Cytological and bacteriological sampling from filters used for embryo recovery to evaluate the uterine status of donor mares.

The research aims to determine the presence of bacteria and inflammatory cells in the uterus of mares following embryo flushing. The findings suggest that despite the absence of clinical signs, an assessment of uterine fluids post-flushing could provide useful information on the uterine environment and help predict the success of embryo transfers.

Objective of the study

• The primary objective of the study was to assess the presence of bacteria and inflammatory cells in the uterus of donor mares following a process known as embryo flushing – a procedure used to collect embryos for transfer. The researchers aimed to determine whether such an assessment could provide useful insights into the uterine environment, and in turn, the likelihood of successful embryo transfers.

Methodology

• The researchers began by selecting a group of 8 mares showing clear signs of endometritis, an inflammation of the uterine lining. Samples were taken from these mares using cotton swabs prior to and after uterine flushing, and both sets of samples were subjected to bacterial and cytological analysis.
• A larger group of 20 donor mares also underwent the same process. Following embryo flushing and collection, the fluid remaining in the uterine filter was evaluated for bacterial and cytological content. A sterile cotton swab was used to collect samples from the filter mesh for bacterial culture.

Findings

• The study yielded an embryo recovery rate of 30% (6 out of 20 mares). One of the samples contained Escherichia coli while the other five samples were negative for bacterial culture.
• Overall, bacterial growth was determined in three samples, but no inflammatory cells were detected. This indicated that while bacteria can be found in samples collected following embryo flushing, no inflammation was present in the uterus of mares from which embryos were successfully recovered.

Implications

• The researchers concluded that, despite the absence of clinical signs, assessing the filter and uterine fluids post-flushing may yield valuable information on uterine status at the point of embryo collection.
• However, they cautioned that such cytological and/or bacteriological sampling may not provide accurate predictions of embryo recovery success in the absence of clear clinical signs.