Digestion in ruminants

This modification to the ADF method was designed to improve the relationship between the ADF and digestibility in ruminants. The sample drying temperature of 95°C, however, means it is unsuitable for assaying heat damage and unavailable protein (Van Soest, 1982). The method below is based on that given in MAFF/ADAS (1986, pp. 93-94), with Crown Copyright permission. See Chapter 4 for further discussion on fibre extraction procedures. 

Comment When you irradiate wood you increase the digestibility in ruminants quite markedly. You are actually opening up the structure by one means or another. 

Festuca elatior and Lolium multiflorum contain the highest and lowest amounts of perloline (61), an unusual diazaphenanthrene alkaloid which may inhibit digestion in ruminants. It is speculated that Lolium-Festuca hybrids can be developed which show high or low perloline concentrations. 

A phenolic compound that resembles lignans in structure, platyphylloside (61), from Betula pendula, the Scandinavian birch, has been shown to account for 80% of the observed depression of in vitro organic matter digestibility in ruminant test systems (Sunnerheim et al., 1988). This observation cor-... 

Microbial digestion in ruminants and other herbivores The overall equation for the rumen fermentation of hexoses is ... 

Acetic acid is the major product of carbohydrate digestion in ruminants and is the only volatile fatty acid present in the peripheral blood in significant amounts. It is used by a wide variety of tissues as a source of energy. The initial reaction in this case is conversion of acetate to acetyl-coenzyme A in the presence of acetyl-coenzyme A synthetase ... 

Heat of fermentation, as explained earlier (see p. 261), accounts for part of the lower calorimetric efficiency of growth in ruminants thus, it would explain much of the 10 per cent difference in kg between pigs and ruminants fed on similar, mainly concentrate-based diets. However, for a fuller explanation we need to consider the end products of digestion in ruminants. We have already seen in Chapter 8 that much of... 

Actinomyces olivaceus and Propionibacterium shermanii induced by chemical mutagens. PhD thesis. Institute of Genetics of Industrial microorganisms, Moscow Kurilov NV and Sevastjanova NA (1978) Digestion in Ruminants. Itogi Nauki i Tekhniki. 

Uden, P. (1978). Comparative Studies on Rate of Passage, Particle Size and Rate of Digestion in Ruminants, Equines, Rabbits and Man. Ph.D. Thesis. Cornell University, Ithaca, USA. 

Larson J. and P.C. Hoffman, 2008. Technical Note Amethod to quantify prolamin proteins in com that are negatively related to starch digestibility in ruminants. J. Dairy Sci. 91, 4834-4839. 

Masoero, F, L. Fiorentini, F. Rossi and A. Piva, 1994. Determination of nitrogen intestinal digestibility in ruminants. Anim. Feed Sci. Technol. 48, 253-263. 

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