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

Abstract

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 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. AMS MSC 2000: 92C42, 92C30, 90C31, 65L09

Mathematical analysis of a model for the growth of the bovine corpus luteum

“…While the role of ovarian physiology and, in particular, CL growth, development and function have been the main focus of many experimental studies (Lucy, 2001;Mann and Lamming, 2001;Perry et al, 2005;Robinson et al, 2006), mathematical modelling of this biological aspect is scarce. Existing models have focused on hormone production and its regulation during the bovine oestrous cycle (Boer et al, 2011;Pring et al, 2012), while Meier et al (2009) concentrated on progesterone production. The key hormone, that induces the formation of the CL as well as likely to play an important role in initiating luteal angiogenesis is luteinising hormone (LH) (Robinson et al, 2008).…”

Advances in computational modeling approaches of pituitary gonadotropin signaling

“…The efforts in developing models of hormone interactions mainly regard the hypothalamic-pituitaryovarian axis in women. Nevertheless, several approaches have tackled similar issues in different breeding [26] or laboratory species [27]. For instance, in line with the approach followed in [23], a model based on DDE has been designed in [26] for the bovine species, whose ovarian physiology is rather close to human ovarian physiology (roughly comparable duration of the ovarian cycle, existence of follicular waves and similar size of the ovarian follicles).…”

Decision Support Systems Development for an Artificial Insemination Project in Community Based Precision Livestock Farming

“…A flock of follicles materialized on the fourth day subsequent to the exuviation of the mature eggs. Each follicle wave is initiated by the release of follicle stimulating hormone (FSH) from the anterior pituitary [27]. According to the literature, the duration of estrus cycle varies.…”

“…Forde and Beltman [19], for example, argued that the normal duration of estrus cycle is between 18 to 24 days. While Boer and his associates [27] suggested the cycle between 20 to 22 days. Despite a single consensus on the normal duration of the estrus cycle in post-partum female cattle has not been concluded, scholars agreed on the mechanism and phases of estrus cycle.…”