Feeding behaviour feedback signals ruminant gastrointestinal tract metabolites and hormones central nervous control integrative theories of food intake control growth and fattening reproduction and lactation diet digestability and concentration of available energy specific nutrients affecting intake learning about food - preferences diet selection appetites for specific nutrients environmental factors affecting intake the intake of fresh and conserved grass prediction of voluntary intake. Appendices: particular features of poultry and ruminant animals outline programme to identify and store meals from the identities of animals and weights of food containers.

Voluntary food intake and diet selection in farm animals.

This article examines how the depletion and replenishment of various energy stores give rise to periodic eating and how constant body-energy levels are maintained over time.Measures of the energy expended throughout the 24-hour feeding pattern in rats indicate that two different energy stores (one of small capacity and one of large) determine two superimposed feeding periodicities: one from meal to meal (prandial), the other from day to night (nycthemeral). The article reviews how experimental overrepletion or overdepletion of gastrointestinal content, blood glucose, or body fats affect food intake. These data suggest that gastrointestinal content determines both meal size and meal-to-meal periodicity. Other evidence indicates that glucose uptake rate in tissues, which is modulated by fat synthesis and fat mobilization, affects the periodic onset of feeding and the difference between nocturnal and diurnal postprandial satiety.There follows an examination of the neuroendocrine bases for the interacting mechanisms governing energy input and output balance and of the role of the ventromedial hypothalamus in body-fat regulation and the lateral hypothalamus in feeding.

The metabolic basis of dual periodicity of feeding in rats

Food intake patterns of growing pigs given food ad libitum in individual and group housing were derived from food intake recordings with IVOG®-stations. The IVOG-station is a feeding station that records animal identification number, time, duration and amount of food intake during each visit of a pig to the food hopper. Data were collected in three testing batches of 90 Dutch Landrace pigs each, housed in 10 individual pens and in 10 group pens of eight pigs per batch.Based on survival analysis theory, intervals between visits shorter than 5 min (which was used as meal criterion) were regarded as within-meal intervals and these visits were grouped into meals. In group housing, food intake per day and rate of food intake had no significantly non-normal distribution. In individual housing, rate of food intake, food intake per day and number of meals per day had no significantly non-normal distribution. In individual housing rate of food intake, food intake per day and number of meals per day had no significantly non-normal distribution. All traits were normally distributed after discarding extreme values, except food intake and eating time per visit and per meal. In group housing these traits were not significantly non-normally distributed after logarithmic transformation.Pigs housed in groups ate faster, had a higher food intake per meal but less meals per day, less eating time per day and a lower daily food intake than pigs penned individually. During the day two peaks of feeding activity occurred, especially in group housing: one in the morning and one in the beginning of the afternoon.A distinction was made between meals with a major contribution to daily food intake and meals of minor importance. In group housing, 69% of the daily number of meals accounted for proportionately 0·87 of daily food intake and 0·83 of daily food intake time. In individual housing 39% of the meals accounted for proportionately 0·90 of the daily food intake and 0·79 of the daily eating time.Higher repeatabilities of day to day recordings of food intake traits, were found when estimated within 2-week periods compared with months or with the total fattening period.

Patterns of daily food intake in growing pigs

Feeding and drinking patterns in young pigs

Optimization theory is applied to hummingbird foraging to explain the observation that birds in the laboratory with access to functionally unlimited food supplies usually do not take as large a meal as they could. Foraging bouts are modeled in terms of time and energy; birds are constrained by the increased energetic costs associated with the added weight of their meal. Predictions of optimal meal size which maximize the rate of net energy gain or which maximize efficiency agree closely with laboratory and limited field data; we presently are unable to discriminate between these two optimality criteria. Predictions which assume optimal use of time or which maximize net energy gain or which neglect weight of the meal all proved unsatisfactory, generally by predicting optimal meal sizes in excess of capacity. Sensitivity analysis revealed that model predictions may be much influenced by parameter values potentially under physiological and/or behavioral control by a hummingbird. While we presently do not und...

A.R. Horne

Papers

The pattern of food intake in female Brown Leghorn fowls as recorded in a Skinner box