Gross intestinal morphometry and allometry in ruminants.

While some descriptions of ruminants' dietary adaptations suggest that the length of the intestinal tract reflects the proportion of grass or browse in the diet, this assumption has been questioned. We collated data on body mass (BM), as well as small intestine, caecum, colon/rectum, large and total intestine length in 68 ruminant species, and, while accounting for the phylogenetic structure of the dataset, evaluated both allometric scaling and the potential influence of diet, digestive physiology or climate proxies on measures of intestine length. Intestinal length generally scaled to BM at an exponent higher than the 0.

Comparative omasum anatomy in ruminants: Relationships with natural diet, digestive physiology, and general considerations on allometric investigations.

The omasum is the third forestomach compartment of pecoran ruminants. It is assumed that the re-absorption of fluid present in the forestomach digesta (that facilitates particle sorting, digestion, and harvest of microbes) is its main function, so that less diluted digesta is submitted to enzymatic digestion in the lower digestive tract. Here, we evaluate measures of omasum size (representing 84 ruminant species in the largest data set) against body mass and proxies of the natural diet (%grass) or forestomach physiology (fluid throughput), using phylogenetically controlled models.

Convergence of macroscopic tongue anatomy in ruminants and scaling relationships with body mass or tongue length.

Various morphological measures demonstrate convergent evolution in ruminants with their natural diet, in particular with respect to the browser/grazer dichotomy. Here, we report quantitative macroanatomical measures of the tongue (length and width of specific parts) of 65 ruminant species and relate them to either body mass (BM) or total tongue length, and to the percentage of grass in the natural diet (%grass). Models without and with accounting for the phylogenetic structures of the dataset were used, and models were ranked using Akaike's Information Criterion.

The intraruminal papillation gradient in wild ruminants of different feeding types: Implications for rumen physiology.

Browsing and grazing ruminants are thought to differ in the degree their rumen contents are stratified-which may be due to different characteristics of their respective forages, to particular adaptations of the animals, or both. However, this stratification is difficult to measure in live animals. The papillation of the rumen has been suggested as an anatomical proxy for stratification-with even papillation indicating homogenous contents, and uneven papillation (with few and small dorsal and ventral papillae, and prominent papillae in the atrium ruminis) stratified contents.