Welcome to The Select Breeders Blog

Breeding Strategies for Mares Inseminated with Frozen Semen

March 21, 2022

Timed artificial insemination (AI), programmed AI, one dose, two doses, deep horn insemination…what’s best for your mare?  With the increased use of frozen semen and the trend towards commodity sales (by the dose with no guarantee) veterinarians have developed a variety of strategies when managing mares being bred with frozen semen.  In this article, we discuss several options and which ones might be most appropriate for your situation.

Read More

Anti-sperm Antibodies: A Possible Source of Subfertility in Stallions

February 13, 2022

Every stallion owner’s worst nightmare: 2 months into the breeding season and your stallion is not settling his mares.  His bloodlines are impeccable, and he had a great start to his performance career so this year you offered to stand him at stud to outside mares, and the response has been great, 40 mares booked in his first season!  As a responsible and experienced stallion owner, you had a breeding soundness examination done and he passed with flying colors; good testicular size, good sperm production, good motility, concentration and morphology and his semen responded very well in a 48-hour cooled semen trial. He should be able to handle a book of 40 mares without problems.  So why isn't he settling his mares?

Read More

The Immunology of Endometritis, and the use of Immunomodulators to Improve Pregnancy Success

October 19, 2021

Inflammation and/or infection of the endometrium is the leading cause of subfertility in the horse, with persistent breeding-induced endometritis (PBIE) effecting approximately 10-15% of broodmares [1].  The deposition of spermatozoa, seminal plasma, and/or bacteria into the reproductive tract causes an inflammatory response, leading to an activation of the immune system.  This involves an activation of signaling molecules (cytokines), recruitment of immune cells (neutrophils), and eventual release of prostaglandin F2 alpha (PGF2a) from the inflamed endometrium, all of which lead to the eventual expulsion of excess fluid and contaminants [2-10].

Read More

Management of Twins in the Mare

April 20, 2021

The establishment and loss of twins, often results in a mare that is barren for a year and the associated economic loss.  The incidence of twin births has been documented as occurring in 1-2% of the equine population with twinning accounting for 6-30% of abortions in the mare. When twins are present, gestation proceeds normally until the conceptuses begin to compete for uterine space or placenta.  With or without mummification, death of one fetus leads to abortion, usually between 5 and 9 months of gestation. Lactation commonly occurs after one foal dies and causes premature mammary gland development.  Surviving foals are usually weaker, more susceptible to infection, and slower to develop than singletons. Fortunately, with the use of ultrasound and an increased understanding of the mechanisms involved in twinning, better approaches to twin reduction have been developed.

Read More

Care and Vaccination of the Pregnant Mare

February 05, 2021

Now that your mare is safely checked in foal, the next step in the journey begins. It is time to plan ahead for the care and management of your pregnant mare and for welcoming the arrival of your foal. A major first step is, where will your mare foal out? If she is to foal out at home it is assumed you have a suitable foaling stall, a pasture with shelter and safe fencing to house the mare and her foal. Research and start to compile your foaling kit, emergency plans and contacts, secure a source of colostrum and research options for nurse mares. Of course, we all hope for a normal, successful delivery, but we have to be prepared for worst case scenarios. If the unexpected happens at such an emotional time, having a plan in place will alleviate stress and save time when tough decisions must be made. If your mare will foal out at another facility, plan on moving her 20-30 days prior to foaling so she can build up immunity to her new local environment.

Read More

The Sperm Mitochondrion: Organelle of Many Functions

January 10, 2021

The sperm mitochondrion (pictured left) is one of the most damaged organelles during cryopreservation and is likely responsible for the majority of loss in motility and fertility after a freeze-thaw cycle. Our laboratory at UC Davis has focused on developing an increased understanding of mitochondrial bioenergetics in sperm that could provide strong rationale for marked improvement in preservation and assisted reproduction techniques.

Read More

Use of Ultrasonography for Pregnancy Diagnosis in the Horse

December 14, 2020

Early detection of pregnancy in mares is strongly demanded by owners in order to maximize breeding efficiency and economic investment. The most reliable and earliest available tool for conceptus detection is ultrasonography. Other diagnostics include palpation per rectum and hormonal blood tests (i.e. estrone sulfate in serum or urine; equine chorionic gonadotropin in serum) as these methods are useful when examination by ultrasound (per rectum or transabdominally) is not possible or feasible.

Read More

Genetic Preservation in Mares Utilizing TVA and ICSI

October 20, 2020

Early demise due to illness or injury can shorten a mare’s reproductive career. Additionally, subfertility can also have a negative impact on a mare’s ability to produce a foal. There have been a multitude of advances in the past 20 years that have allowed for the preservation of genetics in mares. Techniques such as transvaginal ultrasound-guided oocyte aspiration (TVA) and intracytoplasmic sperm injection (ICSI) have allowed us to produce embryos in vitro, circumvent subfertility in mares, and preserve genetics from mares that have died.

Read More

Establishing a Foal’s Healthy Gut Microbiome

April 20, 2020

The mare-foal bond is a special connection that’s normally associated with the behavioral interactions between a mare and her foal. What’s not usually thought of is the bond formed between their immune systems and microbiomes. A healthy gut microbiome goes hand in hand with a strong immune system. Foals have innate immunity at birth, but several adaptive immune responses can take up to a year to develop to those of an adult horse. The correct development of a foal’s immune system is very important in protecting them from microbial pathogens and, in turn, gastrointestinal disease.

Read More

Breeding Soundness Exam of the Mare

February 19, 2020

To evaluate a mare's potential for reproductive success or failure, veterinarians often perform a "breeding soundness examination" (BSE). As the breeding season approaches, many owners may opt for a pre-breeding BSE to identify and address any potential reproductive issues prior to breeding. This examination is invaluable for estimating the likelihood of a mare successfully conceiving, carrying a pregnancy to term, and delivering a healthy foal. Pre-breeding examinations are usually performed early in the breeding season when the mare has just begun to cycle or, at the very least, is not in anestrus. Furthermore, the BSE provides veterinarians and owners with important information to determine whether a particular mare should carry a foal herself or whether she might better serve as an embryo or oocyte donor, as well as what breeding strategies are most appropriate for the individual mare.

Read More