Equine Reproduction Articles & FAQs

– Horse Breeding Equine Reproduction Articles

Please Note: While we believe the information found on these pages to be accurate and up to date at the time of writing, it is provided here for informational purposes only, and is not intended to take the place of your veterinarian.

 

These equine reproduction articles are divided into “chapters”, each covering some different aspect of the horse breeding subject. The main menu is also divided to allow direct access to each section, providing a separate page for each, with the individual articles listed therein. The ISER XIII chapter contains a collection of summaries of papers which we consider to to be of immediate clinical relevance from the 13th International Symposium on Equine Reproduction, held in July 2023. We are adding to these summaries on a weekly basis.

ISER XIII

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...
Altrenogest Effect on Progesterone

Altrenogest Effect on Progesterone

Is it True Altrenogest Has an Effect on Progesterone Production? Pregnant and embryo recipient mares are often treated with supplemental progestins - commonly...
Badly Behaved Gelding

Badly Behaved Gelding

The Badly Behaved Gelding - Hormonally Driven or Not? "That is a badly behaved gelding - he must be 'proud cut'" or "I bet they left some testicular tissue in...
Blue Light

Blue Light

Does Maternal Exposure to Blue Light Affect Foal Development at Maturity? Because humans like to try and defy nature - January 1st being the "birthday" in...
Can Embryo Transfer Success Rates be Improved?

Can Embryo Transfer Success Rates be Improved?

Can Embryo Transfer Success Rates be Improved? Embryo transfer success rates are recognized as having a variable outcome dependent upon technician technique as...
Dead Sperm

Dead Sperm

Dead Sperm Do Not Cause Greater Uterine Immune Response! We know that sperm are the primary instigator for initiating the mare's post-breeding uterine inflammatory...
Diagnosis of Placentitis

Diagnosis of Placentitis

Diagnosis of Placentitis - Are Inflammatory Markers Useful? Placentitis is - literally and practically - "inflammation of the placenta" ("itis" as a suffix...
Endometrial Biopsy in the Mare

Endometrial Biopsy in the Mare

Endometrial Biopsy in the Mare - is one sample enough? An endometrial biopsy in the mare is a useful diagnostic to determine cellular health of the uterine lining...
Endometrial Cup Regression

Endometrial Cup Regression

Is it Possible to Cause Earlier Regression of the Endometrial Cups to Permit a Return to Breedable Estrus in the Mare? Unique to the early equine pregnancy...
Estimate Fetal Age

Estimate Fetal Age

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...
Frozen Semen for Standard IVF?

Frozen Semen for Standard IVF?

Frozen Semen for Standard IVF? In September of 2022, Felix et al. (University of Pennsylvania, New Bolton) published a paper which detailed the use of fresh...
Monitoring for EVA

Monitoring for EVA

Does Routine Monitoring for EVA Make a Difference? With the announcement this week of an outbreak of equine viral arteritis in PEI in Canada , a very reasonable...
N-acetylcysteine Improves Diagnostic Reliability

N-acetylcysteine Improves Diagnostic Reliability

Clean Culture and Cytology - Perhaps Not So Clean? For many years, the standard pre-breeding evaluation included a uterine swab culture alone. It was then determined...
Novel Treatment for Endometritis

Novel Treatment for Endometritis

Ozonated Sunflower Oil for Endometritis Treatment The overuse of antibiotics in medicine today - including equine reproduction - has led to searches for alternative...
Obese Mares

Obese Mares

Obese Mares Have More Problems Than We Thought! It has been previously documented that obese mares have a higher tendency towards early embryonic death, particularly...
Older Subfertile Mares

Older Subfertile Mares

Improve Pregnancy Rates in Older Subfertile Mares! How can one improve pregnancy rates in older subfertile mares? This category of mare is notorious for having...
Ovulatory Temperature Changes

Ovulatory Temperature Changes

Can Mare Temperature Changes Predict Ovulation? Temperature changes to predict ovulation are used in multiple species, including humans. The question has been...
Oxytocin Use to Support Pregnancy?

Oxytocin Use to Support Pregnancy?

Oxytocin Use to Support Pregnancy Instead of Regumate (Altrenogest)? It seems initially counter-intuitive to consider oxytocin use to support pregnancy instead...
Vitrification of Larger Embryos

Vitrification of Larger Embryos

Vitrification of Larger Embryos Successful vitrification of larger embryos - those >300µm - has typically not been achieved previously without use of the comparatively ...

Newer Articles

Newer FAQ's and Articles About Equine Reproduction - A selection of equine reproduction articles more recently presented on the website on a variety of topics...
Bacterial Infection of a Stallion's Reproductive Tract - Case Report

Bacterial Infection of a Stallion's Reproductive Tract - Case Report

Bacterial Infection of a Stallion's Reproductive Tract - A case report of the bacterial infection of a stallion's reproductive tract with images and outcome......
The Uterine Cytology Slide

The Uterine Cytology Slide

Preparing the Uterine Cytology Slide - Pre-breeding diagnostics should include the simple, rapid and easy-to-perform uterine cytology slide, which takes only about...

Professor John Newcombe, BVetMed, MRCVS

Professor John Newcombe, BVetMed, MRCVS - A collection of unpublished research work from this revered, prolific and eminent English equine reproduction researcher...

Backwards Foalings

Backwards Foalings

Backwards Foalings - reverse presentations of the foal - are rare but present particular difficulty. Potential for repetition is also present By Professor John...
Cessation of migration (fixation) of the embryonic vesicle

Cessation of migration (fixation) of the embryonic vesicle

Cessation of migration (fixation) of the embryonic vesicle - Is cessation of migration (fixation) of the embryonic vesicle inextricably linked to days 15-17 of...
Embryo Migration and Maternal Recognition

Embryo Migration and Maternal Recognition

Evidence that embryo migration (translocation) is not always if ever, necessary for the successful signalling or reception of the Maternal Recognition of Pregnancy...
Longer Last Cycle

Longer Last Cycle

The last completed cycle (IOI) of the year before a phase of extended winter anoestrus is significantly longer than the midsummer IOI in each mare By Professor...
Repeated Embryo Loss in Mares

Repeated Embryo Loss in Mares

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...
Seasonal absence of accessory ovulations

Seasonal absence of accessory ovulations

Seasonal absence of accessory ovulations in pregnant mares: What is the need for eCG? - Secondary ovulations or luteal developments support early pregnancy -...

Stallion Articles

A selection of equine reproduction articles related to stallion reproductive matters. Included are descriptors of breeding mount training, lab work, management and...
An Overview of Training the Stallion to Use the Breeding Mount

An Overview of Training the Stallion to Use the Breeding Mount

Phantom Training The Stallion - An Overview - A short description of phantom training the stallion in order to collect semen for AI, using the breeding mount....
Artificial Vagina - Comparisons and Reviews

Artificial Vagina - Comparisons and Reviews

The Artificial Vagina - 5 different commonly used types of equine artificial vagina compared - Colorado, Missouri, French (INRA), BotuPharma (Brazillian) and...
Assembling Your New INRA-AV and Preparing for Collection

Assembling Your New INRA-AV and Preparing for Collection

Putting together an INRA (French) AV (the Equine-Reproduction.com way) - A pictorial description of assembling the INRA (French) AV with the technique used...
Centrifugation - Tips, Techniques and Calculations

Centrifugation - Tips, Techniques and Calculations

Centrifugation of Stallion Semen - Tips and tricks for centrifugation of stallion semen, with a G-rate (RCF) calculator. Why centrifuge semen? See this article!...

Cryptorchid - Types and Determination

Cryptorchidism in the colt - This article describes the different forms, tests, resolutions and outcomes of cryptorchidism seen in the male horse (colt or stallion)....
FAQ's about Frozen-Semen

FAQ's about Frozen-Semen

Frozen Semen FAQs - New to using frozen semen? If you have questions, here we offer answers to some of those we hear relating to frozen equine (stallion) semen!...
FAQ's about the AI Process

FAQ's about the AI Process

Artificial Insemination and Transported Semen FAQs - Answers to some frequently asked questions about the equine A.I. (artificial insemination) and T.S. (transported...
Frozen Semen - part 1 of a 2-part article

Frozen Semen - part 1 of a 2-part article

Frozen semen preparation and use - An overview of frozen semen - Part 1 of a two-part article which appeared in the "Canadian Morgan" magazine in the November...
Frozen Semen - part 2 of a 2-part article

Frozen Semen - part 2 of a 2-part article

Frozen semen preparation and use - An overview of frozen semen - Part 2 of a two-part article which appeared in the "Canadian Morgan" magazine in the November...
Getting Set Up for Semen Collection

Getting Set Up for Semen Collection

Setting Up For Semen Collection and Transport - What laboratory and other equipment is required as a minimum to set up for stallion semen collection to ship cooled...
Ground Collection Techniques for the Stallion

Ground Collection Techniques for the Stallion

Ground Collecting a Stallion - A description of training a stallion for ground collection and a discussion of situations where ground collection would be beneficial....
How Clean is that Mare?

How Clean is that Mare?

Uterine Swabs, Smears and Cultures. - What should a stallion owner do to protect the Live Cover stallion from pathogenic transfer? An overview of swabs smears...
How Progressively Motile Are Those Sperm?

How Progressively Motile Are Those Sperm?

How Progressively Motile Are Those Sperm? - A comparison of videos of CASA evaluations showing poor, good and excellent progressively motile sperm. A useful teaching...

Manual Collection Techniques for the Stallion

A Modification of the Crump Manual Semen Collection Method as Used by the University of PA (New Bolton Center) - Description of semen collection from a stallion...
Phantom Plans - Build Your Own Breeding Mount!

Phantom Plans - Build Your Own Breeding Mount!

The Home-Built Power-pole Breeding Mount or "Phantom" - How to build a phantom mare (breeding mount) for collecting semen from stallions. Detailed plans for a...
The Cost of Doing Business - Setup Costs for Semen Collection

The Cost of Doing Business - Setup Costs for Semen Collection

The Cost of Doing Business (or "Why do I have to pay so much for collections when I breed my mare using transported semen?") - The cost of doing business when...

General Articles

General FAQ’s and Articles About Equine Reproduction - included are articles related to information about sexually transmissible diseases and exporting semen. ...
AI use in the TB industry

AI use in the TB industry

The question of AI use in the TB industry - a viewpoint - Here we offer some support for the use of AI and refute some of the common reasons often offered against...
Contagious Equine Metritis - CEM

Contagious Equine Metritis - CEM

Contagious Equine Metritis (CEM) - A notifiable disease, Contagious Equine Metritis poses a significant threat for domestic breeders and international trade....
Equine Viral Arteritis

Equine Viral Arteritis

Equine Viral Arteritis (EVA) - a detailed and descriptive article about equine viral arteritis (EVA), a disease which has severe negative reproductive implications....
Equine Viral Arteritis Factfile

Equine Viral Arteritis Factfile

Equine Viral Arteritis (EVA) - A summary of information about a disease with reproductive implications. This equine viral arteritis factfile shoots down some...
Frozen Equine Semen - An Overview

Frozen Equine Semen - An Overview

Frozen Equine Semen - An Overview - Some horse breeders are unsure about the use of frozen equine semen. In this overview, we offer some of the pros and cons....
Horse Breeding Ethics

Horse Breeding Ethics

The Ethics of Breeding - More than a popularity contest - This older article discussing horse breeding ethics, while written many years ago still holds true today...
Horse Lovers

Horse Lovers

And They Call Us Horse Lovers - Dr. Robert Miller explores the concept in more detail, with some surprising conclusions! By Robert M. Miller, DVM The Nation...
Mules - The First Cloned Equids

Mules - The First Cloned Equids

Cloned Mule Birth! First Successfully Cloned Equid - Our team was the first to break the news of the U-Idaho's first successfully cloned equid to the world...
Breeding Myth-Information - Items Commonly Heard!

Breeding Myth-Information - Items Commonly Heard!

Horse Breeding Myth-Information - Some commonly heard myths and errata about horse breeding (equine reproduction). Some funny, some frustrating - all incorrect!!...
Shipping Horse Semen to Canada from the US

Shipping Horse Semen to Canada from the US

Steps for Shipping Horse Semen to Canada from the US - A step-by-step guide to the USDA and CFIA requirements for Shipping Horse Semen to Canada from the US. By...

Mare Articles

Mare Articles About Equine Reproduction - A selection of articles related to mare reproductive matters. Included are descriptors of evalutions, lab work, management...
Abortion in the Mare - Some Pointers

Abortion in the Mare - Some Pointers

Late Term and Habitual Abortion in the Mare - Pregnancy loss in the mare is a constant source of concern among breeders. Here some common causes are discussed....
Anovulatory Hemorrhagic Follicles (AHF)

Anovulatory Hemorrhagic Follicles (AHF)

Persistent Anovulatory Follicles - Anovulatory Hemorrhagic Follicles, Luteinized Unruptured Follicles, PAFs, AHFs, LUFs - all follicular headaches in the mare!...
Artificial Insemination Method

Artificial Insemination Method

AI (Artificial Insemination) - Artificial Insemination of the Mare is not a difficult task to perform. Here we describe using an aseptic technique in detail....
Chromosome Translocation

Chromosome Translocation

Early Embryonic Loss and Genetics - Chromosomal translocations in horses may be a cause of early pregnancy loss or pregnancy failure. Dr. Teri Lear discusses the...
Cooled Transported Semen Breeding - Some Pointers

Cooled Transported Semen Breeding - Some Pointers

Breeding a Mare with Shipped Semen - Often perceived as going to be difficult, this can be a simple matter with some careful preparation, awareness and communication!...
Dealing with Retained Fetal Membranes (Placenta)

Dealing with Retained Fetal Membranes (Placenta)

Retained Fetal Membranes in the Mare - Post foaling retention of placenta and membranes. Noted reproductive vet Dr. Jon Pycock discusses at what point this becomes...
Dealing with the Older Maiden Mare Syndrome

Dealing with the Older Maiden Mare Syndrome

Breeding the Old Maiden Mare - Older maiden mares present problems of their own in achieving pregnancy. Noted reproductive expert Dr Jon Pycock explores some solutions....
Does My Mare Need Regumate?

Does My Mare Need Regumate?

Does My Mare Need RegumateTM ? - A perennial question for some is "Does My Mare Need Regumate?" Here we discuss some possible instances of need as well as the...
Double Trouble - The Twin Dilemma

Double Trouble - The Twin Dilemma

Managing Twinning in the Mare - While most equine pregnancies are simple, twinning when it happens is an issue. Here we discuss managing twinning in the mare....
Early Cyclicity

Early Cyclicity

Inducing Early Cyclicity in Mares - What practical solutions are there to start mares cycling earlier in the year? This article discusses some of the options....
Early Embryonic Death (EED) - what it is and why it may happen

Early Embryonic Death (EED) - what it is and why it may happen

Early Embryonic Death - Noted reproductive veterinarian Dr. Jon Pycock explores early embryonic death in the mare and some possible resolutions to the problem....
Early Equine Embryology

Early Equine Embryology

Embryology - Different Stages of the Early Equine Pregnancy - Equine embryology - early pregnancy images. A pictorial showing embryonic developmental images...
Failure of Passive Transfer

Failure of Passive Transfer

Failure of Passive Transfer in Neonatal Foals - low IgG - can lead to potentially fatal complications, but is easily managed in most with testing and supplementation...
Hormones of the Mare's Estrous Cycle

Hormones of the Mare's Estrous Cycle

The Mare's Estrous Cycle - an overview of the hormonal relationships that go to make up the reproductive cycle in the mare By Jos Mottershead (These charts...
How and Why to Delay Foal Heat

How and Why to Delay Foal Heat

Why delay foal heat? - Tips and techniques about how and why to delay first post-partum estrus ("foal heat") in order to improve pregnancy rates in the mare....
How to Thaw Frozen Semen to Breed the Mare

How to Thaw Frozen Semen to Breed the Mare

Thawing Frozen Semen and Preparing it for Artificial Insemination. - Techniques and methods related to handling and thawing frozen semen prior to breeding a mare....
Identifying, Treating and Breeding the "Dirty" Mare

Identifying, Treating and Breeding the "Dirty" Mare

The Dirty Mare - Noted reproductive veterinarian Dr. Jon Pycock discusses techniques and methods related to successfully managing and breeding the dirty mare....
Is my mare Overdue? The Perennial Panic!

Is my mare Overdue? The Perennial Panic!

Is my mare overdue? - A question frequently asked by concerned owners and discussed here with possible answers and statistics related to gestational durations....
Mare Management with Cooled-Shipped or Frozen Semen

Mare Management with Cooled-Shipped or Frozen Semen

Protocols for Mare Management with Cooled-Shipped or Frozen Semen - methods to time breeding of mares both with and without use of pharmacological manipulation....
Mare Ultrasound Pregnancy Images

Mare Ultrasound Pregnancy Images

Equine Ultrasound Pregnancy Images - Serial ultrasound images of early pregnancy in the mare. Discussion of variations and differences between stages seen in...
Most Common Ovarian Tumor

Most Common Ovarian Tumor

Granulosa Cell Tumor - Capable of affecting reproductive ability and overall disposition, the GCT is one of the most common ovarian tumors to be found in the mare....
Placentitis - Etiology, Diagnosis and Treatment

Placentitis - Etiology, Diagnosis and Treatment

Placentitis in the Mare - Diagnosis, Treatment and Outcome - A review of placentitis in the mare including current diagnostics and treatments. A case review is...
Predicting Foaling in the Mare

Predicting Foaling in the Mare

Simple Methods for Predicting Foaling - A description of some of the most reliable and simple methods of predicting foaling - as well as less reliable techniques!...
Predicting Ovulation

Predicting Ovulation

Indications of Impending Ovulation in the Mare - Predicting ovulation in the mare can be a challenge with mares displaying different characteristics. Here we describe...
Progesterone and Estradiol ("P&E") Hormonal Manipulation

Progesterone and Estradiol ("P&E") Hormonal Manipulation

Progesterone and Estradiol - when it comes to hormonal manipulation, nithing beats P&E! In many cases it allows pinpointing of ovulation to the day in mares....
Silent Heat in the Mare - Causes and Resolutions

Silent Heat in the Mare - Causes and Resolutions

Managing "Silent Heat" in the Mare - Silent heat (estrus) in the mare can be annoying at best and disastrous to a breeding program at worst. This article offers...
Steroidal Secretion Effects on Uterine Ultrasound Characteristics

Steroidal Secretion Effects on Uterine Ultrasound Characteristics

Ultrasound Characteristics of the Uterus in the Cycling Mare and their Correlation with Steroid Hormones and Timing of Ovulation - By Jonathan Pycock, BVetMed,...
Successful Breeding Takes More Than Chance

Successful Breeding Takes More Than Chance

Love me or love me not, but successful breeding takes more than chance - An older but updated article covering some of the more important items to consider for...
The Mare Reproductive Tract Dissected

The Mare Reproductive Tract Dissected

The Equine Uterus Dissected - Here we show the gross aspects of a mare reproductive tract dissected with labels and explanations. ...
The Oxytocin Protocol!

The Oxytocin Protocol!

Oxytocin use in the mare during breeding - Delayed Uterine Clearance and Breeding-Induced Endometritis problems can be helped by Oxytocin use when breeding a...
Timed Insemination Breeding

Timed Insemination Breeding

Timed Insemination Protocol for Frozen Semen Use - Use of frozen semen in the mare may be "labour intensive", but timed insemination can really simplify things!...
Ultrasound Examples of the Normal and Abnormal Ovulation

Ultrasound Examples of the Normal and Abnormal Ovulation

Ultrasound of the Normal and Abnormal Ovulation in the Mare - A video PowerPoint presentation with description and discussion showing ultrasounds of normal and...
Uterine Cytology Diagnostics in the Mare Explained

Uterine Cytology Diagnostics in the Mare Explained

Why Perform a Cytology Smear in Conjunction with a Uterine Culture? - The importance of uterine cytology evaluation supporting the culture results is explained....
Ventral Rupture in the Pregnant Mare

Ventral Rupture in the Pregnant Mare

Late Term Pregnancy Problems in the Mare - Ventral Rupture in the Mare - A late-term mare presents with ventral oedema and obvious discomfort. What is the diagnosis...
Vulval Conformation and Caslick's Procedure

Vulval Conformation and Caslick's Procedure

Vulval Conformation, Common Vulval Injuries and the Caslick's Procedure - Vulval Conformation and the Caslick's Procedure are important aspects to consider,...
Warming Semen in the Field

Warming Semen in the Field

Constructing An Emergency Slide Warmer - Sometimes lab equipment may not be available, so one has to become inventive. An emergency slide warmer is one such piece...
When is an Embryo not an Embryo?

When is an Embryo not an Embryo?

Equine Pregnancy Terminology - Conceptus? Embryo? Fetus? Abortion? Stillbirth? Premature? So many terms - a little light offered here in so much confusion! ...
When Progestin Therapy Doesn't Work

When Progestin Therapy Doesn't Work

I gave my mare Progesterone (or Altrenogest), but it didn't work! - an explanation of some of the causes of failure of promotion of estrus and other problems....
When to Breed a Mare

When to Breed a Mare

When Should You Breed Your Mare? Winter, Spring, Summer, Fall: consider the options - Seasonality can play a part in choosing the right time of year for your...
Where Do I Start? Pre-breeding Preparation

Where Do I Start? Pre-breeding Preparation

Breeding the mare - first steps - What are the first steps needed to increase success when breeding a mare? A review of possible pre-breeding evaluations and...
Why Prostaglandin Fails in Mares

Why Prostaglandin Fails in Mares

I Gave My Mare Prostaglandin, But It Didn't Work! - Commonly it's used in the mare to cause her to enter estrus, sometimes prostaglandin fails to cause estrus...
You're Ready to Breed Your Mare - But is the Semen OK?

You're Ready to Breed Your Mare - But is the Semen OK?

The Semen Looked Bad - Or Is It? Maybe not as bad as you think! A review of what constitutes a cooled semen dose, looking at some newer research and older dogma....

Videos

Video Articles About Equine Reproduction - A selection of our videos related to equine reproduction. Visit the page to see the wide variety of topics covered...