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Nicolas Charles Friggens - One of the best experts on this subject based on the ideXlab platform.
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evaluating the ability of a lifetime Nutrient Partitioning model for simulating the performance of australian holstein dairy cows
Animal Production Science, 2017Co-Authors: Huynh Nguyen Bao Phuong, Nicolas Charles Friggens, Olivier C Martin, Pierre Blavy, Ben J Hayes, W J Wales, J E PryceAbstract:The present study determined the ability of a lifetime Nutrient-Partitioning model to simulate individual genetic potentials of Australian Holstein cows. The model was initially developed in France and has been shown to be able to accurately simulate performance of individual cows from various breeds. Generally, it assumes that the curves of cow performance differ only in terms of scaling, but the dynamic shape is universal. In other words, simulations of genetic variability in performance between cow genotypes can be performed using scaling parameters to simply scale the performance curves up or down. Validation of the model used performance data from 63 lactations of Australian Holstein cows offered lucerne cubes plus grain-based supplement. Individual cow records were used to derive genetic scaling parameters for each animal by calibrating the model to minimise root mean-square errors between observed and fitted values, cow by cow. The model was able to accurately fit the curves of bodyweight, milk fat concentration, milk protein concentration and milk lactose concentration with a high degree of accuracy (relative prediction errors <5%). Daily milk yield and weekly body condition score were satisfactorily predicted, although slight under-predictions of milk yield were identified during the last stage of lactation (relative prediction errors ≈11.1–15.6%). The prediction of feed intake was promising, with the value of relative prediction error of 18.1%. The results also suggest that the current recommendation of energy required for maintenance of pasture-based cows might be under-estimated. In conclusion, this model can be used to simulate genetic variability in the production potential of Australian cows. Thus, it can be used for simulation of consequences of future genetic-selection strategies on lifetime performance and efficiency of individual cows.
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Prediction of the lifetime productive and reproductive performance of Holstein cows managed for different lactation durations, using a model of lifetime Nutrient Partitioning
Journal of Dairy Science, 2016Co-Authors: C. Gaillard, Nicolas Charles Friggens, Olivier Martin, Pierre Blavy, J. Sehested, H.n. PhuongAbstract:The GARUNS model is a lifetime performance model taking into account the changing physiological priorities of an animal during its life and through repeated reproduction cycles. This dynamic and stochastic model has been previously used to predict the productive and reproductive performance of various genotypes of cows across feeding systems. In the present paper, we used this model to predict the lifetime productive and reproductive performance of Holstein cows for different lactation durations, with the aim of determining the lifetime scenario that optimizes cows’ performance defined by lifetime efficiency (ratio of total milk energy yield to total energy intake) and pregnancy rate. To evaluate the model, data from a 16-mo extended lactation experiment on Holstein cows were used. Generally, the model could consistently fit body weight, milk yield, and milk components of these cows, whereas the reproductive performance was overestimated. Cows managed for repeated 12-, 14-, or 16-mo lactation all their life were simulated and had the highest lifetime efficiency compared with shorter (repeated 10-mo lactations: scenario N-N) or longer lactations (repeated 18-, 20-, or 22-mo lactations). The pregnancy rates increased slightly from a 10-mo to a 16-mo lactation but not significantly. Cows managed for a 16-mo lactation during their first lactation, followed by 10-mo lactations for the rest of their lives (EL-N scenario), had a similar lifetime efficiency as cows managed for 16-mo lactation all of their lives (EL-EL scenario). Cows managed for a 10-mo lactation during their first lactation, followed by 16-mo lactations for the rest of their lives (N-EL scenario), had a similar lifetime efficiency as that of the N-N scenario. The pregnancy rates of these 4 scenarios (N-N, EL-EL, N-EL, and EL-N) were similar to one another. To conclude, the GARUNS model was able to fit and simulate the extended lactation of Holstein cows. The simulated outputs indicate that managing the primiparous cows with a 16-mo extended lactation, followed by 10-mo lactations, allows their lifetime efficiency to increase and become similar to cows managed for 16-mo lactation during their entire lives. Further work should include health incidence (i.e., diseases) in the prediction model to have more accurate and realistic predictions of lifetime efficiency.
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deriving estimates of individual variability in genetic potentials of performance traits for 3 dairy breeds using a model of lifetime Nutrient Partitioning
Journal of Dairy Science, 2015Co-Authors: Huynh Nguyen Bao Phuong, Ph Schmidely, Klaus Lønne Ingvartsen, Nicolas Charles Friggens, Olivier Martin, Imke J.m. De BoerAbstract:This study explored the ability of an existing lifetime Nutrient Partitioning model for simulating individual variability in genetic potentials of dairy cows. Generally, the model assumes a universal trajectory of dynamic Partitioning of priority between life functions and genetic scaling parameters are then incorporated to simulate individual difference in performance. Data of 102 cows including 180 lactations of 3 breeds: Danish Red, Danish Holstein, and Jersey, which were completely independent from those used previously for model development, were used. Individual cow performance records through sequential lactations were used to derive genetic scaling parameters for each animal by calibrating the model to achieve best fit, cow by cow. The model was able to fit individual curves of body weight, and milk fat, milk protein, and milk lactose concentrations with a high degree of accuracy. Daily milk yield and dry matter intake were satisfactorily predicted in early and mid lactation, but underpredictions were found in late lactation. Breeds and parities did not significantly affect the prediction accuracy. The means of genetic scaling parameters between Danish Red and Danish Holstein were similar but significantly different from those of Jersey. The extent of correlations between the genetic scaling parameters was consistent with that reported in the literature. In conclusion, this model is of value as a tool to derive estimates of genetic potentials of milk yield, milk composition, body reserve usage, and growth for different genotypes of cow. Moreover, it can be used to separate genetic variability in performance between individual cows from environmental noise. The model enables simulation of the effects of a genetic selection strategy on lifetime efficiency of individual cows, which has a main advantage of including the rearing costs, and thus, can be used to explore the impact of future selection on animal performance and efficiency.
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Advances in predicting Nutrient Partitioning in the dairy cow: recognizing the central role of genotype and its expression through time
animal, 2013Co-Authors: Nicolas Charles Friggens, Laure Brun-lafleur, Philippe Faverdin, Daniel Sauvant, Olivier MartinAbstract:In recent years, it has become increasingly clear that understanding Nutrient Partitioning is central to a much broader range of issues than just being able to predict productive outputs. The extent to which Nutrients are partitioned to other functions such as health and reproduction is clearly important, as are the efficiency consequences of Nutrient Partitioning. Further, with increasing environmental variability, there is a greater need to be able to predict the ability of an animal to respond to the nutritional limitations that arise from the environment in which it is placed. How the animal partitions its Nutrients when resources are limited, or imbalanced, is a major component of its ability to cope, that is, its robustness. There is mounting evidence that reliance on body reserves is increased and that robustness of dairy cows is reduced by selection for increased milk production. A key element for predicting the partition of Nutrients in this wider context is to incorporate the priorities of the animal, that is, an explicit recognition of the role of both the cow's genotype (genetic make-up), and the expression of this genotype through time on Nutrient Partitioning. Accordingly, there has been a growing recognition of the need to incorporate in nutritional models these innate driving forces that alter Nutrient Partitioning according to physiological state, the genetically driven trajectories. This paper summarizes some of the work carried out to extend nutritional models to incorporate these trajectories, the genetic effects on them, as well as how these factors affect the homeostatic capacity of the animal. At present, there are models capable of predicting the partition of Nutrients throughout lactation for cows of differing milk production potentials. Information concerning genotype and stage of lactation effects on homeostatic capacity has not yet been explicitly included in metabolic models that predict Nutrient partition, although recent results suggest that this is achievable. These developments have greatly extended the generality of Nutrient Partitioning models with respect to the type of animal and its physiological state. However, these models remain very largely focussed on predicting partition between productive outputs and body reserves and, for the most part, remain research models, although substantial progress has been made towards developing models that can be applied in the field. The challenge of linking prediction of Nutrient Partitioning to its consequences on health, reproduction and longevity, although widely recognized, is only now beginning to be addressed. This is an important perspective for future work on Nutrient Partitioning.
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towards a biological basis for predicting Nutrient Partitioning the dairy cow as an example
Animal, 2007Co-Authors: Nicolas Charles Friggens, J R NewboldAbstract:Prediction of Nutrient Partitioning is a long-standing problem of animal nutrition that has still not been solved. Another substantial problem for nutritional science is how to incorporate genetic differences into nutritional models. These two problems are linked as their biological basis lies in the relative priorities of different life functions (growth, reproduction, health, etc.) and how they change both through time and in response to genetic selection. This paper presents recent developments in describing this biological basis and evidence in support of the concepts involved as they relate to Nutrient Partitioning. There is ample evidence that at different stages of the reproductive cycle various metabolic pathways, such as lipolysis and lipogenesis, are up or down regulated. The net result of such changes is that Nutrients are channelled to differing extents to different organs, life functions and end-products. This occurs not as a homeostatic function of changing nutritional environment but rather as a homeorhetic function caused by the changing expression of genes for processes such as milk production through time. In other words, the animal has genetic drives and there is an aspect of Nutrient Partitioning that is genetically driven. Evidence for genetic drives other than milk production is available and is discussed. Genetic drives for other life functions than just milk imply that Nutrient Partitioning will change through lactation and according to genotype – i.e. it cannot be predicted from feed properties alone. Progress in describing genetic drives and homeorhetic controls is reviewed. There is currently a lack of good genetic measures of physiological parameters. The unprecedented level of detail and amounts of data generated by the advent of microarray biotechnology and the fields of genomics, proteomics, etc. should in the long-term provide the necessary information to make the link between genetic drives and metabolism. However, gene expression, protein synthesis etc, have all been shown to be environmentally sensitive. Thus, a major challenge in realising the potential afforded by this new technology is to be able to be able to distinguish genetically driven and environmentally driven effects on expression. To do this we need a better understanding of the basis for the interactions between genotypes and environments. The biological limitations of traditional evaluation of genotype £ environment interactions and plasticity are discussed and the benefits of considering these in terms of trade-offs between life functions is put forward. Trade-offs place Partitioning explicitly at the centre of the resource allocation problem and allow consideration of the effects of management and selection on multiple traits and on Nutrient Partitioning.
Amanda N Sferruzziperri - One of the best experts on this subject based on the ideXlab platform.
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an obesogenic diet during mouse pregnancy modifies maternal Nutrient Partitioning and the fetal growth trajectory
The FASEB Journal, 2013Co-Authors: Amanda N Sferruzziperri, O R Vaughan, Maria Isabel Grijalva Haro, Wendy N Cooper, Barbara Musial, Shruti Ayyar, Diogo Pestana, Anne C Fergusonsmith, Marika Charalambous, Graham J BurtonAbstract:In developed societies, high-sugar and high-fat (HSHF) diets are now the norm and are increasing the rates of maternal obesity during pregnancy. In pregnant rodents, these diets lead to cardiovascular and metabolic dysfunction in their adult offspring, but the intrauterine mechanisms involved remain unknown. This study shows that, relative to standard chow, HSHF feeding throughout mouse pregnancy increases maternal adiposity (+30%, P<0.05) and reduces fetoplacental growth at d 16 (−10%, P<0.001). At d 19, however, HSHF diet group pup weight had normalized, despite the HSHF diet group placenta remaining small and morphologically compromised. This altered fetal growth trajectory was associated with enhanced placental glucose and amino acid transfer (+35%, P<0.001) and expression of their transporters (+40%, P<0.024). HSHF feeding also up-regulated placental expression of fatty acid transporter protein, metabolic signaling pathways (phosphoinositol 3-kinase and mitogen-activated protein kinase), and several ...
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an obesogenic diet during mouse pregnancy modifies maternal Nutrient Partitioning and the fetal growth trajectory
The FASEB Journal, 2013Co-Authors: Amanda N Sferruzziperri, O R Vaughan, Maria Isabel Grijalva Haro, Wendy N Cooper, Barbara Musial, Shruti Ayyar, Diogo Pestana, Anne C Fergusonsmith, Marika Charalambous, Graham J BurtonAbstract:In developed societies, high-sugar and high-fat (HSHF) diets are now the norm and are increasing the rates of maternal obesity during pregnancy. In pregnant rodents, these diets lead to cardiovascular and metabolic dysfunction in their adult offspring, but the intrauterine mechanisms involved remain unknown. This study shows that, relative to standard chow, HSHF feeding throughout mouse pregnancy increases maternal adiposity (+30%, P<0.05) and reduces fetoplacental growth at d 16 (-10%, P<0.001). At d 19, however, HSHF diet group pup weight had normalized, despite the HSHF diet group placenta remaining small and morphologically compromised. This altered fetal growth trajectory was associated with enhanced placental glucose and amino acid transfer (+35%, P<0.001) and expression of their transporters (+40%, P<0.024). HSHF feeding also up-regulated placental expression of fatty acid transporter protein, metabolic signaling pathways (phosphoinositol 3-kinase and mitogen-activated protein kinase), and several growth regulatory imprinted genes (Igf2, Dlk1, Snrpn, Grb10, and H19) independently of changes in DNA methylation. Obesogenic diets during pregnancy, therefore, alter maternal Nutrient Partitioning, partly through changes in the placental phenotype, which helps to meet fetal Nutrient demands for growth near term. However, by altering provision of specific Nutrients, dietary-induced placental adaptations have important roles in programming development with health implications for the offspring in later life.
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early treatment of the pregnant guinea pig with igfs promotes placental transport and Nutrient Partitioning near term
American Journal of Physiology-endocrinology and Metabolism, 2007Co-Authors: Amanda N Sferruzziperri, Julie A Owens, Prue Standen, Robyn L Taylor, Gary K Heinemann, Jeffrey S Robinson, Claire T RobertsAbstract:Appropriate Partitioning of Nutrients between the mother and conceptus is a major determinant of pregnancy success, with placental transfer playing a key role. Insulin-like growth factors (IGFs) in...
Graham J Burton - One of the best experts on this subject based on the ideXlab platform.
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an obesogenic diet during mouse pregnancy modifies maternal Nutrient Partitioning and the fetal growth trajectory
The FASEB Journal, 2013Co-Authors: Amanda N Sferruzziperri, O R Vaughan, Maria Isabel Grijalva Haro, Wendy N Cooper, Barbara Musial, Shruti Ayyar, Diogo Pestana, Anne C Fergusonsmith, Marika Charalambous, Graham J BurtonAbstract:In developed societies, high-sugar and high-fat (HSHF) diets are now the norm and are increasing the rates of maternal obesity during pregnancy. In pregnant rodents, these diets lead to cardiovascular and metabolic dysfunction in their adult offspring, but the intrauterine mechanisms involved remain unknown. This study shows that, relative to standard chow, HSHF feeding throughout mouse pregnancy increases maternal adiposity (+30%, P<0.05) and reduces fetoplacental growth at d 16 (−10%, P<0.001). At d 19, however, HSHF diet group pup weight had normalized, despite the HSHF diet group placenta remaining small and morphologically compromised. This altered fetal growth trajectory was associated with enhanced placental glucose and amino acid transfer (+35%, P<0.001) and expression of their transporters (+40%, P<0.024). HSHF feeding also up-regulated placental expression of fatty acid transporter protein, metabolic signaling pathways (phosphoinositol 3-kinase and mitogen-activated protein kinase), and several ...
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an obesogenic diet during mouse pregnancy modifies maternal Nutrient Partitioning and the fetal growth trajectory
The FASEB Journal, 2013Co-Authors: Amanda N Sferruzziperri, O R Vaughan, Maria Isabel Grijalva Haro, Wendy N Cooper, Barbara Musial, Shruti Ayyar, Diogo Pestana, Anne C Fergusonsmith, Marika Charalambous, Graham J BurtonAbstract:In developed societies, high-sugar and high-fat (HSHF) diets are now the norm and are increasing the rates of maternal obesity during pregnancy. In pregnant rodents, these diets lead to cardiovascular and metabolic dysfunction in their adult offspring, but the intrauterine mechanisms involved remain unknown. This study shows that, relative to standard chow, HSHF feeding throughout mouse pregnancy increases maternal adiposity (+30%, P<0.05) and reduces fetoplacental growth at d 16 (-10%, P<0.001). At d 19, however, HSHF diet group pup weight had normalized, despite the HSHF diet group placenta remaining small and morphologically compromised. This altered fetal growth trajectory was associated with enhanced placental glucose and amino acid transfer (+35%, P<0.001) and expression of their transporters (+40%, P<0.024). HSHF feeding also up-regulated placental expression of fatty acid transporter protein, metabolic signaling pathways (phosphoinositol 3-kinase and mitogen-activated protein kinase), and several growth regulatory imprinted genes (Igf2, Dlk1, Snrpn, Grb10, and H19) independently of changes in DNA methylation. Obesogenic diets during pregnancy, therefore, alter maternal Nutrient Partitioning, partly through changes in the placental phenotype, which helps to meet fetal Nutrient demands for growth near term. However, by altering provision of specific Nutrients, dietary-induced placental adaptations have important roles in programming development with health implications for the offspring in later life.
Jacqueline Wallace - One of the best experts on this subject based on the ideXlab platform.
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the effect of overnourishing singleton bearing adult ewes on Nutrient Partitioning to the gravid uterus
British Journal of Nutrition, 2005Co-Authors: Jacqueline Wallace, John S Milne, R P AitkenAbstract:Overnourishing the singleton-bearing adolescent sheep throughout pregnancy promotes maternal tissue synthesis at the expense of the Nutrient requirements of the gravid uterus. Consequently, the growth of the placenta is impaired and results in the premature delivery of low-birth-weight lambs relative to moderately fed adolescents of equivalent age. To establish if this phenomenon is unique to the growing animal, singleton pregnancies to a single sire were established by embryo transfer into primiparous adult ewes who had attained the normal mature body size for their genotype. Thereafter ewes were offered a maintenance or a high level of a complete diet throughout gestation. High maternal intakes resulted in elevated maternal insulin, no significant change in growth hormone or glucose, and attenuated progesterone and NEFA concentrations. Live weight gain during the first 93 d of gestation was 48 and 244 g/d, and adiposity score at term was 2.4 and 3.7 in the maintenance and high groups, respectively (P<0.001). In spite of achieving levels of adiposity similar to overnourished adolescents, placental (477 (sem 30) v. 518 (sem 41) g) and fetal (5190 (sem 320) v. 5420 (sem 250) g) weights were equivalent in maintenance and high groups. Gestation length was shorter (P<0.01) and colostrum yield at parturition lower (P<0.05) in high v. maintenance dams. Thus, adult sheep appear to be relatively insensitive to the oversupply of Nutrients during pregnancy and have the ability to meet the Nutrient requirements for normal conceptus growth in spite of their increased adiposity.
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maternal growth hormone treatment from day 35 to 80 of gestation alters Nutrient Partitioning in favor of uteroplacental growth in the overnourished adolescent sheep
Biology of Reproduction, 2004Co-Authors: Jacqueline Wallace, John S Milne, R P AitkenAbstract:Abstract Overnourishing the pregnant adolescent ewe promotes maternal tissue synthesis at the expense of placental growth and leads to a major reduction in lamb birth weight at term. Growth hormone (GH) secretion is attenuated in these overnourished dams and the maternal somatotrophic axis may play a key role in coordinating Nutrient usage in the pregnant adolescent. Thus we investigated whether increasing maternal GH during the period of rapid placental proliferation alters Nutrient Partitioning between the maternal, placental, and fetal tissues as assessed at Day 81 of gestation. Adolescent recipient ewes were implanted with singleton embryos, derived from superovulated dams and a single sire on Day 4 postestrus. Thereafter, the ewes were offered either a high (H) or moderate intake (M) of the same complete diet. From Day 35 to 80 of gestation, ewes were either injected twice daily (s.c. at 0800 and 1800 h) with recombinant bovine GH (bGH, 0.14 mg/kg live weight/day) or remained untreated (n = 8 ewes pe...
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Nutrient Partitioning during adolescent pregnancy
Reproduction, 2001Co-Authors: Jacqueline Wallace, D A Bourke, P Da Silva, Raymond AitkenAbstract:Human adolescent mothers have an increased risk of delivering low birth weight and premature infants with high mortality rates within the first year of life. Studies using a highly controlled adolescent sheep paradigm demonstrate that, in young growing females, the hierarchy of Nutrient Partitioning during pregnancy is altered to promote growth of the maternal body at the expense of the gradually evolving Nutrient requirements of the gravid uterus and mammary gland. Thus, overnourishing adolescent dams throughout pregnancy results in a major restriction in placental mass, and leads to a significant decrease in birth weight relative to adolescent dams receiving a moderate Nutrient intake. High maternal intakes are also associated with increased rates of spontaneous abortion in late gestation and, for ewes delivering live young, with a reduction in the duration of gestation and in the quality and quantity of colostrum accumulated prenatally. As the adolescent dams are of equivalent age at the time of conception, these studies indicate that nutritional status during pregnancy rather than biological immaturity predisposes the rapidly growing adolescents to adverse pregnancy outcome. Nutrient Partitioning between the maternal body and gravid uterus is putatively orchestrated by a number of endocrine hormones and, in this review, the roles of both maternal and placental hormones in the regulation of placental and fetal growth in this intriguing adolescent paradigm are discussed. Impaired placental growth, particularly of the fetal component of the placenta, is the primary constraint to fetal growth during late gestation in the overnourished dams and nutritional switch-over studies indicate that high Nutrient intakes during the second two-thirds of pregnancy are most detrimental to pregnancy outcome. In addition, it may be possible to alter the Nutrient transport function of the growth-restricted placenta in that the imposition of a catabolic phase during the final third of pregnancy in previously rapidly growing dams results in a modest increase in lamb birth weight.
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Nutrient Partitioning during pregnancy adverse gestational outcome in overnourished adolescent dams
Special issue. Summer Meeting of the Nutrition Society University of Glasgow UK 29 June-2 July 1999., 2000Co-Authors: Jacqueline WallaceAbstract:Appropriate Nutrient Partitioning between the maternal body and gravid uterus is essential for optimum fetal growth and neonatal survival, and in adult sheep Nutrient Partitioning during pregnancy generally favours the conceptus at the expense of the dam. However, recent studies using an overnourished adolescent sheep model demonstrate that the hierarchy of Nutrient Partitioning during pregnancy can be dramatically altered in young growing females. Overnourishing the adolescent dams to promote rapid maternal growth throughout pregnancy results in a major restriction in placental mass and leads to a significant decrease in birth weight relative to moderately-fed adolescents of equivalent gynaecological age. High maternal feed intakes are also associated with an increased incidence of non-infectious spontaneous abortion, a reduction in gestation length and colostrum production, and a higher incidence of neonatal mortality. The present paper examines the putative role of a variety of endocrine regulators of Nutrient Partitioning in this unusual model system, where the dam is overnourished while the stunted placenta restricts Nutrient supply to the fetus. The central role of nutritionally-mediated alterations in placental growth and development in setting the subsequent pattern of Nutrient Partitioning between the maternal body, placenta and fetus is examined, and critical periods of sensitivity to alterations in maternal nutritional status are defined. Finally, the consequences of this form of inappropriate Nutrient Partitioning on the growth and development of the fetus and neonate are described with particular emphasis on the reproductive axis.
R P Aitken - One of the best experts on this subject based on the ideXlab platform.
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the effect of overnourishing singleton bearing adult ewes on Nutrient Partitioning to the gravid uterus
British Journal of Nutrition, 2005Co-Authors: Jacqueline Wallace, John S Milne, R P AitkenAbstract:Overnourishing the singleton-bearing adolescent sheep throughout pregnancy promotes maternal tissue synthesis at the expense of the Nutrient requirements of the gravid uterus. Consequently, the growth of the placenta is impaired and results in the premature delivery of low-birth-weight lambs relative to moderately fed adolescents of equivalent age. To establish if this phenomenon is unique to the growing animal, singleton pregnancies to a single sire were established by embryo transfer into primiparous adult ewes who had attained the normal mature body size for their genotype. Thereafter ewes were offered a maintenance or a high level of a complete diet throughout gestation. High maternal intakes resulted in elevated maternal insulin, no significant change in growth hormone or glucose, and attenuated progesterone and NEFA concentrations. Live weight gain during the first 93 d of gestation was 48 and 244 g/d, and adiposity score at term was 2.4 and 3.7 in the maintenance and high groups, respectively (P<0.001). In spite of achieving levels of adiposity similar to overnourished adolescents, placental (477 (sem 30) v. 518 (sem 41) g) and fetal (5190 (sem 320) v. 5420 (sem 250) g) weights were equivalent in maintenance and high groups. Gestation length was shorter (P<0.01) and colostrum yield at parturition lower (P<0.05) in high v. maintenance dams. Thus, adult sheep appear to be relatively insensitive to the oversupply of Nutrients during pregnancy and have the ability to meet the Nutrient requirements for normal conceptus growth in spite of their increased adiposity.
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maternal growth hormone treatment from day 35 to 80 of gestation alters Nutrient Partitioning in favor of uteroplacental growth in the overnourished adolescent sheep
Biology of Reproduction, 2004Co-Authors: Jacqueline Wallace, John S Milne, R P AitkenAbstract:Abstract Overnourishing the pregnant adolescent ewe promotes maternal tissue synthesis at the expense of placental growth and leads to a major reduction in lamb birth weight at term. Growth hormone (GH) secretion is attenuated in these overnourished dams and the maternal somatotrophic axis may play a key role in coordinating Nutrient usage in the pregnant adolescent. Thus we investigated whether increasing maternal GH during the period of rapid placental proliferation alters Nutrient Partitioning between the maternal, placental, and fetal tissues as assessed at Day 81 of gestation. Adolescent recipient ewes were implanted with singleton embryos, derived from superovulated dams and a single sire on Day 4 postestrus. Thereafter, the ewes were offered either a high (H) or moderate intake (M) of the same complete diet. From Day 35 to 80 of gestation, ewes were either injected twice daily (s.c. at 0800 and 1800 h) with recombinant bovine GH (bGH, 0.14 mg/kg live weight/day) or remained untreated (n = 8 ewes pe...
