Category Archives: pregnancy

Repeated Embryo Loss in Mares

Posted: | June 2, 2024

Repeated Embryo Loss in Mares is the Result of Retarded, Small for Age, Embryonic Vesicles. By Professor John Newcombe, BVetMed, MRCVS A Normal Foetus and then a Foal Will Eventually Result When a Normal Embryo is Produced: A Case Report ABSTRACT A twelve-year-old maiden/barren part-TB mare with otherwise limited reproductive history, was sent to an equine fertility clinic… Read More »

Diagnosis of Placentitis

Posted: | November 19, 2023

Diagnosis of Placentitis – Are Inflammatory Markers Useful? Placentitis is – literally and practically – “inflammation of the placenta” (“itis” as a suffix indicates inflammation). Use of assays for inflammatory markers in the mare – in particular Serum Amyloid A (SAA) – have been previously suggested as possible diagnostic tools for use in the identification of placentitis. Inflammatory… Read More »

Estimate Fetal Age

Posted: | October 15, 2023

A New Method to Estimate Fetal Age in the Mare Sometimes there arises a need to estimate fetal age in the mare, for which a breeding date perhaps is unknown. Several methods have been previously identified, such as measurement of the fetal eye[1][2], or biparietal diameter, eye approximated volume, fetal aortic diameter and femur length[3], among others. These… Read More »

Altrenogest Effect on Progesterone

Posted: | October 7, 2023

Is it True Altrenogest Has an Effect on Progesterone Production? Pregnant and embryo recipient mares are often treated with supplemental progestins – commonly Altrenogest in the oral form Regumate, or injectable in one of several longer-acting commercial preparations – in an expectation of “low progesterone” levels. There is a significant question as to what number should be applied… Read More »

Oxytocin Use to Support Pregnancy?

Posted: | September 9, 2023

Oxytocin Use to Support Pregnancy Instead of Regumate (Altrenogest)? It seems initially counter-intuitive to consider oxytocin use to support pregnancy instead of Regumate or other altrenogest treatments which are commonly used to potentially increase – or at least maintain – progestin levels during early pregnancy in the mare. Oxytocin causes uterine contractions and will expel the pregnancy, right?… Read More »


Posted: | August 6, 2023

ISER XIII “Snippets” – Held in Brazil in August 2023, ISER XIII produced a variety of useful research with immediate clinical value, here we review some of the presentations The thirteenth International Symposium on Equine Reproduction (ISER XIII) was held in Foz do Iguaçu, Brazil between July 10th–14th, 2023. Around 400 veterinarians, researchers and animal scientists were present,… Read More »

Cessation of migration (fixation) of the embryonic vesicle

Posted: | July 23, 2023

Cessation of migration (fixation) of the embryonic vesicle – Is cessation of migration (fixation) of the embryonic vesicle inextricably linked to days 15-17 of pregnancy? By Professor John Newcombe, BVetMed, MRCVS Is cessation of migration (fixation) of the embryonic vesicle inextricably linked to days 15-17 of pregnancy? Introduction The ability of the embryo to signal to the endometrium… Read More »

Words To Lose!

Posted: | April 15, 2023

When lecturing on equine reproduction our lead lecturer Jos Mottershead often comments that there are several words to lose in order to avoid confusion and – plainly – being incorrect. The words he always cites are “never” and “always”, because the moment that one uses those words, invariably someone in the audience comes up with a situation which… Read More »

Seasonal absence of accessory ovulations

Posted: | February 8, 2023

Seasonal absence of accessory ovulations in pregnant mares: What is the need for eCG? – Secondary ovulations or luteal developments support early pregnancy – but what if there is a seasonal absence of accessory ovulations? By John R Newcombe, Equine Fertility Clinic, Warren House Farm, UK Introduction Years before the use of diagnostic ultrasound, WE Allen noticed that secondary… Read More »

Embryo Migration and Maternal Recognition

Posted: | September 18, 2022

Evidence that embryo migration (translocation) is not always if ever, necessary for the successful signalling or reception of the Maternal Recognition of Pregnancy (MRP) in the mare – Long thought to be connected, embryo migration and maternal recognition may not be so closely related after all. By Professor John Newcombe, BVetMed, MRCVS A Case Study By tracking the… Read More »