A dynamic model of ruminant digestion for evaluation of factors affecting nutritive value

Baldwin, R.L.; Koong, L. J.; Ulyatt, M. J.

doi:10.1016/0308-521x(77)90020-8

Cited by 104 publications

(49 citation statements)

References 36 publications

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“…More detailed mechanistic models of the rumen have been published for several decades after the pioneering work of Baldwin et al (1977). They have been all based on a bottom up process using rather few data values measured at a fairly underlying level of the rumen system, sometimes in vivo but also frequently in vitro.…”

Section: Resultsmentioning

confidence: 99%

Quantification of the main digestive processes in ruminants: the equations involved in the renewed energy and protein feed evaluation systems

Sauvant

Nozière

2016

Animal

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The evolution of feeding systems for ruminants towards evaluation of diets in terms of multiple responses requires the updating of the calculation of nutrient supply to the animals to make it more accurate on aggregated units (feed unit, or UF, for energy and protein digestible in the intestine, or PDI, for metabolizable protein) and to allow prediction of absorbed nutrients. The present update of the French system is based on the building and interpretation through meta-analysis of large databases on digestion and nutrition of ruminants. Equations involved in the calculation of UF and PDI have been updated, allowing: (1) prediction of the out flow rate of particles and liquid depending on the level of intake and the proportion of concentrate, and the use of this in the calculation of ruminal digestion of protein and starch from in situ data; (2) the system to take into account the effects of the main factors of digestive interactions (level of intake, proportion of concentrate, rumen protein balance) on organic matter digestibility, energy losses in methane and in urine; (3) more accurate calculation of the energy available in the rumen and the efficiency of its use for the microbial protein synthesis. In this renewed model UF and PDI values of feedstuffs vary depending on diet composition, and intake level. Consequently, standard feed table values can be considered as being only indicative. It is thus possible to predict the nutrient supply on a wider range of diets more accurately and in particular to better integrate energy × protein interactions occurring in the gut.

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Section: Resultsmentioning

confidence: 99%

Quantification of the main digestive processes in ruminants: the equations involved in the renewed energy and protein feed evaluation systems

Sauvant

Nozière

2016

Animal

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“…Major areas of work include explanatory models for thermoregulation, blood circulation, morphogenetic control, neurological functioning, and even artificial intelligence. It has even been possible to deal with the biochemical kinetics of ruminant digestion as a basis for organismal growth (5,98). The basis for such work in many instances has been feedback theory developed in the 1940s (6,72,100), enzyme kinetics (42a, 49, 105), and compartmentalization concepts (2,49).…”

Section: Introductionmentioning

confidence: 99%

Explanatory Models in Crop Physiology

Loomis¹,

Rabbinge²,

Ng³

1979

Annu. Rev. Plant. Physiol.

158

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“…Some models do not include a representation of the total amount of VFA formed (France et al, 1982;Russell et al, 1992;Sniffen et al, 1992) or do not distinguish the type of VFA produced (Baldwin et al, 1977 (Sutton, 1985), but the effects of differences in VFA ratios on growth and growth composition vary (McRae and Lobley, 1982 (1992) and Dijkstra (1994). Lescoat and Sauvant (1995) Dijkstra (1994b) analyzed the problems and suggested factors to be included in future attempts to predict VFA profiles.…”

Section: Introductionmentioning

confidence: 99%