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A Redefinition Of The Representation Of Mammary Cells And Enzyme Activities In A Lactating Dairy Cow Model.

M. Hanigan, A. Ríus, E. Kolver, C. Palliser
Published 2007 · Biology, Medicine

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The Molly model predicts various aspects of digestion and metabolism in the cow, including nutrient partitioning between milk and body stores. It has been observed previously that the model underpredicts milk component yield responses to nutrition and consequently overpredicts body energy store responses. In Molly, mammary enzyme activity is represented as an aggregate of mammary cell numbers and activity per cell with minimal endocrine regulation. Work by others suggests that mammary cells can cycle between active and quiescent states in response to various stimuli. Simple models of milk production have demonstrated the utility of this representation when using the model to simulate variable milking and nutrient restriction. It was hypothesized that replacing the current representation of mammary cells and enzyme activity in Molly with a representation of active and quiescent cells and improving the representation of endocrine control of cell activity would improve predictions of milk component yield. The static representation of cell numbers was replaced with a representation of cell growth during gestation and early lactation periods and first-order cell death. Enzyme capacity for fat and protein synthesis was assumed to be proportional to cell numbers. Enzyme capacity for lactose synthesis was represented with the same equation form as for cell numbers. Data used for parameter estimation were collected as part of an extended lactation trial. Cows with North American or New Zealand genotypes were fed 0, 3, or 6 kg of concentrate dry matter daily during a 600-d lactation. The original model had root mean square prediction errors of 17.7, 22.3, and 19.8% for lactose, protein, and fat yield, respectively, as compared with values of 8.3, 9.4, and 11.7% for the revised model, respectively. The original model predicted body weight with an error of 19.7% vs. 5.7% for the revised model. Based on these observations, it was concluded that representing mammary synthetic capacity as a function of active cell numbers and revisions to endocrine control of cell activity was meritorious.
This paper references
Effects of genotype and diet on milksolids production, body condition, and reproduction of cows milked continuously for 600 days
E. Kolver (2006)
Milk production from grass silage diets: strategies for concentrate allocation
K. Aston (1995)
Endocrine profiles of cows undergoing extended lactation in relation to the control of lactation persistency.
A. Sorensen (2002)
Metabolism of the lactating cow. II. Digestive elements of a mechanistic model.
R. L. Baldwin (1987)
Modeling the effect of energy status on mammary gland growth and lactation.
I. Vetharaniam (2003)
Validation of indirect measures of body fat in lactating cows.
S. Waltner (1994)
Metabolism of the lactating cow. III. Properties of mechanistic models suitable for evaluation of energetic relationships and factors involved in the partition of nutrients.
R. L. Baldwin (1987)
Metabolism of the lactating cow. I. Animal elements of a mechanistic model.
R. L. Baldwin (1987)
Adipose tissue metabolism and its role in adaptations to undernutrition in ruminants.
Y. Chilliard (2000)
Study of the lactation curve in dairy cattle on farms in central Mexico.
D. Val-Arreola (2004)
Reduced insulin-like growth factor-I after acute feed restriction in lactating dairy cows is independent of changes in growth hormone receptor 1A mRNA.
Y. Kobayashi (2002)
Milk production from pasture.
Holmes Cw (1987)
Arginine infusion stimulates prolactin, growth hormone, insulin, and subsequent lactation in pregnant dairy cows.
B. Chew (1984)
Principles and practices
W. C. Kvaraceus (1959)
Nutritional modulation of the somatotropin/insulin-like growth factor system: response to feed deprivation in lactating cows.
M. A. McGuire (1995)
Mammary cell turnover and enzyme activity in dairy cows: effects of milking frequency and diet energy density.
J. Nørgaard (2005)
Estimation of parameters describing lipid metabolism in lactation: challenge of existing knowledge described in a model of metabolism.
J. Mcnamara (2000)
Evaluation of alternative equations for prediction of intake for Holstein dairy cows.
D. K. Roseler (1997)
The lactation curve in cattle: a mathematical model of the mammary gland
H. Neal (1983)
Management of photoperiod in the dairy herd for improved production and health.
G. Dahl (2003)
Mathematical Modelling in Animal Nutrition
E. Kebreab (2008)
Neuroregulation of growth hormone secretion in domestic animals.
C. Mcmahon (2001)
Effects of Milking Frequency and Selection for Milk Yield on Productive Efficiency of Holstein Cows
M. Barnes (1990)
Nutrient Digestion and Utilization in Farm Animals
E. Kebreab (2006)
The Lactogenic Preparations from the Anterior Pituitary and the Increase of Milk Yield in Cows
G. J. Asimov (1937)
Effect of photoperiod on hepatic growth hormone receptor 1A expression in steer calves.
P. E. Kendall (2003)
Modeling the interaction of milking frequency and nutrition on mammary gland growth and lactation.
I. Vetharaniam (2003)
Placental transport of nutrients and its implications for fetal growth.
A. Bell (1999)
Response of somatomedins (IGF-I and IGF-II) in lactating cows to variations in dietary energy and protein and treatment with recombinant n-methionyl bovine somatotropin.
M. A. McGuire (1992)
Central infusion of leptin into well-fed and undernourished ewe lambs: effects on feed intake and serum concentrations of growth hormone and luteinizing hormone.
C. Morrison (2001)
An ingredient-based input scheme for Molly
M. Hanigan (2005)
Metabolic models of ruminant metabolism: recent improvements and current status.
M. Hanigan (2006)
A model to describe growth patterns of the mammary gland during pregnancy and lactation.
J. Dijkstra (1997)
Effects of level of energy intake and energy demand on growth hormone, insulin, and metabolites in Targhee and Suffolk ewes.
P. Hatfield (1999)
Milk production from pasture principles and practices
Holmes Cw (2002)
Role of insulin in the regulation of mammary synthesis of fat and protein.
M. A. McGuire (1995)
Modeling ruminant digestion and metabolism.
R. L. Baldwin (1998)

This paper is referenced by
MODELLING ANIMAL SYSTEMS PAPER Evaluation of a mechanistic lactation model using cow, goat and sheep data
M. S. D Hanoa (2010)
Evaluation of a whole-farm model for pasture-based dairy systems.
P. Beukes (2008)
A new standard model for milk yield in dairy cows based on udder physiology at the milking-session level
Patrick Gasqui (2017)
Altering the representation of hormones and adding consideration of gestational metabolism in a metabolic cow model reduced prediction errors.
Mark D. Hanigan (2009)
High rates of mammary tissue protein turnover in lactating goats are energetically costly.
M. Hanigan (2009)
Analysis of pasture supplementation strategies by means of a mechanistic model of ruminal digestion and metabolism in the dairy cow.
John P. Mcnamara (2017)
Advances in predicting nutrient partitioning in the dairy cow: recognizing the central role of genotype and its expression through time.
N. Friggens (2013)
Characterisation of smallholder dairy production systems using animal welfare and milk quality
Bettie S. Kawonga (2012)
A redefinition of the modeled responses of mammary glands to once-daily milking.
A. G. Ríus (2019)
Modélisation systémique des performances des femelles de ruminants. Application au cas de la vache laitière.
O. Martin (2009)
La partition des nutriments entre fonctions physiologiques chez les vaches laitières dépend du génotype et de son expression dans le temps
Nicolas Charles Friggens (2013)
Review: To be or not to be an identifiable model. Is this a relevant question in animal science modelling?
R. Muñoz-Tamayo (2018)
Evaluation of a mechanistic lactation model using cow, goat and sheep data
J. Dijkstra (2010)
Revised digestive parameter estimates for the Molly cow model.
Mark D. Hanigan (2013)
Invited review: Experimental design, data reporting, and sharing in support of animal systems modeling research.
John P. Mcnamara (2016)
A review of the genetic and non-genetic factors affecting extended lactation in pasture-based dairy systems
Mary Abdelsayed (2015)
Proceedings of the 2013 Meeting of the Animal Science Modelling Group
James France (2013)
The Mathematical description of the lactation curve of ruminants: issues and perspectives
R. Steri (2010)
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