Aetiology and pathogenesis of cystic ovarian follicles in dairy cattle: a review

Abstract

-Cystic ovarian follicles (COF) are an important ovarian dysfunction and a major cause of reproductive failure in dairy cattle. Due to the complexity of the disorder and the heterogeneity of the clinical signs, a clear definition is lacking. A follicle becomes cystic when it fails to ovulate and persists on the ovary. Despite an abundance of literature on the subject, the exact pathogenesis of COF is unclear. It is generally accepted that disruption of the hypothalamo-pituitary-gonadal axis, by endogenous and/or exogenous factors, causes cyst formation. Secretion of GnRH/LH from the hypothalamus-pituitary is aberrant, which is attributed to insensitivity of the hypothalamus-pituitary to the positive feedback effect of oestrogens. In addition, several factors can influence GnRH/LH release at the hypothalamo-pituitary level. At the ovarian level, cellular and molecular changes in the growing follicle may contribute to anovulation and cyst formation, but studying follicular changes prior to cyst formation remains extremely difficult. Differences in receptor expression between COF and dominant follicles may be an indication of the pathways involved in cyst formation. The genotypic and phenotypic link of COF with milk yield may be attributed to negative energy balance and the associated metabolic and hormonal adaptations. Altered metabolite and hormone concentrations may influence follicle growth and cyst development, both at the level of the hypothalamus-pituitary and the ovarian level.cystic ovarian follicles / pathogenesis / hypothalamus-pituitary / ovary / negative energy balance

Incidence of ovarian follicular cysts and their effect on reproductive performance in dairy cows: A case study in Mexico

“…In academic literature, it is debated whether ovarian follicular cysts (OFC) in dairy cows should be considered pathological or innocuous (Vanholder et al 2006). Up to the 1980s, classic clinical signs in cows with OFC as described in the literature were: short cycles, irregular estrus, nymphomania, masculinization, and relaxation of the pelvic ligaments (Kesler and Garverick 1982).…”

“…Up to the 1980s, classic clinical signs in cows with OFC as described in the literature were: short cycles, irregular estrus, nymphomania, masculinization, and relaxation of the pelvic ligaments (Kesler and Garverick 1982). However, dairy cows that currently develop OFC only present anestrus (Peter 2004, Vanholder et al 2006. Therefore, this ovarian condition is more often referred to as ovarian follicular cysts, and less as cystic ovarian disease.…”

“…According to Vanholder et al (2006), OFC can be defined as: follicles with a minimum diameter of 20 mm, present in one or both ovaries in the absence of a corpus luteum, and which interfere with cyclicity. Moreover, OFC are dynamic structures that may undergo regression and be replaced by new follicles, which later become OFC (Hamilton et al 1995).…”

Cytoskeletal proteins in the follicular wall of normal andcystic ovaries of sows

“…Possibly, the stress contributes with the formation of the CFD in sows (Scholten & Liptrap 1978). Some researchers cite endocrine disorders affecting the hypothalamo-hypophyseal axis related to development of the ovarian cysts in sows (Scholten & Liptrap 1978) and cows (Garverick 1997, Silvia et al 2002, Vanholder et al 2006. Recent investigation revealed that apoptosis and cell proliferation were altered in swine cystic follicles (Sun et al 2012).…”

Post-treatment sequential ultrasound imaging of follicular cyst in a crossbred dairy cow

“…Follicular cysts in dairy cattle are defined as follicles with a diameter greater than or equal to 2 cm that are present on one or both ovaries in the absence of any luteal tissue and that clearly interfere with normal ovarian cyclicity [1]. The condition has a huge negative impact on fertility and overall productivity, owing to its effects on reproductive parameters such as calving to conception interval, number of services per conception, and pregnancy rate [2,3].…”