Ovarian Cyst, Dairy cows, Stress

Ovarian Cyst

Ovarian cyst is an abnormal follicular structure that forms due to ovulation failure, reaching larger diameter than ovarian follicle and persists for ≥10 days. This structure may regress spontaneously, stay permanently or be luteinized (Ball & Peter, 2004; Noakes et al., 2018), (Figure. 1).

Ovarian cyst is more common in dairy than beef cows, especially in high milk production cows. It often occurs during the postpartum period (Hafez & Hafez, 2000; Noakes et al., 2018, Peter et al., 2009). Peter et al. (2018) consider the ovarian cyst as a development of anestrous case of persistence structures of dominant follicles, but Noakes et al. (2018) do not consider the importance of CL absence in this case.

The failure in luteinizing hormone (LH) releasing mechanism is the most evident cause of ovarian cyst which is not related to deficiency in Gonadotropin-releasing hormone (GnRH) but it is related to low sensitivity of hypothalamic-pituitary axis to elevated secretion of estradiol (Hafez & Hafez, 2000), this low sensitivity is caused by stress factors; that execute their effects by releasing adrenal cortisol (Hafez & Hafez, 2000; Huber et al., 2020; Noakes et al., 2018). Generally cows with ovarian cyst show nymphomania, masculine behaviors or anestrous due to modifications in steroidogenesis (Ball & Peter, 2004; Noakes et al., 2018).

 The ovarian cyst can be diagnosed by rectal palpation and/or by ultrasonography. It is recommended to verify the follicular abnormalities (Inactive ovaries, ovarian cyst and….etc) twice by ultrasonography with an interval of seven days (Noakes et al., 2018; Peter et al., 2009).

 There are different treatments that are based on exogenous GnRH and/or prolonged progesterone (P4) application (Noakes et al., 2018; Ball & Peter, 2004). Bearing in mind that the treatment should be applied as early as possible.

Figure. 1. Ovarian cyst, (a) Abattoir ovary, (b) Luteinized ovarian cyst (ultrasonography) (Personal archive)

References

 Ball, P. J. H., & Peters, A. R. (2004). Reproduction in Cattle (3rd ed.). Wiley-Blackwell.

 Hafez, E. S. E., & Hafez, B. (Eds.). (2000). Reproduction in farm animals. John Wiley & Sons.

 Huber, E., Notaro, U. S., Recce, S., Rodríguez, F. M., Ortega, H. H., Salvetti, N. R., & Rey, F. (2020). Fetal programming in dairy cows: effect of heat stress on progeny fertility and associations with the hypothalamic-pituitary-adrenal axis functions. Animal Reproduction Science, 106348.

 Noakes, D. E., Parkinson, T. J., & England, G. C. W.(2018). Arthur’s Veterinary Reproduction and Obstetrics (10th ed.). Saunders Ltd.

 Peter, A. T., Vos, P. L. A. M., & Ambrose, D. J. (2009). Postpartum anestrus in dairy cattle. Theriogenology, 71(9), 1333-1342.

Please read and leave your comment,
Best regards,