Influence of Type and Level of Grain and Diethylstilbestrol on the Rumen Microbial Populations of Steers Fed All-Concentrate Diets

Slyter, L. L.; Oltjen, R. R.; Kern, D. L.; Blank, F.

doi:10.2527/jas1970.315996x

Cited by 62 publications

(29 citation statements)

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“…Eadie and Mann (1970) and Slyter et al (1970) describe how high concentrate diets decreased rumen protozoa numbers considerably, due to the increasingly acidic conditions observed as levels of fermentable carbohydrate increased. Protozoa have been shown to slow ruminal starch fermentation (Mackie and Gilchrist, 1978;Mendoza et al, 1993).…”

Section: Starch Digestion In the Reticulorumenmentioning

confidence: 99%

“…This is a direct result of the low pH tolerance of the amylolytic bacteria and the high level of activity of their enzymic secretions under these conditions. The less acid tolerant protozoa may be depleted in number below a certain threshold pH (Slyter et al, 1970), which may lead to an increased availability of starch to the bacteria and a more rapid fermentation of this starch. Therefore any effect of pH on starch fermentation in the rumen is principally via a change in the structure of the microbial population, and the effect on fibre degradation may be more pronounced than the direct effects on starch degradation.…”

Section: Nutritional Interactionsmentioning

confidence: 99%

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A review of starch digestion in the lactating dairy cow and proposals for a mechanistic model: 1. Dietary starch characterisation and ruminal starch digestion

Mills¹,

France²,

Dijkstra³

1999

J. Anim. Feed Sci.

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The objective of this paper is to review the literature concerning starch digestion in the rumen of the lactating dairy cow and to propose the framework for a mechanistic model representing this process that may be used as part of a larger model of whole rumen function. The review defines starch as it occurs in the diet of the dairy cow, followed by a detailed description of the digestion of starch in the rumen. Emphasis is placed on the role of the microbial population in the degradation of starch and the significance of both amylolytic bacteria and protozoa. During the investigation, use is made of data gathered from both in vivo, in vitro and in situ studies concerning mainly lactating dairy cows. Regression relationships are presented to describe the significance of dietary starch intake, starch source and processing method on digestion characteristics. The quantity of rumen escape starch is increased at high starch intakes. Maize and sorghum starches tend to be more slowly degraded within the rumen than other cereals and they also benefit to a greater extent from physical and chemical processing techniques designed to increase ruminal and total tract starch digestion. Other factors influencing the nature of starch digestion are also presented in order to allow the interpretation of experimental data and hence the development of a conceptual model of starch digestion. The review subsequently examines starch digestion in the rumen as it is represented in extant models of ruminant digestion. The essential elements of a rumen model that would accurately account for the fate of dietary starch within the rumen are identified. Finally, a scheme representing starch digestion in the dairy cow that may be incorporated into a model of whole rumen function is presented.

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Section: Starch Digestion In the Reticulorumenmentioning

confidence: 99%

Section: Nutritional Interactionsmentioning

confidence: 99%

A review of starch digestion in the lactating dairy cow and proposals for a mechanistic model: 1. Dietary starch characterisation and ruminal starch digestion

Mills¹,

France²,

Dijkstra³

1999

J. Anim. Feed Sci.

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“…Of interest was the fractional passage rate of protozoa from the rumen. Not all studies support the premise that defaunation on high-concentrate diets is solely the result of low rumen pH (Slyter et al 1970;Lyle et al 1981;Towne et al 1990). Instead, we propose that reduced protozoal numbers in the rumen with high-concentrate diets could also be partially the result of decreased bulk in the rumen and therefore decreased material on which protozoa can be selectively retained.…”

Section: Protozoa Fractional Passage Ratementioning

confidence: 60%

Improving the prediction of methane production and representation of rumen fermentation for finishing beef cattle within a mechanistic model

Ellis¹,

Dijkstra²,

Bannink³

et al. 2014

Can. J. Anim. Sci.

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“…It may be that these significant changes in rumen pH were largely responsible for the present study's greater extremes in VFA pattern. A further component that has often been associated with a low pH is a high VFA concentration (OLTJEN et al 1967;SLYTER et al 1970). However such nilationships arc not universally observed as substantiated by the present study although the mean total VFA concentration of the propionate group was about 10 % higher than that of the butyrate group.…”

Section: Discussionmentioning

confidence: 98%

Interrelationships in the Digestion of Sheep Given Barley Grain Diets Containing Either Fish Meal, Soya-bean Meal or Urea

Ling

Swan

Buttery

1983

Archiv für Tierernaehrung

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Three sheep, each fitted with a ruminal cannula and duodenal re-entrant cannulae were given three isonitrogenous, isoenergetic diets in a Latin Square design. Each diet contained approximately 60% DM as barley grain and 40% of total N as either white fish meal, soya-bean meal or urea. These diets were fed continuously and supplied about 28 g N/day. Diets containing such large amounts of barley grain usually produce wide variations in the rumen volatile fatty acid (VFA) proportions and these have been correlated with various other digestive characteristics. Several ruminal and duodenal components were measured in this study and interrelationships between them sought. The molar proportions of VFA varied widely from 45-67% for acetate, 13-48% for propionate and 7-23% for butyrate. Rumen pH was positively correlated with acetate (P less than 0.01), but negatively so with propionate (P less than 0.01) and butyrate (P less than 0.1). The numbers of rumen ciliate protozoa also varied widely and were related to rumen pH (P less than 0.05) and VFA proportions; positively to acetate (P less than 0.001) and butyrate (P less than 0.01) but negatively to propionate (P less than 0.001). Duodenal N was always less than fed N. The mean composition of this duodenal N was 10.1% ammonia-N, 6.7% RNA-N, 79.0% amino acid-N and 7.3% was unaccounted for. Efficiencies of synthesis of microbial and bacterial crude protein (derived from 35S and 2,6-diaminopimelic acid data) ranged from 10.5 to 42.2 g microbial N per kg apparently digested organic matter (ADOM) and 5.0 to 27.9 g bacterial N per kg ADOM. Division of VFA patterns into either propionate or butyrate type fermentations suggested several further interrelationships. No relationship was established between these fermentation patterns and the extent or efficiency of microbial crude protein synthesis. Possible interrelationships between different digestive characteristics are discussed and a plea made for both more extensive and intensive experimentation before such designation of cause and effect can be assigned.

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Influence of Type and Level of Grain and Diethylstilbestrol on the Rumen Microbial Populations of Steers Fed All-Concentrate Diets

Cited by 62 publications

References 0 publications

A review of starch digestion in the lactating dairy cow and proposals for a mechanistic model: 1. Dietary starch characterisation and ruminal starch digestion

A review of starch digestion in the lactating dairy cow and proposals for a mechanistic model: 1. Dietary starch characterisation and ruminal starch digestion

Improving the prediction of methane production and representation of rumen fermentation for finishing beef cattle within a mechanistic model

Interrelationships in the Digestion of Sheep Given Barley Grain Diets Containing Either Fish Meal, Soya-bean Meal or Urea

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