Summit metabolism in newborn lambs

Eales, FA; Small, J.

doi:10.1016/s0034-5288(18)32666-3

Cited by 34 publications

(6 citation statements)

References 20 publications

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“…Basal metabolism of neonates is affected by a number of factors that may confound experimental results, the most evident of these being ambient temperature. Ratio of summit metabolism, a measure of maximum rate of heat production in response to cold temperatures, to basal metabolism was 4.6:1 in newborn iambs (Eales and Small, 1980) and 3.6:1 in newborn calves (Young et al, 1986). Other factors known to affect basal metabolism in neonates include: 1) colostrum intake (LeDividich and Noblet, 1984;Eales and Small, 1981), 2) age (Thompson and Clough, 1970;Vermorel et al, 1983), 3) physical activity (Vermorel et al, 1983), 4) hypoxic conditions due to dystocia (Vermorel et al, 1983;Eales and Small, 1985) and 5) weight (Alexander, 1962a;Young et al, 1986).…”

Section: Resultsmentioning

confidence: 99%

Effects of Prepartum Protein Nutrition and Birth Weight on Basal Metabolism in Bovine Neonates

Carstens

Johnson

Holland

et al. 1987

Journal of Animal Science

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Recipient beef heifers, pregnant with single demi-embryos, were paired according to identical twin or full-sib embryo. Within pair, recipient heifers were assigned to one of two isocaloric diets containing a control or restricted level of protein (91 vs 55% of National Research Council recommendations) on d 190 of gestation. Following parturition, calves were weighed, fed 1 liter of colostrum, dried and placed in a metabolic chamber at 5 h of age for an 8-h determination of heat production (HP). Maternal body weight gains (P<.001) during the last trimester and body condition scores at parturition (P<.05) were reduced in heifers fed the protein-restricted diet. Calves born to heifers fed the protein-restricted diet had 11.4% lower (P<.O5) HP than calves born to control heifers (43.7 vs 49.3 kcal'kg-1 "d-~). Birth weights, respiratory quotients and rectal temperatures of newborn calves were not significantly affected by prepartum protein restriction. Within treatment groups, the relationship between HP and weight was described by the equation: HP (kcal/d) = 2.30 wt TM. The allometric exponent of 1.86-+ .26 implied that weight-specific metabolic rate was higher rather than lower in larger weight calves. We concluded that the thermogenie ability of neonatal calves may be compromised by prepartum protein restriction and(or) small birth weights.

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Section: Resultsmentioning

confidence: 99%

Effects of Prepartum Protein Nutrition and Birth Weight on Basal Metabolism in Bovine Neonates

Carstens

Johnson

Holland

et al. 1987

Journal of Animal Science

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“…Further details of the apparatus have been given by Slee, Griffiths and Samson (1980), Samson and Slee (1981) and Samson (1982). The procedure was as described by Eales and Small (1980). From an initial thermoneutral temperature of 38-5°C the water was cooled by 0-5°C/min until rectal temperature reverted, after the typical initial increase, to its minimum value at thermoneutrality.…”

Section: Methodsmentioning

confidence: 99%

The effect of environmental temperature during pregnancy on thermoregulation in the newborn lamb

Stott

Slee

1985

Anim. Sci.

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Twenty-four pregnant Scottish Blackface ewes were divided into three temperature-treatment groups 14 days before expected lambing: closely shorn and kept at 6°C (cold treatment, CD); in full fleece at 26°C (warm treatment, WM); and in full fleece at 6°C (controls, CL). Food allocation and intakes were similar for each group. Their lambs were tested for cold-induced summit metabolic rate capability (SMR) on the day of birth at a mean age of 12 h using water immersion to provide cooling. On the following day, the calorigenic response to subcutaneous injections of noradrenaline (NA) was measured to assess non-shivering thermogenesis capability. The ewes were blood-sampled during pregnancy and the lambs before and after the SMR test.In the ewes, .blood glucose and free fatty acid levels were higher during cold treatment, but not significantly so. Blood glucose was lower in lambs from CD ewes (CD lambs) before SMR tests; other differences were not significant.During the cold test, SMR was highest in CD lambs, but not significantly so. Rectal temperature declined least during test in the CD lambs (P < 0-05).The peak metabolic response (PMR) following NA injection was about 1-5 times greater in CD lambs than in the CL and WM lambs (P < 0-05). The mean elevation of PMR over thermoneutral metabolic rate was respectively: 2-8, 1-8 and 1-7 times in the CD, CL and WM lambs (P < 0-05), and this elevation was sustained for longer in the CD lambs (P < 0-01). Thus, the total metabolic response to NA was markedly greater in CD lambs.It was concluded that cold exposure during late pregnancy favoured the deposition of (or checked the normal decline in) foetal brown adipose tissue, so raising the neonatal capacity for non-shivering thermogenesis.

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“…Heat produced by the fetus is lost down that temperature gradient and is dissipated by the mother’s overriding thermoregulatory capability. Notwithstanding this exposure to a narrow range of temperatures in utero, cutaneous thermoreceptors demonstrably develop the capability to elicit metabolic responses to cold challenge, both shortly before birth when fetal lambs are experimentally cooled in utero [102,103,104,105] and immediately after birth when newborns are exposed to ambient cold (e.g., lambs [106]; lambs, piglets, and human infants [12]; lambs, kids, calves, foals, and piglets [107]).…”

Section: The Intrauterine Sensory Environment Of the Embryo/fetusmentioning

confidence: 99%

Preparing for Life After Birth: Introducing the Concepts of Intrauterine and Extrauterine Sensory Entrainment in Mammalian Young

Mellor

2019

Animals

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Simple SummaryA key event in the life of a mammalian fetus is its birth, especially in view of the exceptional change in its environment that occurs at birth. An area of great interest is the extent to which factors within the uterus prepare the fetus for birth and postnatal life. These and other factors are evaluated here for mammalian young that exhibit mature, moderately immature, and exceptionally immature neurological development at birth. A striking finding is the basic uniformity of various preparatory processes despite the diversity of birth-related circumstances among different terrestrial mammals. Numerous scientific disciplines have contributed to understanding in this area. Accordingly, the major purpose of this review is to construct from these diverse sources an integrated account of important facets of our current understanding. The primary focus is on how a progressive improvement in the functional effectiveness of the sensory systems for touch, temperature, taste, smell, balance/movement, hearing, and sight equips young mammals to cope successfully with the considerable challenge of being expelled from the uterus into the outside world. It is shown that the sensory environment in the uterus interacts with the genetically preprogrammed development of the apparatus for each sensory modality. It is also shown that the way this occurs can embed stimulus-response capabilities that can be accessed and beneficially utilised after birth. This phenomenon is called “trans-natal sensory continuity”. This embedding of sensory capabilities has previously been described as “learning” and the subsequent accessing of these embedded capabilities as “memory”. However, it is noted that such “learning” and “memory” processes are sometimes mistakenly thought to require the fetus to be conscious, a view which does not accord with established understanding of learning processes, nor with compelling contrary evidence from direct studies of fetal brain states. The solution proposed is to describe trans-natal sensory continuity in terms of the neurophysiological mechanisms involved and not as learning and memory outcomes. Introduced here, therefore, is the concept of “intrauterine sensory entrainment”. Its specific mechanistic basis is the well-established way nervous systems respond to sensory stimuli by reorganising their neural structures, functions, and connections. Known as neuroplasticity, this is recognised as integral to both prenatal and postnatal brain development and as the basis of postnatal learning and memory. Thus, intrauterine sensory entrainment is the mechanism by which trans-natal sensory continuity is achieved. It begins with the prenatal embedding of responsiveness to particular sensory inputs which are generated by the stimulation of specific receptors once the neurological apparatus for that sensory modality has begun to develop. Thereafter, this process continues until birth, and this makes all such entrained sensory capabilities available to operate after birth. Nevertheless, all sensory systems th...

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Summit metabolism in newborn lambs

Cited by 34 publications

References 20 publications

Effects of Prepartum Protein Nutrition and Birth Weight on Basal Metabolism in Bovine Neonates

Effects of Prepartum Protein Nutrition and Birth Weight on Basal Metabolism in Bovine Neonates

The effect of environmental temperature during pregnancy on thermoregulation in the newborn lamb

Preparing for Life After Birth: Introducing the Concepts of Intrauterine and Extrauterine Sensory Entrainment in Mammalian Young

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