The effect of late pregnancy on the diet selections made by ewes

Cooper, S. D. B.; Kyriazakis, Ι.; Oldham, J. D.

doi:10.1016/0301-6226(94)90094-9

Cited by 39 publications

(28 citation statements)

References 17 publications

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“…The results of a series of subsequent experiments were consistent with the idea that cows, given a choice between foods with different RDP contents, selected sufficient RDP and also avoided eating an excess (Tolkamp et al 1998b). These findings need to be reconciled with the results of other research in which ruminants seemed to be able to select a diet that reflected their protein needs according to their physiological state (Kyriazakis & Oldham, 1993;Cooper et al 1994;Kyriazakis et al 1994). In the latter experiments there were differences between the diets used in both their calculated MP yields and in their RDP contents, and it is not clear whether the diet selection observed in these experiments should be interpreted in terms of the MP or the RDP axis.…”

Section: The Role Of Internal State In Diet Selectionsupporting

confidence: 64%

Diet selection and animal state: an integrative framework

1999

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In the present paper we deal with the problems of explaining and predicting diet selection of animals under controlled conditions, i.e. conditions that can be described and in which any influences of the environment can be either controlled or at least monitored. Diet selection is considered within an integrative framework of feeding behaviour that views both food intake and diet selection as an outcome of the animal's internal state and knowledge of the feeding environment. Three questions that arise from the framework are considered: (1) how do animals learn about foods available to them as a choice? (2) what changes in internal state affect diet selection? (3) how much time is needed for a change in the animal's internal state to be detected and for it to react to this change through a modification of its diet selection? It is proposed that animals have developed behavioural mechanisms that allow them to recognize foods on the basis of their nutritional as well as other properties. The rate at which animals learn about foods depends largely on the extent of the animal's deficiency and on the extent of the post-ingestive consequences induced by the foods. There is little evidence that animals modify their diet selection in response to short-term systemic fluctuation of their internal environment. On the other hand, long-term changes in the internal state of the animal lead to consequent long-term changes in diet selection. The time needed for a change in diet selection to be observed depends on the deviation created in the animal's internal state, either as a result of a physiological change or as a consequence of feeding. Thus, a more appropriate question to consider is not 'what time period matters to the animal?' but 'how much change or deviation in the internal state is the animal prepared to accept?'

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Section: The Role Of Internal State In Diet Selectionsupporting

confidence: 64%

Diet selection and animal state: an integrative framework

1999

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“…In accordance with this proposal, food intake is frequently observed to decline over a number of days prior to parturition in several species including mice (e.g. Cooper et al, 1994;French, 2006;Gordon and Tribe, 1951;Johnson et al, 2001a). This tradeoff may potentially impose a limit on total reproductive investment, and more generally competition by different organs for abdominal space has been envisaged as a constraining factor in evolution, particularly in herbivores (Clauss et al, 2003).…”

Section: Introductionmentioning

confidence: 78%

Limits to sustained energy intake. XVI. Body temperature and physical activity of female mice during pregnancy

Gamo

Bernard

Mitchell

et al. 2013

Journal of Experimental Biology

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SUMMARYLactation is the most energy-demanding phase of mammalian reproduction, and lactation performance may be affected by events during pregnancy. For example, food intake may be limited in late pregnancy by competition for space in the abdomen between the alimentary tract and fetuses. Hence, females may need to compensate their energy budgets during pregnancy by reducing activity and lowering body temperature. We explored the relationships between energy intake, body mass, body temperature and physical activity throughout pregnancy in the MF1 mouse. Food intake and body mass of 26 females were recorded daily throughout pregnancy. Body temperature and physical activity were monitored every minute for 23h a day by implanted transmitters. Body temperature and physical activity declined as pregnancy advanced, while energy intake and body mass increased. Compared with a pre-mating baseline period, mice increased energy intake by 56% in late pregnancy. Although body temperature declined as pregnancy progressed, this served mostly to reverse an increase between baseline and early pregnancy. Reduced physical activity may compensate the energy budget of pregnant mice but body temperature changes do not. Over the last 3days of pregnancy, food intake declined. Individual variation in energy intake in the last phase of pregnancy was positively related to litter size at birth. As there was no association between the increase in body mass and the decline in intake, we suggest the decline was not caused by competition for abdominal space. These data suggest overall reproductive performance is probably not constrained by events during pregnancy. Supplementary material available online at

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“…They seem able to discriminate the effects of energy and protein (Wang and Provenza, 1996a), and faced with a choice between foods varying in both, sheep select diets with relatively constant protein/energy ratios (Kyriazakis and Oldham, 1993;Provenza et al, 1996). Previous work has shown that sheep balance their intake of ruminally degradable proteins and soluble carbohydrates (Kyriazakis and Oldham, 1997), according to their requirements (Cooper et al, 1994). Furthermore, their voluntary intake of roughages also appears to be related to the protein/energy ratios of digestion products that arise from roughage consumption (Egan, 1977).…”

Section: Introductionmentioning

confidence: 99%

“…In the current work, we investigated a more complex feeding situation by applying the conditioning method in a choice situation involving three foods, each associated with both energy-based and protein-based postingestive consequences of varying intensity. Furthermore, since modification of nutritional state leads to a change in nutrient requirements and diet selection (Cooper et al, 1994;Kyriazakis et al, 1994;Wang and Provenza, 1996b;Villalba and Provenza, 1999b), we tested preferences of animals fed a basal diet allowing different growth rates on an energy and protein basis in order to see whether the low nutritional level would make them more sensitive to nutrient rewards.…”

Section: Introductionmentioning

confidence: 99%

Diet learning through post-ingestive consequences in sheep: the case of starch and casein variously combined in the same foods

Ginane

Baumont

Duncan³

2009

Animal

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Ruminants generally succeed in selecting an appropriate diet relative to their nutrient requirements, and macronutrients such as energy and protein are considered as playing a primary role in their food preferences. Diet learning through post-ingestive consequences, evidenced by many studies that involved situations with simple discrimination tasks, may explain this ability to select a suitable diet. However, in more complex feeding environments where animals are faced with many plants varying both in their energy and protein contents, the extent to which such a mechanism operates is still uncertain. Our objective was to investigate a more complex feeding situation than previously tested and to determine whether lambs were able to associate three forages with both energy-based and protein-based post-ingestive consequences of various intensities. The doses of starch and casein used to elicit these post-ingestive consequences were chosen so that the apparent metabolisable energy and crude protein values of hays were within the range found in plants normally encountered under field conditions. We applied five treatments: EmPm, EhPm, EmPh, EhPh, where medium (m) or high (h) levels of nutrients (E 5 energy and P 5 protein) were associated with different hays, and E0N0 where no stimuli were associated. Each animal experienced only three treatments: E0N0-EmPm-EhPm or E0N0-EmPh-EhPh, each one being associated with one hay during conditioning, on the basis of one treatment per day over three consecutive days. Animals then had a choice between the hay associated with E0N0 and one of the two others, successively on the two following days. This procedure was repeated through five 1-week-long periods, and applied to two groups of lambs (n 5 12) maintained at feeding levels sufficient for maintenance or for a 150 g/day growth rate. This experiment was complemented by a methodological trial that aimed to estimate the doses of starch and casein eliciting preferences and a post-trial that aimed to evaluate the effect of our treatments on sheep ruminal environment. The methodological trial showed that lambs perceived the stimuli and the doses, and the post-trial showed that treatments affected the ruminal environment. In the main experiment, the lambs preferred the rewarded hays but did not discriminate in their choices the variation of post-ingestive consequences due to energy and protein. This suggests that in situations closer to reality where animals experience many foods varying in nutrient contents, the learning process may be impaired. The lambs do not seem to have strictly relied on it for shaping their diet choices.

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The effect of late pregnancy on the diet selections made by ewes

Cited by 39 publications

References 17 publications

Diet selection and animal state: an integrative framework

Diet selection and animal state: an integrative framework

Limits to sustained energy intake. XVI. Body temperature and physical activity of female mice during pregnancy

Diet learning through post-ingestive consequences in sheep: the case of starch and casein variously combined in the same foods

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