The vet is usually consulted at several stages of the breeding programme, for example:
- gynaecological examinations during oestrus
- pregnancy diagnosis and regular checks throughout gestation
- pre-foaling vaccination
- post-foaling checks
The purpose of the examination is to assess any problems that could affect the mare’s ability to conceive or carry the foal to full term. Ideally the checks should be made early in the season so any problems can be detected and treated.
The vet will requested the following information:
- previous breeding history
- previous foaling history
- health problems such as lameness, colic, cushings
- vaccination and worming status
- body condition
- visual inspection and assessment of the vulva, vagina and cervix
- rectal palpation and ultrasonographic examination of the uterus and ovaries. Ultrasonographic examinations can reveal the presence of abnormal amounts of fluid within the uterus and endometrial cysts, which can be mistaken for an embryo if not identified pre-breeding
- collecting swabs for CEM culture / PCR from the clitorus
- performing an endometrial swab for culture and cytology
If purpose-built stocks are not available the mare should be examined in a stable. She must be adequately restrained by a competent handler and it is helpful if her tail is bandaged. The vet will require:
- a bucket of clean, warm water
- an assistant to hold the tail out of the way
- a power supply for the scanner
Sometimes it is necessary to apply a twitch or sedate the mare for the examination.
Assessment of the vulva
The vulva is checked for any signs of discharge. The vulval lips should be almost vertical and meet together in the midline, forming a firm seal. If the vulva slopes forwards, the seal is easily broken and air may be sucked into the vagina as the mare moves. Aspiration of air and contamination by faeces can lead to inflammation of the vagina, cervix and the lining of the uterus with resultant infertility.
If the vulval conformation is poor, a Caslick’s operation may be carried out. This involves suturing the upper part of the vulval lips together under local anaesthetic. This must then be opened before the mare foals or she will tear during foaling. Ideally this should be done by the vet 1 – 2 weeks prior to foaling.
Treatment of endometritis
When laboratory results show a mare is suffering from endometritis, she is likely to be treated with infusions of sterile saline and antibiotics into the uterus for a period of 3 – 5 days. A mare with endometritis will have reduced conception rates or may suffer from early embryonic loss, so it is important to identify and treat these mares before covering.
A second swab and smear must be taken early in the following oestrus. If the treatment has been successful and there is no evidence of endometritis, the mare can be covered / inseminated.
If the mare fails to conceive, or the swabs and smears reveal persistent or recurrent infection or inflammation, an endometrial biopsy may be taken. This can be done at any stage of the cycle but is easiest during oestrus.
Biopsy forceps are passed through the cervix and a small piece of endometrium is removed and sent to a laboratory for histology (examination of the tissue under the microscope). This reveals the extent of any inflammatory or degenerative changes in the endometrium. Treatment can then be recommended and a prognosis for successful breeding given. A second biopsy is taken approximately one month later to assess the results of treatment.
Examination of the endometrium with an endoscope can provide the vet with valuable information such as the presence of cysts and damage sustained during previous pregnancies. The normal endometrium is smooth and pink in appearance. An inflamed endometrium may appear very haemorrhagic and have adhesions which obstruct the passage of the endoscope. Occasionally foreign bodies can be found using this procedure.