‘Problem’ mare not easy to get in foal

Een probleemmerrie wordt niet drachtig binnen drie hengstigheden (Foto: Pietje Boel)

June 15, 2021

A problem mare is defined as not being pregnant after three heats (Photo: Pietje Boel)
Veterinarian Karin Hendriks specialises in the latest, modern reproduction techniques in horses. The stud season is already pretty advanced and most broodmares are pregnant again. There are however, mares that are still not pregnant after three cycles in spite of good care and good-quality semen. Hendriks: ‘We then speak of a ‘problem’ mare.’


Karin Hendriks found herself a challenge when she was presented with a 10-year-old mare that had not become pregnant for quite a while already. Hendriks examined the mare: ‘Rectal and radiographic examination showed the mare to be in the early stage of heat, but also showed up too much cloudy fluid in the uterus. This pointed in the direction of an infection.’ There can be multiple reasons for an infection by bacteria, yeasts and fungi in the uterus, for example because of ‘air-sucking‘ through the vulva, unhygienic conditions during insemination, contaminated semen or a poor immune system of the uterus.

Mucus sample

An infection can be diagnosed by taking a mucus sample from the uterus when the mare is in heat. The next day a preliminary result showed many inflammatory cells in the cytology (smear/swab) and the presence of a bacterium (beta-hemolytic streptococcus). ‘This is a very common infection which responds well to treatment of the uterus with antibiotics,’ Hendriks explains.


Hendriks confirmed that the mare was still in heat. ‘The uterus was treated by inserting antibiotics into the uterus on three successive days. On the third day of treatment it became apparent that the mare had ovulated and she was allowed to go home until the next heat. Two and a half weeks later she returned for a check-up and the newly-taken mucus sample turned out to be ‘clean’, so free from bacteria. During this heat she was inseminated and sixteen days after the ovulation she proved to be pregnant.’

Inflammatory cells cytology (smear)

Read the full on-the-job article about ‘problem’ mares by Dr Karin Hendriks in the July issue of Phryso.





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