A simple mathematical model of the bovine estrous cycle: Follicle development and endocrine interactions

• Published in: Journal of theoretical biology 2011-06, Vol.278 (1), p.20-31
• Main Authors: Boer, H.M.T., Stötzel, C., Röblitz, S., Deuflhard, P., Veerkamp, R.F., Woelders, H.
• Format: Article
• Language: English
• Subjects: Animals; Cattle; chemical-reaction systems; Computer Simulation; Cow; dairy-cows; Differential equations; Dinoprost - blood; dominant follicles; Endocrine System - metabolism; Estradiol - blood; Estrous Cycle - metabolism; Female; Follicle Stimulating Hormone - blood; Gonadotropin-Releasing Hormone - metabolism; Hormone patterns; Humans; Inhibins - metabolism; Life Sciences; Luteinizing Hormone - blood; luteolytic signal; menstrual-cycle; Models, Biological; Ovarian Follicle - growth & development; Ovarian Follicle - metabolism; ovarian-follicles; peripheral plasma; plasma progesterone levels; Progesterone - blood; Reproduction; stimulating-hormone; suckled beef-cows; Systems biology; Time Factors
• ISSN: 0022-5193; 1095-8541
• DOI: 10.1016/j.jtbi.2011.02.021

Bovine fertility is the subject of extensive research in animal sciences, especially because fertility of dairy cows has declined during the last decades. The regulation of estrus is controlled by the complex interplay of various organs and hormones. Mathematical modeling of the bovine estrous cycle could help in understanding the dynamics of this complex biological system. In this paper we present a mechanistic mathematical model of the bovine estrous cycle that includes the processes of follicle and corpus luteum development and the key hormones that interact to control these processes. The model generates successive estrous cycles of 21 days, with three waves of follicle growth per cycle. The model contains 12 differential equations and 54 parameters. Focus in this paper is on development of the model, but also some simulation results are presented, showing that a set of equations and parameters is obtained that describes the system consistent with empirical knowledge. Even though the majority of the mechanisms that are included in the model are based on relations that in the literature have only been described qualitatively (i.e. stimulation and inhibition), the output of the model is surprisingly well in line with empirical data. This model of the bovine estrous cycle could be used as a basis for more elaborate models with the ability to study effects of external manipulations and genetic differences.