Effect of Endometrial Sampling Procedures on Subsequent Pregnancy Rate of Cattle

Abstract

Endometrial infections are a common cause of reproductive loss in cattle. Accurate diagnosis is important to reduce the economic losses caused by endometritis. A range of sampling procedures have been developed which enable collection of endometrial tissue or luminal cells or uterine fluid. However, as these are all invasive procedures, there is a risk that sampling around the time of breeding may adversely affect subsequent pregnancy rate. This systematic review compared the pregnancy rates (PR) of cattle which underwent uterine lavage (UL), cotton swab (CS), cytobrush (CB), cytotape (CT), or endometrial biopsy (EB) sampling procedures with those that were not sampled. Using the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) protocol, relevant databases, including Pubmed, Web of Science, CAB Abstracts, VetMed Resource–Ruminants, and Scopus, were searched. The outcome measured was the pregnancy rate after the collection of endometrial sample(s). Seven studies, involving a total of 3693 cows, fulfilled the inclusion criteria for the systematic review and allowed the comparison of PR between sampled (n = 1254) and non-sampled cows (n = 2409). The results of the systematic review showed that endometrial sampling procedures can be performed before breeding or shortly after insemination without adversely affecting pregnancy rates in cattle. However, further studies are needed to validate this information.

The microbiota of uterine biopsies, cytobrush and vaginal swabs at artificial insemination in Norwegian red cows

“…Few sampled animals (41.7%) maintained their pregnancy at 56 days after AI, comparing our results to the average non-return-rate in NR of 72.9% [25]. Recently, Ramirez-Garzon et al [56] published a review on the effect of endometrial sampling procedures on the subsequent pregnancy rate in cattle. They concluded that endometrial biopsy does not have a negative effect on fertility.…”

Correlation between microbial characteristics and reproductive status of the yak uterus based on macrogenomic analysis

“…Three healthy female yaks aged 4-6 years were selected for each of the four estrus stages: proestrus, estrus, metestrus, and diestrus. Samples were collected using the intrauterine cotton swab (CS) method [14,18,19]. Briefly, a sterile disposable swab was attached to the tip of a bovine artificial insemination (AI) gun and wrapped with an external protective plastic sheath.…”

“…Their study indicated that microbial changes might lead to reproductive diseases. However, collecting live samples from animal uteri is difficult and may introduce pathogenic bacteria, causing endometrial infection and even loss of reproductive ability in cows [14]. Therefore, studying the diversity of the uterine microbiota during the animal estrous cycle may provide a basis for revealing microbial involvement in reproductive regulation.…”