Plasma PGFM and progesterone concentrations, luteolysis moment and estrous cycle length in Nelore cows submitted to uterine biopsies

Abstract

In this study, endometrial samples were collected in 14 Nelore cows on days zero (ovulation), five, nine, thirteen and nineteen of the estrous cycle (biopsy group), and in 15 females these collections weren't performed (control group). Biopsies were done on the uterine horn endometrium contralateral to the ovary with corpus luteum. Blood samples were taken at -24, -16, -8, 0 +8, +16 and +24 hours in relation to progesterone drop (<1ng/mL, zero moment) and evaluated for 13, 14-dihydro-15-keto prostaglandin F2-alpha (PGFM) by radioimmunoassay (RIA). Plasma progesterone concentration was determined by RIA every 24 hours. Data were analyzed by ANOVA using the PROC GLM and MIXED of the SAS. The mean value for PGFM during the entire period evaluated was greater in the biopsy group. The mean concentration of PGFM at moment zero was not different between the groups; the mean concentration of PGFM was higher in the biopsy group before and after the drop in progesterone level. The maximum mean concentration observed was not different between the groups; however, the mean minimum concentration was different with high values in the biopsy group. Although the PGFM concentrations were higher in the biopsy group, the biopsy and control groups had similar length of estrous cycle showing that repeated endometrial biopsy on the side contralateral to the ovary with corpus luteum does not affect luteolysis and the length of the estrous cycle.

Effect of endometrial biopsy on uterine health in tropically adapted beef cattle

“…While it appears that biopsy does not have a substantial negative effect on oestrous cycle length or conceptus survival there is release of endometrial PGF2α after the procedure. Martin et al, (2015) found that on the day of luteolysis (Day 18), PGFM concentrations in biopsied heifers were higher compared to non-biopsied controls (83.4 ±16.3 vs. 55.4 ±16.4, respectively P<0.05). …”

“…While most of the studies have shown CL lifespan is not affected by either single or repeated endometrial biopsies during an oestrous cycle (Mann and Lamming, 1994, Boos et al, 1996, Katagiri and Takahashi, 2004 or during early pregnancy (Meikle et al, 2005, Martin et al, 2015 one study showed oestrous cycles may be shortened after performing two endometrial biopsies in the same cycle (Zaayer and Van der Horst, 1986). While it appears that biopsy does not have a substantial negative effect on oestrous cycle length or conceptus survival there is release of endometrial PGF2α after the procedure.…”

“…Some studies have administrated cyclooxygenase inhibitors before procedures such as ET or EB to suppress endogenous release of PGF2α synthesis in response to uterine manipulation and the potential subsequent induction of luteolysis (Scenna et al, 2005, Aguiar et al, 2013, Martin et al, 2015, Lopes et al, 2015.Cyclooxygenase enzymes (COX 1 and COX2) are responsible for the synthesis of prostaglandins from arachidonic acid (AA) that contribute to the acute inflammatory response. Cyclooxygenase inhibitors (non-steroidal anti-inflammatory drug NSAIDs, Flunixin Meglumine, Meloxicam) competitive bind and inactivate COXs site preventing catalysis of A.A to prostaglandins (Ricciotti and FitzGerald, 2011).Overall, these studies suggested that the administration of COX inhibitors at the time of the procedure had shown no effect on subsequent CL lifespan or oestrous cycle length (Martin et al, 2015) or conceptus survival (Geary et al, 2010, Aguiar et al, 2013.…”

“…Cyclooxygenase inhibitors (non-steroidal anti-inflammatory drug NSAIDs, Flunixin Meglumine, Meloxicam) competitive bind and inactivate COXs site preventing catalysis of A.A to prostaglandins (Ricciotti and FitzGerald, 2011).Overall, these studies suggested that the administration of COX inhibitors at the time of the procedure had shown no effect on subsequent CL lifespan or oestrous cycle length (Martin et al, 2015) or conceptus survival (Geary et al, 2010, Aguiar et al, 2013.…”

“…In some studies that had concluded that oestrus length is not affected after biopsy, there is lack of information about the site of endometrial collection Lamming, 1994, Katagiri andTakahashi, 2004) while other studies had collected biopsies from the horn contralateral to the CL avoided PGF2α reaching the functional CL , Martin et al, 2015. Martin et al, (2015) showed administration of COX inhibitors prior to repeated EB of Nellore cows at days zero (ovulation), five, nine, thirteen and nineteen from the horn contralateral to the CL, did not change oestrus length. These studies show conclusively that biopsy from the horn contralateral to CL does not induce luteolysis.…”