Breeding the Problem Mare

Management of a problem breeder is one of the most challenging and potentially frustrating aspects of equine reproduction. Due to the high economic pressure within in the horse breeding industry, the care and insemination of your broodmare should not be left to chance. The careful selection of your broodmare is of increasing importance if you want to sell the offspring profitably. Therefore it is deemed necessary to perform a thorough reproductive examination to help decide on the probability of successful resolution of an underlying problem.

„When“ a mare is to be classified as as a problem breeder is at the discretion of the owner, veterinarian or breeding farm manager. Classically a mare should be regarded as a potential problem breeder if she fails to conceive to a fertile stallion on a well managed breeding farm on three or more cycles in one season. Mares expressing silent oestrus cycles, old maiden sport-horse mares and mares that suffer from post mating endometritis belong in the category as well.

A mare will never be a problem breeder just for one single reason; therefore the whole reproductive breeding record and all aspects of management should be examined. Data from i.e. previous Inseminations or covering dates, stallions, treatments, drugs, swab and cytology results, biopsy results, nutrition of the mare, parasite control and the medical history can help to find the reason for her problem. Each mare has to be looked at as an individual to develop a treatment plan for each mare.

Additional examinations

1. Low volume lavage

A low volume uterine flush is a rapid, accurate method of identifying mares with bacterial uterine infections and twice as sensitive as swab culture. Most clinicians are using guarded endometrial swab systems for uterine culture and cytology. Recent research has shown that multiple bacterial species assemble in plaques. When using a conventional swabbing system, the double guarded device will be carefully introduced through the cervix, whilst the mare is in season. The cotton bud at the end will absorb endometrial secretions. Using this method, infections can be missed because bacteria may be located focally, deep within the uterine body or uterine horns and then might not be detected by the endometrial swab. The recovered sample will be send to the laboratory in a special transport medium. By adapting a low-volume lavage, 60 ml of sterile fluid will be infused into the mare’s uterus through a sterile silicone catheter. The uterus is then manipulated by transrectal palpation and the fluid is drained into a sterile falcon tube by gravity. The recovered fluid flooded a larger surface of the mare’s endometrium and therefore flush culture doubles the ability to detect infected mares based on culture alone.

2. Cytology

The endometrial cytology is an important diagnostic tool for the breeding evaluation of the problem mare. With the help of a guarded device (Cytology brush) endometrial cells will be scraped of the surface of the endometrium and placed on a prepared slide for further staining. Samples can also be collected via low-volume lavage, where the recovered fluid has to be centrifuged afterwards.  Cytological specimens are evaluated for the presence of epithelial cells, debris, inflammatory cells, bacteria and yeast. The presence of neutrophil cells indicates a uterine infection. Cytology is a useful method in combination with dubious or negative swab results especially when the mare is clinically suspicio

3. Endometrial Biopsy

Endometrial biopsy is the most widely used technique for evaluating the severity of age related changes in the mare’s endometrium. There are two ways of biopsy sampling, the „blind“ method where the endometrial forceps is passed through the cervix and one or several tissue samples are collected from the uterine body and the base of the horns or under visual control, where the biopsy forceps is passed alongside the endoscope and visually directed samples can be obtained. With the help of the endoscope a visual assessment of the appearance of the endometrium can be performed at the same time. The collected tissue samples are fixed in formalin solution and send to the laboratory for staining and evaluati

4. Videoendoscopy

The hysteroscopy is a non-invasive and important diagnostic tool when performing a breeding soundness examination in a mare. A flexible endoscope will be introduced through the mare’s cervix and propelled forward through the uterine lumen. Under visual control the endoscope will be directed along both uterine horns and all the way up to the papilla of the uterotubal junction – the opening of the oviduct into the uterus. Valuable information about the colour, form and integrity of the cervix, the appearance of the endometrial mucosa and abnormal changes like endometrial lymphatic cysts, fluid accumulations, fibrous adhesions, foreign bodies, endometrial tumours and scarring are gathered via this technique. During hysteroscopy samples for cytological, microbiological and histological examinations can be obtained under visual control. The healthy endometrium is lined in longitudinal folds and circular ruggae, which is important for the active sperm transport to the uterotubal junction – the opening where the sperm enters the oviduct.

5. Ablation of endometrial cysts

Uterine cysts are fluid filled vesicles that can occur anywhere in the uterus, usually the project outward or away from the surface of the endometrium. It has been suggested that endometrial cysts reflect senility of the uterus and are commonly associated with mixed endometrial disorders. Both lymphatic and glandular cysts occur in the endometrium of the mare. Lymphatic cysts are most common and arise from obstructed lymphatic channels. Glandular cysts are a distension of uterine glands and caused by periglandular fibrosis. Depending on size, form, location and number of cysts they cause different problems. In mares with numerous clusters or multilobular cysts the transport of the spermatozoa might be mechanically blocked, in case of pregnancy – the mare may need several examinations before determination of a pregnancy by increasing vesicular size. The presence of numerous or large endometrial cysts can hinder mobility of the embryonic vesicle and restrict the ability of the early conceptus to prevent luteolysis, thereby blocking maternal recognition of pregnancy. Implantation of the embryo next to cysts can prevent absorption of nutrients and influence placentation by reducing the total area of placental exchange, resulting in early embryonic death, stillborn or weak foals being born. Various treatments have been proposed to eliminate endometrial cysts. The snare of the thermocautery instrument is inserted through the  working  channel the working channel of the videoendoscope, carefully pushed forward and looped around the cyst under visual control. The cyst will then be coagulated with the hot wire loop.

6. Hormone assays

Hormones control the oestrus cycle of the mare. A hormone is a chemical released by a cell, a gland, or an organ in one part of the body that affects cells in other parts of the organism. Many hormones can be measured (assayed) in the blood, to give an indication of metabolic processes and conditions, or “hormone imbalance”. This includes the reproductive hormones oestrogen, progesterone and othe