Comparative ingestive mastication in domestic horses and cattle: a pilot investigation

Abstract

It is often assumed that horses chew food more intensively during ingestion than cattle, which - as ruminants - complete part of the mastication during rumination. This has been proposed as a reason for more robust mandibles, larger masseter insertion areas and larger masseter muscles in horses as compared to cattle and other grazing ruminants. In this study, we evaluate results of comparative feeding trials with three horses (338-629 kg) and three cows (404-786 kg), on four different roughages. Ingestion time (s/g dry matter) and chewing intensity (chews/g dry matter) differed among animals within a species, indicating an influence of body mass, and differed significantly between different forages. However, although numerical differences clearly suggest that horses have longer ingestion times and higher chewing intensities on high-fibre roughage than do cattle, this could not be proven in this dataset, most likely because of the small number of individuals sampled. Further studies are required to corroborate the suspected ingestive behaviour difference between equids and ruminants.

How does gut passage impact endozoochorous seed dispersal success? Evidence from a gut environment simulation experiment

“…A second set of seeds were scarified using a 154 cattle skull with the original teeth (treatment "MC"). On average the mastication intensity for cattle 155 is 3.61 chews/g dry matter (Janis, Constable, Houpt, Streich & Clauss 2010), while Erlinger, Tolleson & 156 Brown (1990) calculated that cattle consume on average 0.57g of dry matter per bite. Combining 157 both figures, seeds were chewed twice using a cattle skull.…”

“…A c c e p t e d M a n u s c r i p t 8 dry matter (Janis et al 2010) and according to Fleurance, Fritz, Duncan, Gordon, Edouard et al (2009) 160 the intake rate (IR) can be defined by: 161…”

Mechanical modelling of tooth wear

“…Unlike other artificial chewing studies, our experiment had the teeth do about 100 000 chews. Using data on chewing per gram dry matter, as depending on diet neutral detergent fibre (NDF) [44] and the daily dry matter intake linked to a specific diet NDF [45], a 500 kg horse would reach 100 000 chews within a range of 3.4-5.4 days. Owing to the specific arrangement of initial polishing striations to the chewing direction in the machine, we could also visualize and calculate how many of these initial polishing scratches were still observable on the 0.4 Â 0.4 mm 2 area after 100 000 chews.…”

Applying tribology to teeth of hoofed mammals

“…In ruminants, forage is not chewed extensively during ingestion (reviewed in Janis et al 2010); the majority of particle size reduction in ruminants does not take place during ingestive chewing but during rumination (McLeod and Minson 1988). Ruminants and camelids are characterized by a unique sorting mechanism in their forestomach, which selectively retains large particles, and leads to their regurgitation and further communition via rumination .…”