Bite‐Size Python® | ScienceGate

Increases in portion size lead to increases in energy intake, yet the mechanisms behind this ‘portion size effect’ are unclear. This study tested possible mechanisms of the portion size effect i.e., bite size and visual cues in 30 over- and normal-weight individuals (15 men, 15 women). A 2x2 repeated measures, within-subject design was used to test the effects of portion size (410g vs. 820g of a pasta dish) and visual cues (blindfolded vs. visible) on energy intake. At each meal participants were exposed to one of four experimental conditions (small portion/visible; small portion/blindfold; large portion/visible; large portion/blindfold). Participant characteristics, food intake, number of bites, meal duration, palatability measures and hunger and fullness were assessed. In response to a doubling of the portion presented, entrée energy intake increased 26% (220kcal P < 0.001) and mean bite size increased 2.4g/bite (P < 0.05). Overweight individuals consumed 40% (334kcal) more of the entrée in response to the large portion condition (P < 0.05), while lean individuals’ intakes did not differ (P < 0.56). A 12% (122kcal) decrease in entrée intake was observed in the blindfolded condition (P < 0.01), but no portion by visual cue interaction was found; indicating that blindfolding did not attenuate the portion size effect. These data suggest that the portion size effect is greater in overweight individuals and occurs via changes in bite size.

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Effect of sward structure of two tropical grasses with contrasting canopies on light distribution, net photosynthesis and size of bite harvested by grazing cattle

Australian Journal of Agricultural Research ◽

10.1071/ar9820187 ◽

1982 ◽

Vol 33 (2) ◽

pp. 187 ◽

Cited By ~ 14

Author(s):

MM Ludlow ◽

TH Stobbs ◽

R Davos ◽

DA Charles-Edwards

Keyword(s):

Leaf Area ◽

Growth Regulators ◽

Light Distribution ◽

Trimethylammonium Chloride ◽

Tropical Pastures ◽

Area Density ◽

Tropical Grasses ◽

Bite Size ◽

Leaf Area Density ◽

Grazing Cattle

Our aim was to determine whether increasing the sward density of tropical pastures, for the purpose of enhancing the size of bite harvested by grazing cattle, would reduce yield by affecting light distribution andcanopy photosynthesis. The growth regulators (2-chloroethy1)trimethylammonium chloride (CCC) and gibberillic acid (GA) were used to alter the leaf area density of the tussock-forming grass Setavia sphacelata and of the sward-forming grass Digitaria decumbens. GA increased plant height, the length of stem internodes, and the size of bite harvested by cattle. On the other hand, CCC decreased canopy height, and increased leaf area density and bite size. The variation of leaf area density, investigated experimentally by using growth regulators (5-25 m-1) and theoretically by simulation modelling (5-40 m-1), had no significant effect on either leaf or canopy photosynthetic characteristics. Hence we believe that there would be a negligible reduction in yield of these tropical grasses if their leaf area densities were increased up to a value of 40 m-1, which exceeds those of temperate pastures. Such increases in leaf area density may increase animal production from tropical pastures where bite size limits daily intake of forage. The agricultural implications of the findings are discussed.

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Effect of species composition and sward structure on the ingestive behaviour of cattle and sheep grazing South African sourveld

The Journal of Agricultural Science ◽

10.1017/s0021859600078047 ◽

1996 ◽

Vol 127 (2) ◽

pp. 271-280 ◽

Cited By ~ 9

Author(s):

P. J. O'Reagain ◽

B. C. Goetsch ◽

R. N. Owen-Smith

Keyword(s):

Species Composition ◽

Plant Height ◽

Functional Response ◽

Major Effect ◽

Intake Rate ◽

Sheep Grazing ◽

Bite Size ◽

Ingestive Behaviour ◽

Cattle And Sheep ◽

Sward Structure

SUMMARYThe effects of species composition and sward structure on the ingestive behaviour of cattle and sheep grazing a mesic, low quality grassland in South Africa were investigated over the 1990–93 grazing seasons. Species composition had a significant (P < 0·05) effect on sheep bite size and on cattle and sheep bite rates but had no effect on dry matter intake rate (IR). Species composition could, however, affect IR over longer grazing periods than those used in the experiment.Sward structure had a major effect on ingestive behaviour. Cattle and sheep bite rates and cattle grazing time, were negatively correlated (P < 0·05) with plant height but positively correlated (P < 0·05) with sward greenness. Bite size and hence IR in cattle and sheep were strongly correlated (P < 0·001) with plant height. Cattle IR increased from 6 to 20g/min over the range of heights encountered and appeared to reach an asymptote at a plant height of 20–25 cm. Sheep IR, expressed per unit of body mass, increased from 0·01 to an asymptote or maximum of 0·13 g/min/kg at plant heights of 10–15 cm. For sheep there was evidence of a non-asymptotic functional response at some sites with IR being maximized at certain sward heights but declining thereafter. This suggests the possible existence of a third, quality dimension to the functional response on these low-quality grasslands.

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Offer Bite-Size Involvement

The Membership Management Report ◽

10.1002/mmr.31026 ◽

2018 ◽

Vol 14 (9) ◽

pp. 3-3

Keyword(s):

Bite Size

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Sward height and bite size affect the functional response of barnacle geese Branta leucopsis

Journal of Ornithology ◽

10.1007/s10336-005-0041-5 ◽

2005 ◽

Vol 147 (3) ◽

pp. 479-484 ◽

Cited By ~ 16

Author(s):

Alexandra J. van der Graaf ◽

Pieter Coehoorn ◽

Julia Stahl

Keyword(s):

Functional Response ◽

Bite Size ◽

Sward Height ◽

Barnacle Geese ◽

Branta Leucopsis

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Milk production, milk composition, rate of milking and grazing behaviour of dairy cows grazing two tropical grass pastures under a leader and follower system

Australian Journal of Experimental Agriculture ◽

10.1071/ea9780005 ◽

1978 ◽

Vol 18 (90) ◽

pp. 5 ◽

Cited By ~ 10

Author(s):

TH Stobbs

Keyword(s):

Milk Production ◽

Latin Square ◽

Milk Composition ◽

Panicum Maximum ◽

Tropical Pastures ◽

Rhodes Grass ◽

Bite Size ◽

Leaders And Followers ◽

Jersey Cows ◽

Grazing Behaviour

Milk production, milk composition, rate of milking and grazing behaviour were measured for lactating Jersey cows having both the first opportunity to graze (leaders) and also when offered the remaining herbage (followers) from 3-week regrowths of two nitrogen-fertilized tropical pastures, Rhodes grass (Choris gayana cv. Pioneer) and Gatton panic (Panicum maximum cv. Gatton). Twenty-four cows were used in a latin-square design with experimental periods of 14 days. Both leaders and followers were allocated 40 kg DM cow-1 day-1. Leader cows produced 8.0 kg milk cow-1 day-1 compared with 5.8 kg milk cow-1 day-1 for followers, a difference of 38 per cent. Both leader and follower cows grazing Gatton panic produced more milk than cows grazing Rhodes grass. Milk from leader cows contained a higher percentage of solids-not-fat and protein and a lower butterfat percentage indicating a higher intake of digestible nutrients. Cows showed a preference for leaf, and after easily accessible leaf was removed by leader cows the follower cows had a small bite size. Follower cows partially compensated by increasing grazing time, mainly at night. Follower cows had a longer let-down time and a longer milking time per kilogram of milk produced. Milk production was linearly related to bite size and availability and accessibility of leaf were considered to be the main factors influencing production.

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Further development of the Spalinger-Hobbs mechanistic foraging model for free-ranging moose

Canadian Journal of Zoology ◽

10.1139/z99-119 ◽

1999 ◽

Vol 77 (10) ◽

pp. 1505-1512 ◽

Cited By ~ 8

Author(s):

John Pastor ◽

Katie Standke ◽

Keith Farnsworth ◽

Ron Moen ◽

Yosef Cohen

Keyword(s):

Mechanistic Model ◽

Sequence Length ◽

Intake Rate ◽

Frequency Distributions ◽

Bite Size ◽

Bite Rate ◽

Independent Events ◽

Epilobium Angustifolium ◽

Free Ranging ◽

Further Development

Spalinger and Hobbs proposed a mechanistic model of forage intake based on the mutually exclusive actions of biting and chewing. A necessary consequence of this model is that an animal postpones the intake of more food by biting when it is processing food by chewing. In previous work, the Spalinger-Hobbs model successfully predicted short-term intake in controlled experiments. Application of the model to an entire foraging bout requires the following assumptions: (i) biting and chewing are independent events; (ii) there are no periodicities in the length of consecutive bite or chew sequences; (iii) the average bite size is constant; and (iv) the bite rate does not change with the number of bites in the sequence. To test these assumptions, we videotaped entire foraging bouts of two free-ranging moose (Alces alces) feeding on dense swards of Epilobium angustifolium in midsummer. From these videotapes, we measured the time spent biting and chewing, the rates of biting and chewing, the frequency distributions of consecutive bite and chew sequences, and lengths of E. angustifolium shoots above the point of cropping. Plant samples were collected in order to determine bite mass. A total of 1050 bites and chews were analyzed for moose 1 and 1925 bites and chews for moose 2. For both moose, three chewing events occurred, on average, for each bite event. Given this 1:3 bite:chew ratio, the frequency distributions of consecutive bite and chew sequences were as expected from a geometric distribution of independent events. There were no time-series correlations or dominating frequencies in the lengths of bite and chew sequences. These findings fulfill the first three assumptions required to extend the Spalinger-Hobbs model to entire foraging bouts. However, the fourth assumption was not fulfilled, in that time spent per bite increased asymptotically with bite-sequence length. We therefore incorporated the effect of bite-sequence length on bite rate into the Spalinger-Hobbs model. The new model predicts that to simultaneously maximize the marginal intake rate with respect to both bite rate and bite mass, a moose should take single bites most often and bite mass should be approximately 3.6 g. Eighty-two percent of bite sequences were composed of single bites for both moose, and we and others independently observed a bite size of 3.24-3.75 g for free-ranging moose. These observations lend credibility to our modified model.

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