Associative effects of mixed feeds. I. effects of type and level of supplementation and the influence of the rumen fluid pH on cellulolysis in vivo and dry matter digestion of various roughages

Mould, F.L.; Ørskov, E. R.; Mann, S. O.

doi:10.1016/0377-8401(83)90003-2

Cited by 452 publications

(210 citation statements)

References 15 publications

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“…However, a negative aspect of such a strategy is the fact that at pH values lower than 6.2, fibre digestion in the rumen is depressed (Mould et al, 1983). This is however of relative importance because lipid supplements are usually fed in combination with low roughage diets.…”

Section: Resultsmentioning

confidence: 99%

Influence of pH on lipolysis and biohydrogenation of soybean oil by rumen contents in vitro

Nevel¹,

Demeyer²

1996

Reprod. Nutr. Dev.

129

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Section: Resultsmentioning

confidence: 99%

Influence of pH on lipolysis and biohydrogenation of soybean oil by rumen contents in vitro

Nevel¹,

Demeyer²

1996

Reprod. Nutr. Dev.

129

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“…The fermentation of high quantities of easily fermentable carbohydrates provided by concentrate feeds results in a decrease of the ruminal pH, which negatively affects cellulolytic activity and subsequently digestibility of plant cell walls (Mould et al, 1983). However, associative effects can also be positive: for instance, protein supplementation of straw may improve its digestibility and voluntary intake, thus alleviating nitrogen deficiency and stimulating the growth of rumen microbes (Church and Santos, 1981;Mawuenyegah et al, 1997).…”

Section: Introductionmentioning

confidence: 99%

Associative effects between forages on feed intake and digestion in ruminants

Niderkorn

Baumont

2009

Animal

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The feeding value of forage mixtures from permanent and temporary multi-species grasslands cannot always be precisely defined. Indeed, the digestibility and feed intake of a combination of forages can differ from the balanced median values calculated from forages considered separately. In order to present an overview of the associative effects between forages on digestion and intake, a literature study was carried out. The associative effects can be studied in a complementary way in vitro to test digestive interactions of a large number of mixtures and to carry out explanatory experiments, and in vivo to investigate intake and digestion at the whole animal scale. We identified three main situations in which interactions between forages can lead to associative effects on intake and digestion: (i) increased intake that can be observed with grass and legume association can be explained by fast digestion of the soluble fraction of legumes, and a higher rate of particle breakdown and passage through the rumen, (ii) increased digestion when a poor forage is supplemented by a high nitrogen content plant can be explained by stimulation of the microbial activity and (iii) modification of digestive processes in the rumen, including proteolysis and methane production when certain bioactive secondary metabolites such as tannins, saponins or polyphenol oxidase are present. According to the type and concentration of these compounds in the diet, the effects can be favourable or unfavourable on intake and digestive parameters. Reported associative effects between forages show a large variability among studies. This reflects the complexity and multiplicity of nutritional situations affecting intake and the rumen function in a given animal. In order to provide more reliable information, further accumulation of data combining in vitro and in vivo studies is required. A better understanding of the associative effects between forages could help to optimise feed use efficiency, resulting in greater productivity, a reduction of the environmental impact of animal emissions and more sustainable animal production.

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“…Thus, in vitro trials Dragomir, Sauvant, Peyraud, Giger-Reverdin and Michalet-Doreau revealed that pH below certain levels would significantly impair or inhibit some rumen functions such as cellulose or microbial proteosynthesis (Shriver et al, 1986;Slyter and Rumsey, 1991;Russell and Wilson, 1996). In vivo trials also confirmed the influence of pH on microorganisms (Mould et al, 1983;Martin and Michalet-Doreau, 1995).…”

Section: Database Descriptionmentioning

confidence: 84%

Meta-analysis of 0 to 8 h post-prandial evolution of ruminal pH

Dragomir

Sauvant

Peyraud

et al. 2008

Animal

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The objective of this study was to identify relevant descriptors of ruminal pH post-prandial evolution that can replace the mean pH (considered unsatisfactory). These descriptors are to be used in the attempts to predict ruminal pH from dietary characteristics, in order to quantify the potential of a diet to induce subacute ruminal acidosis from its intrinsic characteristics. A total of 219 pH curves, reported as graphics in 48 published articles describing the post-prandial evolution of ruminal pH (first 8 h), were digitized by image analysis then summarized in 15 pH variables. Relationships among pH variables and the principal components (PCs) of pH variability were analyzed in order to identify possible alternatives to mean pH, as the average value of all pH data the curve is composed of. Two groups of pH variables were identified according to their relationship with the most important principal components. A first group, including mean pH, was closely related to PC 1 , which accounted for 78% of data variability; hence, correlations between variables of this group were generally high. Of these, threshold-related variables were distinct as their withinstudy correlations with mean pH were rather moderate (0.69 on average). This suggests they might carry supplementary information that could explain the variation in ruminal pH induced by within-study factors, e.g. diet characteristics. However, caution should be taken in their use because of their truncation at 0 h and their non-normal distribution. Variables from the second group were independent of the PC 1 , and thus of the first group of variables, whereas they were mostly related to PC 2 and PC 3 . This implies they are complementary to mean pH. Of this second group, the rate of pH decreases or the time period when pH reaches its minimum might be useful to better describe the ruminal status, from the point of view of the risk of subacute ruminal acidosis.

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Associative effects of mixed feeds. I. effects of type and level of supplementation and the influence of the rumen fluid pH on cellulolysis in vivo and dry matter digestion of various roughages

Cited by 452 publications

References 15 publications

Influence of pH on lipolysis and biohydrogenation of soybean oil by rumen contents in vitro

Influence of pH on lipolysis and biohydrogenation of soybean oil by rumen contents in vitro

Associative effects between forages on feed intake and digestion in ruminants

Meta-analysis of 0 to 8 h post-prandial evolution of ruminal pH

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