Endocrine Aspects of Uterine Involution in the Cow

Abstract

The postpartum period (PP) (querperium) is characterized by involution of the uterus and recyclicity of the ovarian functions to prepare the animal for a new pregnancy period. The time required for the genital organs to become normalised is influenced by breed, management including feeding regimens and environmental factors. This period is also strongly influenced by periparturient diseases such as dystocia, paresis (puerperalis), mastitis, endometritis, etc. The period is also influenced by several hormonal changes. During the postpartum period in the cow, a massive release of PGF2, occurs concomitantly with the uterine involution. In cows with retained foetal membranes (RFM), a second pulsatile release of PGF2, is seen concomitant with the growth and final elimination of bacteria. A similar pattern is seen in cows with induced parturitions with e.g. dexamethasone, indicating the occurrence of RFWendometritis as a consequence of the induction. The duration of these prostaglandin releases are negatively correlated to uterine involution in normal cows and positively correlated in cows with RFWendometritis respectively. As long as the release is maintained, the cow is unable to ovulate and it therefore seems likely that PGF2, or other products in the arachidonic acid cascade can inhibit the ovarian activity. Onset of ovarian cyclicity influences to a high degree the uterine involution, however most common is that the first ovarian cycle is shorter than seen during the normal oestrous cycle. The uterine involution process can be enhanced by treatments with exogenous PGF2,. No effect on uterine involution in healthy cows, or a slight positive effect, is seen after treatment with prostaglandin synthesis inhibitors (e.g. flunixin meglumine). The aim of this presentation is to review some of the knowledge of the interactions between the uterus and ovaries during the postpartum period in cattle.

Relationship of vaginal discharge characteristics evaluated by Metricheck device to metabolic status in postpartum dairy cows

“…In contrast, uterus inflammation stimulates the production of prostaglandins and activates arachidonic acid cascade (Kindahl et al, ; Mishra & Prakash, ). Thereby, plasma PGFM concentration in cows with endometritis after calving is maintained at high levels and decreases slowly to basal levels (Kindahl et al, ; Mishra & Prakash, ). In addition, Sheldon et al () showed that uterine infection after calving delayed the resumption of ovarian function in postpartum dairy cows, because bacterial contamination of the uterus suppressed dominant follicle growth and function.…”

Long-term alteration of follicular steroid concentrations in relation to subclinical endometritis in postpartum dairy cows1

“…(1 Uninfected (n = 21) 9.2 ± 0.5 5.2 ± 0.5 (n = 14) 7.0 ± 0.4 2.9 ± 0.4 42 scEndo (n = 12) 9.9 ± 0.6 5.9 ± 0.6 (n = 10) 7.7 ± 0.5 3.6 ± 0.5 d Uninfected (n = 22) 11.4 ± 0.5 7.4 ± 0.5 (n = 17) 7.9 ± 0.4 3.9 ± 0.4 63 scEndo (n = 15) 11.7 ± 0.6 7.7 ± 0.6 (n = 10) 7.7 ± 0.5 3.7 ± 0.5 Uterine involution is normally assumed to be completed by 4 to 5 wk postpartum (Kindahl et al, 1999). Hence, rebreeding is not recommended before 6 wk postpartum and so d 42 was chosen in this study as an optimal time to evaluate the effects of uterine health on ovarian follicular environment.…”

Intravaginally administered lactic acid bacteria expedited uterine involution and modulated hormonal profiles of transition dairy cows

“…Therefore, our search regarding the potential mechanisms underlying the smaller gravid horn and uterine body on d 14 focused on the health condition of the reproductive tract. Kindahl et al (1999) suggested a relationship between uterine health status and PGF 2α levels by indicating that pulsatile elevations of PGF 2α are negatively correlated with involution time in normal cows and positively correlated in cows with endometritis and retained placenta. Prostaglandin F 2α plays an important role in expediting postpartum uterine involution as well as clearing the fetal remnants and birth canal-ascended bacteria in the reproductive tract due to its efficacy in stimulating myometrial contractions.…”