Integrating nutritional and reproductive models to improve reproductive efficiency in dairy cattle

S.L. Shields, H. Woelders, H.M.T. Boer, S. Röblitz, C. Stötzel, J. Plöntzke, J.P. McNamara

Research output: Contribution to journalAbstractAcademic

Abstract

The objective was to integrate 2 existing mechanistic, dynamic models of nutritional and reproductive processes in the dairy cow. The objective of this research model is to be suitable for evaluation of data, concepts, and hypotheses regarding underlying genetic, nutritional, and physi-ological control of reproduction. A model of metabolism (Molly, UC Davis); which describes metabolism of glucose, amino acids, and fatty acids in tissues at an aggregated metabolic pathway level was integrated with a model of reproductive processes which describes growth and decay of the follicles and corpus luteum, gonadotropin releasing hor-mone, follicle stimulating hormone, luteinizing hormone, progesterone, estrogen, oxytocin, and prostaglandin F2α over time. The nutritional and reproductive processes are integrated at specific points: glucose, IGF-I, leptin and growth hormone affect rates of follicle stimulating hormone, luteinizing hormone, and follicular growth. Degradation of estrogen and progesterone is a function of metabolic clearance rate (MCR); (MCR progesterone, ng/μl = 2.6455 - 0.1606(DMI)2 - 0.5896(DMI) r2 = 0.9964). Progesterone affects probability of embryo survival (% survival = 51.74 + 4.18 (ng/ml) r2 = 0.9943). Pulse frequency of LH is a function of leptin (LH pulses/8h = 0.591 + 0.0015 (ng/ml)5 - 0.025(ng/ml)4 + 0.144(ng/ml)3 - 0.319(ng/ml)2 + 0.237(ng/ml) r2 = 0.65). The probability of ovulation is a function of dominant follicle diameter (probability, % = 465.6 - 0.72(diam.)3 + 21.1(diam.)2- 180.0 (diam.); r2 = 0.99). Probability of first service conception is a function of IGF1: (prob., % = 11.36 + 10.42(IGF1 ng/ml) r2 = 0.97). Changing energy intake or milk production causes a pattern and direction of response in reproductive processes consistent with literature values. Increased meta-bolic rate decreases estrogen and progesterone concentration, reduces the ovulatory surge and decreases embryo survival. This research model should be useful to frame specific hypotheses on control of reproductive processes by genetic and nutritional driven mechanisms.
Original languageEnglish
Pages (from-to)46-46
JournalJournal of Dairy Science
Volume95
Publication statusPublished - 2012

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