Weights of salivary glands in some ruminant animals

Kay, R. N. B.

doi:10.1111/j.1469-7998.1987.tb01544.x

Cited by 40 publications

(36 citation statements)

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“…These data and the data for 10 other African browsers extracted from their data list, and defined as browsers by having 10% or less grass in their diets, are shown in Table 3. They show that gland mass declines as body mass increases, and confirm that it correlates well with metabolic rate as proposed by Kay (1987) and Hofmann et al (2008). If so it will be small in large browsers.…”

Section: Discussionsupporting

confidence: 64%

“…In giraffe it varies with browse height (Young & Isbell, 1991), bite size varies between 2.5 (Pellew, 1984B) to 0.5 grams per bite (Young & Isbell, 1991) and they take 15-30 bites a minute (Pellew, 1984A;Young & Isbell, 1991). Kay (1987) found that feeding increased secretion rate 4-fold in goats and Robbins et al (1995) measured a secretion rate of 3-16ml/gramDM intake in a browser. Applying these rates to giraffes, their parotid gland could secrete between 1.1±0.2 and 3.2±1.5 ml of saliva per gram of gland per minute while they are browsing (Table 2A).…”

Section: Discussionmentioning

confidence: 99%

“…The size of the glands in giraffes (and okapi), which is relatively far smaller than in any other ruminant, clearly has a genetic component and perhaps an epigenetic one as it may be affected by the consistency of the diet with diets providing mechanical stimulation leading to hypertrophy (Kay, 1987), by the volume of saliva produced (Hofmann, 1989), by the amount of tannin neutralizing proteins secreted (Robbins et al, 1995), and /or variation in habitat, variation with seasons, increasing in summer and regressing in winter, and dissection technique . Hofmann et al also suggested that the small parotid gland in okapi and giraffes could be complemented by comparatively large mandibular, buccal and sublingual glands.…”

Section: Discussionmentioning

confidence: 99%

“…Saliva secretion rate is stimulated by eating (Kay, 1987) and varies with dry matter intake and bite size (Robbins et al, 1995). In giraffe it varies with browse height (Young & Isbell, 1991), bite size varies between 2.5 (Pellew, 1984B) to 0.5 grams per bite (Young & Isbell, 1991) and they take 15-30 bites a minute (Pellew, 1984A;Young & Isbell, 1991).…”

Section: Discussionmentioning

confidence: 99%

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The digestive morphophysiology of wild, free-living, giraffes

Mitchell

Roberts

Sittert

2015

Comparative Biochemistry and Physiology Part A: Molecular &

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We have measured rumen-complex (rumen, reticulum, omasum, abomasum) and intestine (small and large combined) mass in 32 wild giraffes of both sexes with body masses ranging from 289 -1441kg, and parotid gland mass, tongue length and mass, masseter and mandible mass in 9 other giraffes ranging in body mass from 181 to 1396kg. We have estimated metabolic and energy production rates, feed intake and home range size. Interspecific analysis of mature ruminants show that components of the digestive system increase linearly (Mb 1 ) or positively allometric (Mb >1 ) with body mass while variables associated with feed intake scale with metabolic rate (Mb .75 ). Conversely, in giraffes ontogenetic increases in rumen-complex mass were negatively allometric (Mb <1 ), and increases in intestine mass, parotid gland mass, masseter mass, and mandible mass were isometric (Mb 1 ). The relative masseter muscle mass (0.14% of Mb) and the relative parotid mass (0.03% of Mb) are smaller than in other ruminants. Increases in tongue length scale with head length 0.72 and Mb .32 and tongue mass with Mb .69 . Absolute mass of the gastrointestinal tract increased throughout growth but its relative mass declined from 20% to 15% of Mb. Rumen-complex fermentation provides ca43% of daily energy needs, large intestine fermentation 24% and 33% by digestion of soluble carbohydrates, proteins, and lipids. Dry matter intake (kg) was 2.4 % of body mass in juveniles and 1.6% in adults.Energy requirements increased from 35Mj/day to 190 Mj/day. Browse production rate sustains a core home range of 2.2-11.8 km 2 .

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Section: Discussionsupporting

confidence: 64%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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The digestive morphophysiology of wild, free-living, giraffes

Mitchell

Roberts

Sittert

2015

Comparative Biochemistry and Physiology Part A: Molecular &

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“…In order to counteract plant secondary compounds, it has been suggested that BR produce salivary proteins that bind to these compounds. See Clauss (2003) and Shimada (2006) for reviews of species in which such proteins have been demonstrated; however, the number of species investigated thus far makes a statistical comparison between BR and GR unfeasible.Supposedly larger salivary glands of BR ruminants (Kay et al 1980;Kay 1987b;Hofmann 1988) have been considered to be a morphological correlate of a high production of these salivaryproteins ( Hypsodonty (as an adaptation to increased tooth wear due to abrasion and maybe increased attrition; C.3) has been observed in many GR groups such as marsupials, rodents, lagomorphs, and ungulates (Simpson 1953;Fortelius 1985;Janis and Fortelius 1988). Experimental work on the influence of crown height on survival is summarised in Williams and Kay (2001).…”

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confidence: 99%

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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Convergent evolution in feeding types: Salivary gland mass differences in wild ruminant species

Hofmann

Streich

Fickel

et al. 2007

Journal of Morphology

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In the ongoing debate about divergent evolutionary morphophysiological adaptations of grazing and browsing ruminants, the size of the salivary glands has received special attention. Here, we report the most comprehensive dataset on ruminant salivary glands so far, with data on the Glandula parotis (n=62 species), Gl. mandibularis (n=61), Gl. buccalis ventralis (n=44), and Gl. sublingualis (n=30). All four salivary gland complexes showed allometric scaling with body mass (BM); in all cases, the 95% confidence interval for the allometric exponent included 0.75 but did not include 1.0 (linearity); therefore, like other parameters linked to the process of food intake, salivary gland mass appears to be correlated to metabolic body weight (BM0.75), and comparisons of relative salivary gland mass between species should rather be made on the basis of BM0.75 than as a percentage of BM. In the subsequent analyses, the percentage of grass (%grass) in the natural diet was used to characterize the feeding type; the phylogenetic tree used for a controlled statistical evaluation was entirely based on mitochondrial DNA information. Regardless of phylogenetic control in the statistical treatment, there was, for all four gland complexes, a significant positive correlation of BM and gland mass, and a significant negative correlation between %grass in the natural diet and gland mass. If the Gl. parotis was analyzed either for cervid or for bovid species only, the negative correlation of gland mass and %grass was still significant in either case; an inspection of certain ruminant subfamilies, however, suggested that a convergent evolutionary adaptation can only be demonstrated if a sufficient variety of ruminant subfamilies are included in a dataset. The results support the concept that ruminant species that ingest more grass have smaller salivary glands, possibly indicating a reduced requirement for the production of salivary tannin-binding proteins.

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Weights of salivary glands in some ruminant animals

Cited by 40 publications

References 6 publications

The digestive morphophysiology of wild, free-living, giraffes

The digestive morphophysiology of wild, free-living, giraffes

The Morphophysiological Adaptations of Browsing and Grazing Mammals

Convergent evolution in feeding types: Salivary gland mass differences in wild ruminant species

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