The Sound of Chewing

Acoustic biotelemetry has been proposed as a way to count ingestive bites and chews of grazing animals. Recent work has indicated the possibility that detailed analysis of \u27sounds of chewing\u27 contains information about other characteristics of the ingestive process that can be used to study grazing behaviour of free ranging animals (Laca & Wallis DeVries, 2000), or to monitor stall-fed animals in more detail

Testing predictions on body mass and gut contents: dissection of an African elephant Loxodonta africana Blumenbach 1797

The values reported in the literature for the total gastrointestinal tract (GIT) content mass of elephants are lower than expected from interspecific mammalian regression. This finding agrees with theoretical considerations that elephants should have less capacious GITs than other herbivorous mammals, resulting in short ingesta retention times. However, the data on elephants was so far derived from either diseased zoo specimens or free-ranging animals subjected to an unknown hunting stress. In this study, we weighed the wet contents of the GIT segments of a captive African elephant that was euthanased because of a positive serological tuberculosis test, but that was clinically healthy, did not show a reduced appetite, and ingested food up to the time of euthanasia. The animal weighed 3,140 kg and its total gut contents were 542 kg or 17% of body mass. This is in close accord with the published mammalian herbivore regression equation of Parra (Comparison of foregut and hindgut fermentation in herbivores. In: Montgomery GG (ed) The ecology of arboreal folivores. Smithsonian Institution Press, Washington DC, pp205-230, 1978) and contradicts the notion that elephants have comparatively less capacious gastrointestinal tracts. Data on the individual gut segments, however, do support earlier suspicions that elephants have a comparatively less capacious caecum and a disproportionally capacious colon

How diverse is the diet of adult South Africans?

The original publication is available at http://www.nutritionj.com/content/10/1/33Abstract. Background. The objective of the current study was to measure dietary diversity in South Africans aged 16 years and older from all population groups as a proxy of food security. Methods. A cross-sectional study representative of adults from all specified ages, provinces, geographic localities, and socio-economic strata in South Africa was used (n = 3287). Trained interviewers visited participants at their homes during the survey. Dietary data was collected by means of a face validated 24 hour recall which was not quantified. A dietary diversity score (DDS) was calculated by counting each of 9 food groups. A DDS <4 was regarded as reflecting poor dietary diversity and poor food security. Results The provinces with the highest prevalence of poor dietary diversity (DDS <4) were Limpopo (61.8%) and the Eastern Cape (59.6%). By contrast, only 15.7% of participants in Western Cape had a low score. Participants in tribal areas (63.9%) and informal urban areas (55.7%) were by far the worst affected. There were significant differences in DDS by Living Standards Mean (LSM) analysis (p < 0.05) with the lowest LSM group having the lowest mean DDS (2.93).The most commonly consumed food groups were cereals/roots; meat/fish; dairy and vegetables other than vitamin A rich. Eggs, legumes, and vitamin A rich fruit and vegetables were the least consumed. Conclusion. Overall the majority of South Africans consumed a diet low in dietary variety. The tribal areas and informal urban areas were worst affected and eggs, legumes and vitamin A rich fruit and vegetables, were the least consumed.Publishers' versio

Body Size Distribution of the Dinosaurs

The distribution of species body size is critically important for determining resource use within a group or clade. It is widely known that non-avian dinosaurs were the largest creatures to roam the Earth. There is, however, little understanding of how maximum species body size was distributed among the dinosaurs. Do they share a similar distribution to modern day vertebrate groups in spite of their large size, or did they exhibit fundamentally different distributions due to unique evolutionary pressures and adaptations? Here, we address this question by comparing the distribution of maximum species body size for dinosaurs to an extensive set of extant and extinct vertebrate groups. We also examine the body size distribution of dinosaurs by various sub-groups, time periods and formations. We find that dinosaurs exhibit a strong skew towards larger species, in direct contrast to modern day vertebrates. This pattern is not solely an artefact of bias in the fossil record, as demonstrated by contrasting distributions in two major extinct groups and supports the hypothesis that dinosaurs exhibited a fundamentally different life history strategy to other terrestrial vertebrates. A disparity in the size distribution of the herbivorous Ornithischia and Sauropodomorpha and the largely carnivorous Theropoda suggests that this pattern may have been a product of a divergence in evolutionary strategies: herbivorous dinosaurs rapidly evolved large size to escape predation by carnivores and maximise digestive efficiency; carnivores had sufficient resources among juvenile dinosaurs and non-dinosaurian prey to achieve optimal success at smaller body size. © 2012 O'Gorman, Hone

The Use of a Portable Computer for Real-Time Recording of Observations of Grazing Behavior in the Field

A real-time system for recording grazing behavior in the field is described. A NEC 8201a portable computer was programmed to allow the incidence, duration, and sequence of behaviors to be recorded. This system was used in the field to record bites, chews, steps, and swallows of grazing cattle. Data files were analyzed to determine biting, stepping, and swallowing rates as well as bites per feeding station. Durations of all activities can be summarized. This system permits the observer to record accurately feeding behavior and reduce significantly the time and cost of processing data.This material was digitized as part of a cooperative project between the Society for Range Management and the University of Arizona Libraries.The Journal of Range Management archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform August 202

Spatial–temporal arrangements of supplementation to modify selection of feeding sites by sheep

Undesirable grazing distribution results in land degradation and inefficient forage utilization. Rewards like food supplements have been commonly provided at predictable times and locations in the less preferred areas in order to improve grazing distribution. The problem with this approach is the generation of search patterns that are concentrated at certain times and locations, causing either overgrazing of new areas or the rapid return of the animals to the most preferred areas. Our model of spatial–temporal schedule of reinforcement proposes that rewards that are unpredictable in space and time should promote search patterns that are extended in space and time. In order to test predictions from the model, we studied how the spatial–temporal arrangement of supplementation influenced selection of feeding sites by sheep on a grass-legume pasture. Each experimental plot had a fertilized and an unfertilized side (8 m × 16 m each) either adjacent (Trial 1) or separated by an alley (1 m × 32 m) (Trial 2). In both trials groups of three ewes were randomly assigned to each of four treatments resulting from the combination of two spatial and two temporal arrangements of supplementation in the unfertilized side of the pasture. All treatments received the same amount and type of supplement (500 g alfalfa/corn pellets per ewe per day). There were two repetitions per treatment. Animal positions were recorded every 2 min during 2 h daily grazing sessions for 12 (Trial 1) or eight (Trial 2) consecutive days. The response variable was the proportion of time spent on the unfertilized side of the pasture. In Trial 1 neither treatment effects nor the interaction treatment by day was significant (P > 0.05). In Trial 2, the random spatial and/or temporal arrangements of supplementation tended to increase the occupation of the unfertilized side of the pasture by sheep. The differences among treatments were larger at the beginning of the trial, when the availability of forage was relatively higher than towards the end of the trial, when the availability of forage was relatively lower. In both trials the proportion of time spent on the unfertilized side of the pasture decreased (P < 0.01) as the daily grazing session progressed from the first half hour to the second half hour to the last hour. Our results raise some interesting possibilities that warrant future tests of the model of spatial–temporal schedule of reinforcement to modify selection of feeding sites by free grazing animals.Fil: Distel, Roberto Alejandro. Universidad Nacional del Sur. Departamento de Agronomía; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; ArgentinaFil: Soca, P. M.. Facultad de Agronomía ; UruguayFil: Demment, M. W.. University of California at Davis; Estados UnidosFil: Laca, E. A.. University of California at Davis; Estados Unido

Comparison of weight estimate and rising-plate meter methods to measure herbage mass of a mountain meadow

A rising plate meter (RPM) and ocular estimation of herbage fresh weight (OCES) were compared as double sampling methods to measure herbage dry weight (DWT) in a mountain meadow grazed by cattle (0, 2.5, 3.2, and 6.9 AUM/ha) and deer. On 8 dates, 5 to 10 plots were clipped and 50 to 100 plots were estimated in 2 or 4 pastures, each of which had 6 vegetation types, resulting in 120 groups of observations. Whereas 11 different calibration lines were necessary to calibrate the OCES (r2 =0.74$ to 0.91), 17 lines were needed for the RPM (r2=0.04 to 0.82). Average residual standard deviations (Sy.x) were 653 for OCES vs. 846 kg ha-1 for RPM. The different calibrations for OCES were caused by differences in the %DM of the herbage (dates and meadow type), whereas RPM calibrations were affected by grazing treatment, date, meadow type, and observer. When the same number of clipped and estimated plots were used for both methods, OCES was 24% more precise than RPM. To obtain a precision of +/- 200 kg ha-1 (P=0.05) OCES required 697 fewer clipped plots for the whole experiment than RPM, but OCES field costs were 3% higher. If calibrated on net readings (before-after clipping) RPM overestimated herbage mass, relative to clipped plots and OCES. The lower cost per RPM reading was counterbalanced by greater precision and generality of OCES calibrations.This material was digitized as part of a cooperative project between the Society for Range Management and the University of Arizona Libraries.The Journal of Range Management archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform August 202