Digestion and metabolism of carbohydrates in the foetal and neonatal ruminant

Leat, W. M. F.

doi:10.1079/pns19710046

Cited by 7 publications

(1 citation statement)

References 37 publications

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“…Concentrations of G in blood samples taken after feed was withheld overnight were in the normal range for veal calves. In calves raised for beef or breeding (i.e., not solely milk fed) and in lambs in the unfed state (Jarrett et al, 1964;Leat, 1971;Fahey and Berger, 1988), unfed G concentrations decrease with age. Because G concentrations when feed was with- held in our trial remained stable, development of hyperglycemia relative to beef calves was detected.…”

Section: Insulin and Glucose In The Unfed Statementioning

confidence: 99%

Insulin resistance, hyperglycemia, and glucosuria in intensively milk-fed calves

Hostettler-Allen¹,

Tappy

Blum³

1994

Journal of Animal Science

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In intensively milk-fed calves post-prandial glucose (G) and insulin (I) concentrations, but not preprandial G concentrations, increased or failed to decrease during the growth period, compared with data from calves that were progressively weaned. This study was, therefore, designed to investigate G and I metabolism in veal calves. Euglycemic-hyperinsulinemic and hyperglycemic clamps in the unfed state demonstrated mutual responsiveness of I and G, but revealed a relative I resistance. After feed consumption, I resistance was exaggerated, as seen by decreased G clearance rates after i.v. G and I administration in fed compared with unfed calves. Milk replacer is a source of readily available lactose, fat, and protein, the intake of which, on a kilogram.75 basis, gradually increased with age. Increased substrate availability and effects of nutrients themselves were probably responsible for elevated plasma concentrations of G and I and led to I resistance. Additionally, hyperglycemia > 1.5 g/L was followed by urinary excretion of G.

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Section: Insulin and Glucose In The Unfed Statementioning

confidence: 99%

Insulin resistance, hyperglycemia, and glucosuria in intensively milk-fed calves

Hostettler-Allen¹,

Tappy

Blum³

1994

Journal of Animal Science

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Calcitonin in the mother, fetus and newborn

Garel¹,

Barlet²

1978

Ann. Biol. anim. Bioch. Biophys.

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Summary. The high plasma calcitonin level in the mother during gestation and lactation protected the maternal skeleton against excessive demineralization. The relative independence of fetal calcemia from the maternal plasma calcium concentration was well established and the concept of hormonal autonomy of fetal secretion of parathyroid hormone and calcitonin developed. However, the role of these hormones during fetal life remained obscure. A new aspect of calcitonin physiology in the newborn, the regulation of nutrient absorption through gastric emptying, is mentioned.The mother.Calcium needs are increased in the female during gestation and lactation. Comar (1956) has shown that the transfer of calcium through the placenta and the mammary gland is greatest at the end of gestation and during lactation, respectively.Kinetic studies using calcium 45 demonstrated that fetal and newborn calcium contents were originated from maternal intestinal absorption and/or maternal skeleton, the relative importance of the two contributions being species-dependent. According to Wasserman et al. (1957), 92 p. 100 of the fetal calcium in rat is of maternal dietary origin. In contrast, intestinal calcium absorption in ruminants is not sufficient to cover th e calcium needs of the fetus or of the newborn in lactating cows (Symonds et al., 1966) and in pregnant ewes (Braithwaite, Glascock and Riazuddin, 1969 ;Braithwaite, Glascock and Riazuddin, 1970), the calcium being supplied by maternal bone resorption.In many species, the intestinal absorption increases. Chef (1969) (Garel, 1970a ;Pic, Maniey and Jost, 1965 ;Pic, 1973) which is corrected by parathyroid extract injection (Garel, Pic and Jost, 1971) (table 1). Thyroparathyroidectomy in rat fetus delayed recovery from EDTA-induced hypocalcemia (Garel, 1975). Higher calcemia in the fetus than in the mother in thyroparathyroidectomized rat fetus from thyroparathyroidectomized mother (Pic, 1968) (Garel, Milhaud and Jost, 1968). A larger dose (140 MRC mU/g body weight of salmon CT) must be given to decrease the fetal plasma magnesium level . In preliminary experiments, Littledike, Arnaud and Whipp (1972) have shown that CT injected intravenously into fetal piglet had no effect on plasma calcium levels in contrast to newborn piglet. In Rhesus monkey fetus, CT induced a triphasic effect with time on the plasma calcium level : a rapid decline, followed by recovery, and then a sluggish decrease (Reynolds, Pitkin and Wezeman, 1975 The Newborn.The placental outflow of calcium disappears at birth and the plasma calcium level decreases sharply in newborn rat (Garel, 1969). The hypocalcemic and hypophosphatemic effects of CT were more intense in the newborn rat than in rat fetus (Garel, 1969 ; Garel and Barlet,1974) ; the newborns were also more sensitive to the hormone since subcutaneous injection of a lower dose (1:5) markedly decreased plasma calcium and inorganic phosphorus concentrations . The injection of a large dose of CT in the suckling newborn rat had a clearing effect on plasma ...

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Changes in the pattern of glucose metabolism in growth, pregnancy and lactation in ruminants

Lindsay

1971

Proc. Nutr. Soc.

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The carbohydrate needs of pregnancy and lactation are of particular interest in ruminants because of their dependence on gluconeogenesis. The rate of gluconeogenesis (glucose entry rate) can therefore be determined by isotope dilution in fed or fasted ruminants. In sheep starved for 6 d the rate is about 120-140 mg/h per kg0.75, which compares closely to values in fasted non-ruminants (Cowan, Vranic & Wrenshall, 1969;Owen, Felig, Morgan, Wahren & Cahill, 1969). The increased rate in fed ruminants may be related to either digestible energy (DE) or to protein intake (Judson & Leng, 1968), but over a wider range of rations and animals there is a much better relationship with DE than with protein intake (Lindsay, 1970). This is probably because the DE intake determines the rate of volatile fatty acid production and thus, also, the rate of synthesis of microbial protein, which probably accounts for most of the protein available to ruminants . It is assumed that the major precursors of glucose are propionate and glycogenic amino acids.In pregnant sheep, Steel & Leng (1968) showed that the glucose entry rate is determined more by the food intake than by the stage of pregnancy. It is possible that on a fixed ration there is a slight increase in the glucose entry rate as pregnancy develops, but such increase is small compared with the effect of increased feed intake. When ewes were offered lucerne ad lib. they increased their intake markedly in late pregnancy; glucose entry rate was increased but not as much as might be https://www.cambridge.org/core/terms. https://doi

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Digestion and metabolism of carbohydrates in the foetal and neonatal ruminant

Cited by 7 publications

References 37 publications

Insulin resistance, hyperglycemia, and glucosuria in intensively milk-fed calves

Insulin resistance, hyperglycemia, and glucosuria in intensively milk-fed calves

Calcitonin in the mother, fetus and newborn

Changes in the pattern of glucose metabolism in growth, pregnancy and lactation in ruminants

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