Studies of the food intake of sheep at a single meal

Ternouth, J. H.; Beattie, A. W.

doi:10.1079/bjn19710073

Cited by 43 publications

(18 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, it can be said that most theories of satiety relate it primarily to the volume and physical and chemical composition of the food in the gut (Baile, 1968). The exception is that of Ternouth & Beattie (1971) who relate satiety in sheep, in part, to changes in plasma osmolarity consequent upon fluid shifts into the gut at feeding time.…”

Section: Discussionmentioning

confidence: 99%

Changes during eating in oxygen consumption, cardiac function and body fluids of sheep

Christopherson¹,

Webster²

1972

The Journal of Physiology

View full text Add to dashboard Cite

3. Arterial Po. did not change significantly during eating. However PV 02 fell slightly but significantly. The 02 saturation of venous blood fell due to the decline in pH. Estimated CO2 in arterial blood increased as a consequence of increased haemoglobin content. The net effect was to increase arteriovenous difference in 02 content from 4-4 ml./100 ml. before eating to 6-0 ml./100 ml. at the end of the meal.4. 02 consumption increased about 60 % during eating and fell rapidly thereafter. Heart rate followed a similar pattern. Cardiac output however increased only about 17 %, from 6 to 7 1./min. Consequently stroke volume declined throughout the meal from 76 to 52 ml./beat.5. Plasma volume, estimated from measurements of T-1824, declined sharply by about 300 ml. at the beginning of the meal and recovered slowly after feed was removed. Blood volume declined less because of a rise in circulating erythrocytes.6. Extracellular fluid volume was estimated from measurements of thiocyanate and thiosulphate spaces. Thiocyanate space measurements were abandoned after thiocyanate was found to be concentrated in saliva.Considerable random variation occurred in measurements of changes in extracellular fluid from thiosulphate disappearance but the results did

show abstract

Section: Discussionmentioning

confidence: 99%

Changes during eating in oxygen consumption, cardiac function and body fluids of sheep

Christopherson¹,

Webster²

1972

The Journal of Physiology

View full text Add to dashboard Cite

show abstract

“…On the one hand, intraruminal infusion of sodium acetate solutions depresses intake more than equimolar amounts of sodium chloride both in sheep 21 and in cows 22 . On the other hand, the effects of salt infusions into the rumen on feed intake are very much less when access to water is allowed, compared with when water is withheld 23,24 , and it is to be noted that Carter & Grovum 20 deprived their sheep of water during the infusion periods, thereby exacerbating the effects of the salts. It is deduced that the osmolality of rumen contents might be one factor influencing feed intake, but is not of over-riding importance.…”

Section: Metabolic Factorsmentioning

confidence: 99%

A personal view of how ruminant animals control their intake and choice of food: minimal total discomfort

Forbes

2007

Nutr. Res. Rev.

View full text Add to dashboard Cite

Voluntary food intake and the selection between foods are important subjects especially in ruminants in view of the economic importance of this class of animal and the complex digestive system with its attendant metabolic peculiarities. There is evidence that intake is limited by the capacity of the rumen as well as by metabolic factors; some theories assume that intake is controlled by the first limiting factor but this is not satisfying on physiological grounds and there is evidence that signals from feedback factors are integrated in an additive manner. It is now well established from research in which animals are given the chance to learn the metabolic consequences of eating food with a particular sensory profile, including a choice of foods, that animals including ruminants can adjust their diet, both quantitatively and qualitatively, to their nutrient requirements. It is proposed that they do this in order to minimise the total of the discomfort generated by the several signals from various body systems. The learning process is aided by the considerable day-to-day variation often seen in the intake of individual animals. An optimisation model is proposed and presented in a simple form, involving the addition of discomforts (calculated as the square of the deviation of the supply of metabolisable energy, crude protein and neutral-detergent fibre) and iterative elucidation of the intake at which total discomfort is minimal. With parameters appropriate for growing lambs the model provides reasonable agreement with observations, both in terms of daily intake and selection between foods of different protein contents. Manipulation of food composition and of nutrient requirements produces predictions broadly in agreement with reality except that protein deficiency has less severe consequences for the model than for real animals; it is proposed that protein deficiency be given more weighting than protein excess, and this may be true for other resources as well. This model is proposed as a philosophy and a starting point for further development and is not purveyed as a complete, working model. It nevertheless provides support for the concept of total minimal discomfort as a suitable base from which to view the control of intake and selection in all animals.Voluntary food intake: Diet selection: Models: Ruminants: Minimal total discomfort

show abstract

“…For a given level of energy infused, feed intake response is inversely proportional to the size of the molecule. Osmolarity in the rumen, however, seems to be a major satiation factor, as salt infusion studies have shown (Ternouth & Beattie, 1971;Bergen, 1972). This observation suggests that the VFA action cue may be of an osmotic nature.…”

Section: Energy Nutrientsmentioning

confidence: 99%

The effect of nutrients on feed intake in ruminants

Faverdin

1999

Proc. Nutr. Soc.

View full text Add to dashboard Cite

The purpose of the present review is to examine the role played by nutrients in controlling feed intake in ruminants, in light of their particular anatomical, physiological, nutritional and behavioural characteristics. The ration is first digested in the rumen for several hours by microbial fermentation. Volatile fatty acids, which constitute 50-75 % of a ruminant's energy supply, considerably depress feed intake when administered by short-term infusion into the rumen. However, this effect seems to be largely due to osmolarity problems. Only propionate seems to have a specific action, unrelated to osmolarity, in the mesenteric or portal veins. Nitrogenous nutrients have little short-term effect on feed intake, except when there is excess NH 3 in the rumen. Metabolic cues from intestinal digestion, particularly of glucose and starch, have very little shortor long-term influence in controlling feed intake, in comparison with rumen digestion cues. However, the short-term responses in feeding behaviour do not always reflect longer-term effects on feed intake control. The effects of volatile fatty acid infusion on feed intake are much less significant over the long term, except in the case of propionate. The nutrients required for good microbial activity (proteins in the rumen) generally promote feed intake, whereas nutrients that disrupt rumen functioning (lipids) reduce feed intake. After a learning period, preferences are always governed by a tendency toward optimum rumen functioning, rather than by animal nutritional requirements, although the two factors are not independent. Ruminants, due to their particular anatomical and nutritional characteristics, have, in the course of their evolution, developed specific feed intake control mechanisms based on nutritional cues. RésuméL'objet de cette revue est d'étudier le rôle des nutriments dans les mécanismes de contrôle de la prise alimentaire chez les ruminants, en tenant compte de leurs particularités anatomiques, physiologiques, nutritionnelles et comportementales. La digestion de la ration se déroule d'abord pendant de nombreuses heures dans le rumen par fermentation des aliments par des microbes. Les acides gras volatils, qui constituent 50-75 % des nutriments énergétiques d'un ruminant, présentent des effets rassasiants marqués lorsqu'ils sont perfusés dans le rumen. Cependant, ces effets semblent liés dans une large mesure à des problèmes d'osmolarité. Seul le propionate semble agir avec une action spécifique autre que l'osmolarité au niveau des veines mésentériques ou porte. Les nutriments azotés ont peu d'effet à court terme sur la prise alimentaire, excepté en cas d'excès d'ammoniac du rumen. Les signaux métaboliques provenant de l'absorption intestinale, en particulier le glucose ou l'amidon, ont très peu d'effet, à court ou long terme, dans le contrôle de la prise d'aliment comparativement aux signaux provenant de la digestion ruminale. Mais les réponses observées à court terme dans le contrôle de la prise alimentaire ne présagent pas toujours des effets à ...

show abstract

Studies of the food intake of sheep at a single meal

Cited by 43 publications

References 18 publications

Changes during eating in oxygen consumption, cardiac function and body fluids of sheep

Changes during eating in oxygen consumption, cardiac function and body fluids of sheep

A personal view of how ruminant animals control their intake and choice of food: minimal total discomfort

The effect of nutrients on feed intake in ruminants

Contact Info

Product

Resources

About