The Influence of Saliva on Digestion in Ruminants

Kay, R. N. B.

doi:10.1159/000391428

Cited by 94 publications

(73 citation statements)

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“…C4. Differences in fracture patterns of grass and browse have been noted (Spalinger et al 1986;Kay 1993;Van Wieren 1996a). Several authors have reported more polygonal particles from herbaceous forage leaves and more longish particles from grass leaves (Troelsen and Campbell 1968;Moseley and Jones 1984;Mtengeti et al 1995).…”

Section: Grass and Browsementioning

confidence: 96%

The Morphophysiological Adaptations of Browsing and Grazing Mammals

2008

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(2008). The morphophysiological adaptations of browsing and grazing mammals. In: Gordon, I J [et al.]. The ecology of browsing and grazing. Berlin, 47-88. Postprint available at: http://www.zora.uzh.ch Posted at the Zurich Open Repository and Archive, University of Zurich. http://www.zora.uzh.ch Originally published at: Gordon, I J [et al.] 2008. The ecology of browsing and grazing. Berlin, 47-88. The morphophysiological adaptations of browsing and grazing mammals AbstractThere has been a continous debate whether there are fundametal morphophysiological differences in the ingestive apparatus (head, teeth) and the digestive tract between browsing and grazing herbivores. A particular characteristic of this debate appears to be that while there is a wealth of publications on such potential differences, the supposed undelying differences between browse and grass have rarely been analysed quantitatively. In this chapter, we first review the actual state of knowledge on those properties of browse and grass that appear relevant for the ingestive and digestive process, and then deduct hypotheses as to how one would assume that browsers and grazers differ due to these characteristics. We address the methodological issues involved in actually testing these hypotheses, with emphasis on the influence of body mass and phylogenetic descent. Finally, we present a literature compilation of statistical tests of differences between the feeding-types. Although in general, the published tests support many hypothesized differences, there is still both a lack of comparative data, and a lack of analyses with phylogenetic control, on different taxonomic levels. However, the published material appears to indicate that convergent evolutionary adaptations of browsing and grazing herbivores to their diet represent a rewarding area of research. The Morphophysiological Adaptations of Browsing and Grazing MammalsMarcus Clauss, Thomas Kaiser, and Jürgen Hummel IntroductionAnimals represent adaptations to particular ecological niches they occupy or once occupied.Studying the correlation between a given set of characteristics of an ecological niche and the morphological and physiological adaptations of organisms to these characteristics is one of the most basic approaches to comparative biology, and has fuelled scientific interest for generations (Gould 2002). However, current scientific standards cannot be met by mere descriptions of both the characteristics of the niche and the organism, and a (hypothetical) intuitive explanation for the adaptive relevance of the latter; the presence or absence of a characteristic must be demonstrated in sound statistical terms (Hagen 2003) 1 ideally supported by experimental data (from in vivo, in vitro, or model assays) on its adaptive relevance.In this chapter, we adopt an approach that first presents the relevant characteristics of the ecological niche of the 'grazer' (GR) and of the 'browser' (BR), outlines hypotheses based on these characteristics, and finally addresses examples where such hypotheses h...

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Section: Grass and Browsementioning

confidence: 96%

The Morphophysiological Adaptations of Browsing and Grazing Mammals

2008

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“…In contrast, Surra et al (1997a) using Co-EDTA as a marker of salivary flow, reported that losses in saliva accounted for only 0.001 of urinary PD excretion. Large discrepancies between estimates of purine losses via saliva are difficult to reconcile, since these large differences cannot be satisfactorily explained by dietary induced variations (Kay, 1966) or incorrect assumptions of salivary flow.…”

Section: Salivary Secretionmentioning

confidence: 99%

Estimation of microbial protein supply in ruminant animals based on renal and mammary purine metabolite excretion. A review

Shingfield¹

2000

J. Anim. Feed Sci.

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The potential of mammary and renal purine metabolite excretion as a technique for the assessment of microbial protein supply in ruminant animals is reviewed. Data reported in the literature tends to support the validity of the assumptions of the technique that purines entering the duodenum are essentially microbial in origin and that following metabolism, purine catabolites (collectively allantoin, hypoxanthine, uric acid and xanthine) are quantitatively recovered in urine. The most convincing experimental evidence suggests that secretion of purine metabolites in milk is of little value for the assessment of microbial protein supply due a mumal correlation with milk yield. In contrast, use of urinary purine metabolite excretion does appear to provide estimates of microbial protein supply that, are in general, consistent with values derived using standard in vivo procedures. However, the accuracy of this approach is largely dependent on obtaining representative samples of rumen microbes and the ability to account for variations in non-renal excretion and endogenous purine losses. In conclusion, urinary purine metabolite excretion appears to represent a valid noninvasive procedure to assess relative differences, rather than quantitative estimates of microbial protein supply in ruminant animals.

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“…This observation is in agreement with that of Shackleford and Wilborn (1970) who observed more or less similar structures in bovine submandibular striated duct. In contrast to highly isotonic secretion of bovine parotid glands, the submandibular glands secrete relatively small amounts of hypotonic saliva (Kay, 1966). The marked ductual modifications of striated ducts in this gland may also account for the hypotonic saliva secretion in camel as was-reported by Hoppe and Kay (1974).…”

Section: Resultsmentioning

confidence: 65%

“…Salivary glands of ruminants are extensively different in their structure and function when compared with those of other mammalian species Wilborn, 1969, 1970). Kay (1966) reported that stimulated salivary glands of cattle produce relatively large volume of saliva which is unique to ruminants and corresponds to the variations in the structure of salivary glands. However, no such information on the ultrastructure of salivary glands of camel is yet available, hence present study was undertaken.…”

Section: Introductionmentioning

confidence: 99%