Influence of uterine bacterial contamination after parturition on ovarian dominant follicle selection and follicle growth and function in cattle

Abstract

First postpartum dominant follicles are preferentially selected in the ovary contralateral to the previously gravid uterine horn. The aim of the present study was to test the hypothesis that uterine bacterial contamination alters the location of ovarian follicle emergence and selection, and inhibits follicle growth and function. Swabs were collected from the uterine body lumen of cattle on days 7, 14, 21 and 28 after parturition. Bacteria were identified by aerobic and anaerobic culture; bacterial growth was scored semiquantitatively and animals were categorized into standard or high bacterial contamination categories on the basis of the number of colonies detected. Follicular growth and function were monitored by daily transrectal ultrasonography, and estimation of plasma FSH, oestradiol and progesterone concentrations. There was no effect of bacterial contamination on plasma FSH concentration profiles or emergence of the ovarian follicle wave. When uterine bacterial growth scores were high on day 7 or day 21 after parturition, fewer first (1/20 versus 15/50; P < 0.05) or second (1/11 versus 13/32; P < 0.05) dominant follicles were selected in the ipsilateral compared with the contralateral ovary, respectively. The diameter of the first dominant follicle was smaller in animals with a high day 7 bacterial score (P < 0.001), dominant follicle growth was slower (P < 0.05) and oestradiol secretion was decreased (P < 0.05). The present study provides evidence for an effect of the uterus on the ovary after parturition, whereby uterine bacteria have a contemporaneous localized effect on ovarian follicle selection and subsequent growth and function, but not on initial emergence.

Innate immunity and inflammation of the bovine female reproductive tract in health and disease

“…Escherichia coli infect the endometrium within a week of parturition, followed in subsequent weeks by Trueperella pyogenes and a range of anaerobic bacteria that include Fusobacterium, Prevotella and Bacteriodes species (Bonnett et al 1991, Sheldon et al 2002. Although not the focus of the present manuscript, it is important to note that bovine herpesvirus 4 is also tropic for endometrial stromal cells and causes postpartum uterine disease in some animals (Donofrio et al 2007).…”

“…Whilst links between inflammation in the endometrium and infertility are intuitive, it was less obvious whether uterine infections might affect ovarian function. However, in dairy cattle, uterine disease is associated with LPS in follicular fluid, slower growth of dominant follicles, lower peripheral plasma concentrations of oestradiol and increased risks of anoestrus or cystic ovarian disease (Opsomer et al 2000, Sheldon et al 2002. The mechanisms underlying these observations are now emerging.…”

“…Indeed, treatment of ewes with LPS suppresses the expression of genes encoding GNRH receptor (GNRHR) and LHb (Herman et al 2013b). However, the peripheral plasma concentrations of follicle-stimulating hormone are unaffected by uterine disease in cattle (Sheldon et al 2002).…”

Postpartum Uterine Infections in Cows and Factors Affecting it– A Review

“…Resumption of cyclicity also occurs during this interval, with the first ovulation occurring around days 40 to 45 postpartum (Cengic et al, 2012). This interval can be affected by nutrition, body condition, parity and can be extended due to uterine disease (Sheldon et al, 2002).…”

“…Bacteria can be cultured from samples collected from uterine lumen of dairy cattle in the first 2 weeks after parturition without appearance of any apparent clinical signs (Sheldon et al, 2002). Polat et al, (2009) reported that 10-17% of cows have pathogenic bacteria two weeks post-calving while Sheldon (2007) found that intensively managed dairy cattle often have bacterial uterine contamination rates of 90 to 100% within the first two weeks postpartum.…”