rams consumed a 21-day regrowth of Digitaria decumbens grass diet during two successive 28-day periods, indoors (five rams) or at pasture (five tethered rams). In Experiment 2, 10 other Martinik rams weighing, on average, 45.5 (60.9) kg, including four fitted with rumen cannula, were randomly allocated to two groups according to a 2 3 2 Latin Square design. These rams consumed a 35-day regrowth of D. decumbens grass diet during two successive 28-day periods, either indoors (five rams) or at pasture (five tethered rams). For the indoors groups, in vivo organic matter digestibility (OMD) was measured by total collection of feces. In addition, OMD was estimated indoors and at pasture using the fecal CP (CPf ) method (OMD CPf ). Organic matter intake (OMI) was then estimated using OMD CPf and fecal organic matter output (OMI CPf ). Correlations of 0.49 and 0.77 were found between in vivo OMD and OMD CPf (P , 0.05) and between OMI and OMI CPf (P , 0.001), respectively. OMD CPf was 1.8% (P , 0.05) and 2.7% (P , 0.01) lower indoors than at pasture at 21 and 35 days of regrowth, respectively, whereas OMI CPf indoors was 1.1 and 1.16 times that registered at pasture at 21 and 35 days of regrowth, respectively. The higher OMD CPf at pasture was linked to the higher selective behavior of rams at pasture, whereas the differences in OMI CPf between the two feeding systems were linked to differences in the total bulk density of the grass. These studies show that differences in OMD CPf and OMI CPf exist between animals fed indoors and at pasture with the same forage and that these differences may vary according to the stage of regrowth of the grass offered.

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“…The higher OMD CPf measured at pasture has usually been related to the ability of grazing animals to select betterquality forage (Minson, 1990;Van Soest, 1996).…”

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 93%

Comparison of intake and digestibility of fresh Digitaria decumbens grass fed to sheep, indoors or at pasture, at two different stages of regrowth

Fanchone

Archimède

Delagarde

et al. 2012

Animal

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“…Many methods are available but that most widely used is in vitro digestibility (Kitessa et al, 1999) even though values often have to be adjusted to estimate in vivo digestibility. Also, although in Grassland, management and methodological progress tropical pastures some studies (Minson, 1990;Archimede et al, 2000) have reported good relationships, in many others there was often a poor relationship between digestibility and voluntary intake or LW gain (VanSoest, 1996;Boval et al, 2007b).…”

Section: Evaluation Of Pasture Attributesmentioning

confidence: 99%

The importance of grasslands for animal production and other functions: a review on management and methodological progress in the tropics

Boval

Dixon

2012

Animal

186

106

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The global importance of grasslands is indicated by their extent; they comprise some 26% of total land area and 80% of agriculturally productive land. The majority of grasslands are located in tropical developing countries where they are particularly important to the livelihoods of some one billion poor peoples. Grasslands clearly provide the feed base for grazing livestock and thus numerous high-quality foods, but such livestock also provide products such as fertilizer, transport, traction, fibre and leather. In addition, grasslands provide important services and roles including as water catchments, biodiversity reserves, for cultural and recreational needs, and potentially a carbon sink to alleviate greenhouse gas emissions. Inevitably, such functions may conflict with management for production of livestock products. Much of the increasing global demand for meat and milk, particularly from developing countries, will have to be supplied from grassland ecosystems, and this will provide difficult challenges. Increased production of meat and milk generally requires increased intake of metabolizable energy, and thus increased voluntary intake and/or digestibility of diets selected by grazing animals. These will require more widespread and effective application of improved management. Strategies to improve productivity include fertilizer application, grazing management, greater use of crop by-products, legumes and supplements and manipulation of stocking rate and herbage allowance. However, it is often difficult to predict the efficiency and cost-effectiveness of such strategies, particularly in tropical developing country production systems. Evaluation and on-going adjustment of grazing systems require appropriate and reliable assessment criteria, but these are often lacking. A number of emerging technologies may contribute to timely low-cost acquisition of quantitative information to better understand the soil–pasture–animal interactions and animal management in grassland systems. Development of remote imaging of vegetation, global positioning technology, improved diet markers, near IR spectroscopy and modelling provide improved tools for knowledge-based decisions on the productivity constraints of grazing animals. Individual electronic identification of animals offers opportunities for precision management on an individual animal basis for improved productivity. Improved outcomes in the form of livestock products, services and/or other outcomes from grasslands should be possible, but clearly a diversity of solutions are needed for the vast range of environments and social circumstances of global grasslands.

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“…for small (rodent) herbivores (Justice and Smith 1992;Smith 1995), to include effects of differences in relative intake and food sorting; Owen-Smith (1988) and Van Soest (1996) also emphasized that larger ungulates can support their lower specific metabolic requirements either by accepting forage of lower quality, or by ingesting lesser amounts of regular quality forage per day, or some combination of both. Thus, larger animals should eat diets of lower nutritional quality than those selected by smaller herbivores, but the difference should be less marked than predicted simply on the basis of the body size-metabolic rate relationship.…”

Section: Ecophysiological Theories On the Digestive Relevance Of Bodymentioning

confidence: 99%

“…Case 1979;Owen-Smith 1988;Van Wieren 1996;Brashares et al 2000;Gagnon and Chew 2000). This is not due to physiological limitations but to forage abundance (Van Soest 1996). Large species cannot be as selective as small species, and the large amounts of forage necessary to supply large species are available mainly as grasses.…”

Section: Open Questions In Large Herbivore Digestive Physiologymentioning

confidence: 99%

The maximum attainable body size of herbivorous mammals: morphophysiological constraints on foregut, and adaptations of hindgut fermenters

et al. 2003

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The maximum attainable body size of herbivorous mammals: morphophysiological constraints on foregut, and adaptations of hindgut fermenters AbstractAn oft-cited nutritional advantage of large body size is that larger animals have lower relative energy requirements and that, due to their increased gastrointestinal tract (GIT) capacity, they achieve longer ingesta passage rates, which allows them to use forage of lower quality. However, the fermentation of plant material cannot be optimized endlessly; there is a time when plant fibre is totally fermented, and another when energy losses due to methanogenic bacteria become punitive. Therefore, very large herbivores would need to evolve adaptations for a comparative acceleration of ingesta passage. To our knowledge, this phenomenon has not been emphasized in the literature to date. We propose that, among the extant herbivores, elephants, with their comparatively fast passage rate and low digestibility coefficients, are indicators of a trend that allowed even larger hindgut fermenting mammals to exist. The limited existing anatomical data on large hindgut fermenters suggests that both a relative shortening of the GIT, an increase in GIT diameter, and a reduced caecum might contribute to relatively faster ingesta passage; however, more anatomical data is needed to verify these hypotheses. The digestive physiology of large foregut fermenters presents a unique problem: ruminant-and nonruminant-forestomachs were designed to delay ingesta passage, and they limit food intake as a side effect. Therefore, with increasing body size and increasing absolute energy requirements, their relative capacity has to increase in order to compensate for this intake limitation. It seems that the foregut fermenting ungulates did not evolve species in which the intake-limiting effect of the foregut could be reduced, e.g. by special bypass structures, and hence this digestive model imposed an intrinsic body size limit. This limit will be lower the more the natural diet enhances the ingesta retention and hence the intake-limiting effect. Therefore, due to the mechanical characteristics of grass, grazing ruminants cannot become as big as the largest browsing ruminant. Ruminants are not absent from the very large body size classes because their digestive physiology offers no particular advantage, but because their digestive physiology itself intrinsically imposes a body size limit. We suggest that the decreasing ability for colonic water absorption in large grazing ruminants and the largest extant foregut fermenter, the hippopotamus, are an indication of this limit, and are the outcome of the competition of organs for the available space within the abdominal cavity. Our hypotheses are supported by the fossil record on extinct ruminant/tylopod species which did not, with the possible exception of the Sivatheriinae, surpass extant species in maximum body size. In contrast to foregut fermentation, the GIT design of hindgut fermenters allows adaptations for relative passage acceleration, which explai...

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Allometry and ecology of feeding behavior and digestive capacity in herbivores: A review

Cited by 189 publications

References 68 publications

Comparison of intake and digestibility of fresh Digitaria decumbens grass fed to sheep, indoors or at pasture, at two different stages of regrowth

Comparison of intake and digestibility of fresh Digitaria decumbens grass fed to sheep, indoors or at pasture, at two different stages of regrowth

The importance of grasslands for animal production and other functions: a review on management and methodological progress in the tropics

The maximum attainable body size of herbivorous mammals: morphophysiological constraints on foregut, and adaptations of hindgut fermenters

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