Ingesta particle size, food handling and ingestion in the tammar wallaby (Macropus eugenii Desmarest)

The particle size distribution of stomach contents from 25 tammar wallabies (Macropus eugenii Desmarest) shot in the Okataina State Forest and adjoining farmland near Rotorua, New Zealand, were determined. There was a greater percentage of finer, and a smaller percentage of larger, particles than reported in the stomach contents of larger macropods. The chewing and biting activities of four free-ranging tammars fitted with radio-microphone collars were monitored. Chewing rates (chews per minute) were similar to those of other small herbivorous vertebrates. There were significantly lower rates of chewing and higher chew-to- bite ratios when browsing than when grazing. Observations of browsing by three captive tammars showed inefficient handling by mutually opposed palms and digitopalmar grip, resulting in low rates of ingestion. We suggest that tammars lower the time necessary for fermentation of food by reducing the size of food particles, and that their choice between graze and browse is influenced by food handling and chewing investment.

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Temporal aspects of feeding events in tammar (Macropus eugenii) and parma (Macropus parma) wallabies. I. Food acquisition and oral processing

Australian Journal of Zoology ◽

10.1071/zo02043 ◽

2004 ◽

Vol 52 (1) ◽

pp. 81 ◽

Cited By ~ 2

Author(s):

R. G. Lentle ◽

I. D. Hume ◽

K. J. Stafford ◽

M. Kennedy ◽

B. P. Springett ◽

...

Keyword(s):

Dry Matter ◽

Tammar Wallaby ◽

Dry Matter Intake ◽

Food Acquisition ◽

Macropus Eugenii ◽

Temporal Aspects ◽

In Captivity ◽

The Mean ◽

Oral Processing ◽

Free Ranging

We studied parameters that influence the efficiency of food acquisition and oral processing in the tammar wallaby (a grazer) and the parma wallaby (a grazer/browser), both in captivity and under free range on Kawau Island, New Zealand.In captivity, both species spent less time feeding per gram of dry matter intake when browsing than when grazing, and there were no significant differences between the species with respect to the rates of feeding per gram of dry matter intake of a given food. However, under free-ranging conditions, tammar wallabies spent longer feeding than did parma wallabies, so it was likely that tammar wallabies spent more time grazing than browsing. Differences in the relationships between feeding event and inter-feed interval duration in captive and free-ranging wallabies indicated that feeding behaviour was influenced by different factors in the two situations.Microtemporal analysis of the chewing sounds of free-ranging tammar and parma wallabies showed that the interval between the first and second sounds in a 'run' of chewing sounds was longer than that between subsequent intervals, indicating that there was a time cost associated with food aquisition. However, as there were no significant differences between the two wallaby species, either in the mean duration of 'runs' of chewing sounds within feeding events or in the mean duration of whole feeding events, this cost was similar for grazing and browsing. Chewing characteristics differed from those of larger (eutherian) herbivores in that the numbers of chews in a run were not randomly distributed, both species having a preponderance of runs with seven chews. Whilst, the intervals between the second and subsequent chewing sounds in a run did not vary in a periodic manner, such as would occur in batch processing of food, they were more prolonged in runs with more chewing sounds and were significantly longer in tammar wallabies than in parma wallabies. Thus, the slower rate of oral processing of grass was likely due to a generally slower rate of chewing when grazing than when browsing.

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Observations on fresh forage intake, ingesta particle size and nutrient digestibility in four species of macropod

Australian Journal of Zoology ◽

10.1071/zo02032 ◽

2003 ◽

Vol 51 (6) ◽

pp. 627 ◽

Cited By ~ 8

Author(s):

R. G. Lentle ◽

I. D. Hume ◽

K. J. Stafford ◽

M. Kennedy ◽

B. P. Springett ◽

...

Keyword(s):

Particle Size ◽

Fine Particles ◽

Tammar Wallaby ◽

Nutrient Digestibility ◽

Size Distributions ◽

Particle Size Distributions ◽

Tooth Morphology ◽

In The Wild ◽

Oral Processing ◽

Free Ranging

The particle-size distributions of the ingesta of the sacciform forestomach in free-ranging animals of a grazing macropod species [Macropus eugenii (tammar wallaby)], a grazer/browser [Macropus parma (parma wallaby)], a browser/grazer [Petrogale penicillata (brush-tailed rock-wallaby)] and a browser [Wallabia bicolor (swamp wallaby)] from Kawau Island, New Zealand, were compared with those of captive animals maintained on a standing ryegrass (Lolium perenne) sward. Nutrient digestibility was also measured in tammar and parma wallabies fed ryegrass or browse, i.e. fresh mahoe (Melicytus ramiflora) and this was related to particle-size distributions of the ingesta.There were significant differences in the particle size distributions of digesta from tammar and parma wallabies in the wild but not in captivity. In free-ranging animals the ingesta from both browsing species, the brush-tailed rock-wallaby and the parma wallaby, contained consistently greater proportions of coarse particles and smaller proportions of fine particles than did those of the tammar wallaby. These differences may be correlated with reported differences in their tooth morphologies. However, the presence of significant differences in particle-size distributions of the digesta between brush-tailed rock-wallabies and parma wallabies when constrained to grass, despite reported similarities in their tooth morphology, suggests that factors other than tooth morphology contribute to differences in the oral processing of food by browsing and grazing macropods. There were greater proportions of grass fragments in the coarse than in the finer fractions of ingesta from free-ranging brush-tailed rock-wallabies, indicating that this species is less effective at chewing grass.There were no overall differences between tammar and parma wallabies in the digestibilities of organic matter, neutral-detergent fibre (NDF) or acid-detergent fibre (ADF) but the NDF and ADF digestibilites of both species increased significantly with increase in the proportion of fine ingesta particles and with increase in mass of fermentative digesta.These findings indicate the importance of oral processing to digestive efficiency in macropods and the relationship between oral processing and tooth morphology.

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Changes in the physical properties of stomach digesta during fasting in tammar wallabies (Macropus eugenii eugenii)

Australian Journal of Zoology ◽

10.1071/zo07055 ◽

2007 ◽

Vol 55 (6) ◽

pp. 383 ◽

Cited By ~ 4

Author(s):

R. G. Lentle ◽

K. J. Stafford ◽

Y. Hemar ◽

P. Aseruvujanon ◽

D. J. Mellor ◽

...

Keyword(s):

Particle Size ◽

Fine Particles ◽

Relative Proportion ◽

Elastic Solid ◽

Fluid Phase ◽

Tammar Wallaby ◽

Matter Content ◽

Dry Matter Content ◽

Macropus Eugenii ◽

Sheep Rumen

We compared changes in the particle size profiles, permeability and elastic shear modulus of digesta in the forestomach and rumen of fasting tammar wallabies (Macropus eugenii eugenii) and fistulated sheep respectively that had been fed chopped lucerne hay. The wet mass of digesta in the tammar wallaby stomach declined curvilinearly over 24 h. The relative proportion of particles >2 mm in size in tammar wallaby digesta increased significantly and that of particles <2 mm in size decreased significantly after 12 h of fasting. This contrasted with the sheep rumen digesta, in which the relative proportions of coarse and fine particles did not change significantly over time. The permeability of wallaby digesta increased significantly after 24 h whilst that of sheep declined. All samples of tammar digesta had a significant elastic component (G′) that was preserved throughout the period of fasting. Interaction between component particles was significant at all times, digesta behaving as a weak gel. The ratio of energy lost to energy stored during flow of digesta tended to decrease during the period of fasting, indicating an increase in behaviour as an elastic solid. The relationship between G′ and dry matter content and mean particle size indicated that these phenomena resulted from progressive loss of finer digesta particles and that digestion in the wallaby stomach, via permeation of the particulate by the fluid phase, was possible for up to 33 h after eating.

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