Preparation of Broodmares for Breeding Season - Part 3: Pre-Breeding Evaluation
written by: Agata Zagrajczuk (PhD in Animal Reproduction)
The pre-breeding evaluation is made up of the following series of steps: Firstly, an external perineal conformation exam (vagina-anus angulation) evaluates the physical anatomy of the mare’s reproductive organs.
Anatomically, if the perineal region is significantly sloped from the vertical axis, the mare’s internal reproductive tract may potentially be contaminated with faeces. The notable symptoms include “windsucking’ (i.e. pneumovagina) or urine “pooling” (ie. urovagina). The possible consequence of this condition is an inflammation of the vagina and/or uterus, suppressing conception. Dependent upon the severity, some of these misaligned anatomical conditions may be corrected through veterinary surgical intervention.
There are few methods of uterine health evaluation:
low- and high-volume lavage and
The most popular method is an endometrial (uterine) swab culture combined with a cytology smear, to determine the presence or absence of possible pathogens within the uterus. The endometrial swab culture alone is not a reliable method, particularly when results are negative. The cytology smear identifies inflammatory cells, even if the mare does not present clinical symptoms and/or the microbiology culture is negative.
Both examinations should be performed during the oestrus phase, when immunological defences are at their greatest level, and consequently the risk of a secondary infection is at its lowest. Two types of smear devices are available for cell harvesting:
the traditional swab and
the cytology brush (superior choice)
Regardless, of the swab or brush used, it should be “double-guarded”, as to prevent accidental contamination with vaginal cells, and subsequently a false diagnostic result.
An alternative to the swab / brush procedures are low- and high-volume lavages, capturing cell sedimentation that is used for the diagnostic evaluation. This procedure is a more labour-intensive method; however, the diagnostic may prove to be more accurate.
The endometrial biopsy is the most advanced among all these methods. It allows not only the precise evaluation of inflamed and epithelial cells and/or of the microbiological culture, but also provides an estimate of any endometrial structures present as well as a potential endometrial fibrosis.