SEEING DOUBLE: Twin reduction, management and results
Peter C. Sheerin, DVM, Dipl. ACT

 With breeding season fast approaching, I’ve been given the opportunity to discuss one of the common reproductive procedures performed on mares: twin reduction.  Twins are a common occurrence in our practice as the majority of mares we see are Thoroughbreds.  The breeds most often associated with twins are Thoroughbreds, Draft horses and Warmbloods.   Horses crossed with these breeds also have an increased likelihood of having twins.  At one time, twins were the leading cause of non-infectious abortion in the mare.  With the common use of ultrasound in pregnancy detection, that is no longer the case.
In the horse, the embryo moves around in the uterus until 17 days after ovulation.  This is to allow pregnancy recognition to occur.  The embryo secretes a substance that tells the mare she is pregnant and should not come back in heat.  This mobile phase is the best time to reduce twins.  If the mare is examined early enough, (14 to 15 days after ovulation), one can come back and re-examine the mare later in the day or the next day if the twins are in a position where reduction would be difficult.  Additionally, one of the techniques involves moving the embryo to the tip of the uterine horn prior to reduction.  This would not be possible if the embryo has stopped moving.
We typically examine the mares for pregnancy 14 or 15 days after ovulation.  If twins are detected at that point, an attempt will be made to reduce one of the twins.  Prior to or just after the procedure, the mares will be treated with an anti-inflammatory drug (most often Banamine®) and a form of progesterone (most often injectable progesterone).  The mares will be maintained on a progestin (Regumate® or injectable progesterone) for a period of time after the reduction.
We recently performed a retrospective research study looking at twin reductions and the subsequent live foal rates.  We looked at all the mares who had twins reduced in 2003, 2006, 2007 and 2008.  We also created a list of control mares.  The control mares were mares from the same farm, bred in the same year and had singleton pregnancies.  There were 1493 twinning mares and 1378 control mares.  We wanted to determine if the live foal rates were different in mares that had twins reduced and mares that carried a singleton pregnancy.  We also wanted to know if the age of the mare caused any differences in live foal rates.  Additionally, we evaluated the treatments used at the time of twin reduction.
We found that mares that had twins reduced had a lower live foal rate than mares carrying a singleton pregnancy.  Eighty percent of the mares that had twins reduced had a live foal while 87% of the singleton mares did.  We also found that the older the mare was, the more likely she was to lose her pregnancy.  This happened in both groups.  Mares that were older than 15 and had twins reduced had a lower live foal rate than younger mares (66.2 vs. 83.2).  In the singleton pregnancies, a similar trend was noted (77.6% vs. 89%).
If a mare had a significant health issue during pregnancy such as colic surgery, medical colic requiring hospitalization, significant podiatry issue or other issues, she was less likely to have a live foal.  Sixty percent of both the mares with twins reduced and singleton pregnancies that had other health issues had live foals.  The healthy mares in each group had greater than 80% live foal rate.
We also examined the treatments given at the time of twin reduction.  The most common treatment was Banamine® and injectable progesterone.  Sixty seven percent of the mares received this treatment.  Mares treated this way had a higher live foal rate than mares treated with any of the other treatments.  Eighty five percent of mares given this treatment had live foals as compared to mares given other treatments where eighty two percent of mares had live foals.  Mares that did not receive any treatment had a live foal rate of 77 percent.  Finally, we determined that the pregnancy loss rate was similar if twin reduction occurred on 13 to 20 days after ovulation.  The number of mares where twins were reduced after 18 days was small and we did not evaluate location of the twins.
Another study was performed using the results of one individual veterinarian.  This study looked at the location of the twins at the time of reduction and the live foal rates.  We were curious as to whether twins that were side by side at the time of reduction were more or less likely to have a live foal than mares where the pregnancies were separated.
There was no statistical difference between adjacent and non-adjacent embryos with respect to pregnancy loss after twin reduction.  This study also supported the negative effect of age on live foal rate.
So what does all this mean to mare owners?  Twins can be successfully reduced between day 13 and 18 post ovulation.  There will be a slightly higher pregnancy loss in mares that have twins reduced when compared to mares carrying a singleton pregnancy.  If the twins are side by side (shown in 12 day ultrasound at right) or separated from each other, the pregnancy loss rate will be similar before 18 days of pregnancy.  We don’t know about later than this because there were not enough of these mares. Older mares have a higher rate of pregnancy loss.  This age effect is more pronounced in mares where twins were reduced.  If the mare has a significant health issue during pregnancy, she will have a higher pregnancy loss rate than a mare that was healthy during her pregnancy.  Finally, treating the mares with anti-inflammatories and a progestin at the time of twin reduction will give you a higher live foal rate than no treatment.

Exploring antibiotic associated diarrhea in 3 large practices

Antibiotics are commonly used in veterinary medicine to treat a number of infectious diseases.  There are many different types of antibiotics, each targeting different pathogens and having different side effects.  Dr. Bonnie Barr, VMD, DACVIM, along with internal medicine clinicians at two large equine referral practices in Florida and New Jersey, studied the association between antibiotic administration on the farm for non-diarrheic cases and the prevalence of diarrhea.  The particular antibiotics associated with these cases were identified as well as any pathogens found.   The results were presented at the 2010 AAEP convention in Baltimore, MD and Pfizer Animal Health provided the funds to enable this research project.

Dr. Barr’s study evaluated 5251 horses that were treated with various antibiotics on the farm for non-gastrointestinal problems during 2009.  Only 32 of these horses developed diarrhea, which is a prevalence of 0.6%.  The most common antibiotics used were: oxytetracycline, trimethoprim-sulfa (TMS/SMZ), gentamicin, penicillin and doxycycline.  These antibiotics all had less than 1% incidence of causing diarrhea.  The highest occurrence was seen with enrofloxacin (Baytril®), 5.4%, and the combination of penicillin/gentamicin, 3.2%.  Out of those 32 horses, 6 died or were euthanized (18.8%). 

Infectious pathogens were identified in 7 of the 32 cases, an incidence of 22%. Clostridium difficile was identified in fecal samples from 4 horses, and Salmonella in samples from 3 horses.  Clostridium difficile was found in 2 of the 6 horses that died.  No other pathogens were found in the remaining 25 horses.

While this study found the risk for antibiotic associated diarrhea to be very low (0.6%), it emphasizes that antibiotics should be used only when necessary. 

Tooth Root Abscess
R. Brad Tanner, DVM
Tooth root infection in the horse is a relatively common disorder occurring primarily in the cheek teeth.  Upper and lower cheek teeth have been reported to become infected at similar rates.  The terms tooth root abscess and tooth root infection are synonymous, though a more accurate term is apical infection.  Apical refers to the tooth root area and surrounding tissue.  The cheek tooth of a horse is very long and often the apical infection includes not only the tooth but also the periodontal ligament, surrounding bone and potentially sinuses.  The reported median age of horses with cheek teeth infections is 5-7 years but these infections can occur at any age. 
Causes of apical infections are numerous including fractures, developmental disorders, blood borne pathogens, etc.  Fractures may be large sagittal (center of the tooth lengthwise) fractures from traumatic incidences or small fissure (deep narrow crack in the tooth) fractures that are not clinically seen until extracted.  Developmental disorders include too numerous cheek teeth, which creates overcrowding and can lead to incomplete eruption or impaction of cheek teeth.  Also, too few cheek teeth can leave gaps between teeth and increase the chance of periodontal disease.  Periodontal disease begins at the gum level surrounding the tooth.  Perhaps the most common cause of apical infections is the spread of bacteria in the blood.  The horse has a tremendous blood supply to erupting teeth (eruption bumps) and may explain why we see more of these infections in young horses that have rapidly developing tooth roots.
Infections are often suspected by owners prior to an examination.  Horse owners may notice a malodorous discharge from the nose or jaw that is not always present.  It may be accompanied by a head tilt or decreased appetite but often is not.  Another complaint of owners is that one side of the jaw is much more swollen than the other.  With these suspicious clinical signs, a thorough oral exam with mouth speculum is warranted to determine if there is a problem with a cheek tooth.  This examination should include a dental mirror and probe to evaluate the grinding surface of any tooth that is suspected of infection.  Oral exam alone is often not enough.  Radiographs of the suspicious area are the best way to determine if an infection is present. (Radiograph above left shows infected tooth root area with a draining tract)
Dental extraction of the infected tooth is most often the necessary treatment for an apical infection.  These infected cheek teeth can be extracted orally with few complications if the exposed crown of the tooth is large enough to be grasped and if the tooth does not have a fracture below the gum level.  The care of a horse after cheek tooth extraction is relatively simple if there is no sinus involvement with the infection.  The empty tooth socket is filled with antibiotic and a plug is made with dental impression material to fill the hole created by the missing tooth.  The plug is removed in two weeks and the horse re-evaluated.  Long term after care includes routine biannual floating to assure that the opposing tooth does not grow to form a step defect.  In young horses the adjacent cheek teeth will slowly migrate to eventually fill the void left by the missing tooth.
Dentistry is an important part of the overall health and well being of the horse.  Routine dental re-equilibration (floating) performed by a knowledgeable and experienced practitioner can alleviate pain and prevent many dental disorders.  It is recommended that adult horses have their teeth “floated” once per year and that horses younger than 5 years of age have teeth “floated” twice per year.  In younger horses it is important to evaluate the development of permanent teeth as well as the shedding of immature teeth (caps). Geriatric horses have their own special needs and should be evaluated annually or more often if colic, choke or other medical concerns arise.

 Rood & Riddle to Host Equine Dentistry Clinic

Rood & Riddle Equine Hospital will host an equine dentistry clinic from 8am to 4pm January 29 in the Rood & Riddle Podiatry building. Horse owners are invited to schedule an appointment for their horse or horses to have an oral exam by Dr. Brad Tanner at no charge. After the examination, any recommended procedures will be explained and discussed with owner, and performed only with the owner’s permission. Each appointment will provide adequate time to complete routine dental floating or other minor procedures. If more extensive dental work is required, it will be scheduled for another time. Payment is required at the time of service for routine dental floating or any other procedures performed during the clinic. Owners participating in the Dentistry Clinic will receive discount coupons on purchases from Rood & Riddle Veterinary Pharmacy.
Advanced dentistry techniques have become a primary focus in Dr. Tanner’s practice since joining Rood & Riddle in 2005. Through continuing education, he regularly adds to his knowledge base, and expands dentistry services at Rood & Riddle.  With the use of modern power instruments he is able to correct numerous abnormalities and perform routine procedures providing short, pain free experiences for the horse.  Dr. Tanner's interest in performance horses greatly influenced his focus in dentistry.  Head carriage and poll flexion are important in multiple sport horse disciplines and cannot be achieved without an equilibrated mouth. 
After addressing their horse’s oral health, owners will also have the opportunity to discuss nutritional needs of their horse.  Alltech will be in attendance with information and free samples of LIFEFORCE™, a natural, scientifically proven supplement that promotes overall digestive health, supports immune function, and optimizes performance. Representatives from Hallway Feeds will also be on hand with samples and for nutritional consultation to customize your feeding program.

Rood & Riddle will also have on display DIA (Diagnostic Imaging Atlas) educational software which illustrates with 3-D animation the anatomy of the horse’s mouth and dental structure.  Don’t miss this opportunity to take care of your horse's annual exam and learn more about equine dental health. Oral exams at the Equine Dentistry Clinic are by appointment only and must be scheduled by Thursday, January 27. To schedule your appointment or receive additional information, please phone Charlotte Chilton at (859) 233-0371 or contact by e-mail to  

Rood & Riddle Surgery - Let our experience work for you
A fundamental truth – past experience is a good predictor of future results

From the very beginning, Rood & Riddle Equine Hospital has been driven to provide the best equine medical care available and to continually strive for new solutions for both old and new problems in equine health. Since opening in 1986, the Rood & Riddle Surgery Department has exemplified excellence and assembled a team of 5 surgeons considered leaders in their field. The facility has also kept pace with advancing technologies and has expanded to offer 5 operating rooms, 9 recovery stalls, with 74 stalls available for hospitalized surgical cases and 35 stalls strictly reserved for outpatient procedures. Additionally, the facility is the only one in Kentucky and surrounding states to have nuclear scintigraphy, high speed treadmill, high field MRI and stem cell laboratory capabilities on the same campus, enabling clinicians to provide state of the art diagnosis and therapy at a single site.

All 5 of the Rood & Riddle surgeons completed rigorous residency programs at universities well known for their equine surgical training programs and are board certified by the American College of Veterinary Surgeons. Collectively, they have performed over 40,000 elective and emergency surgical procedures over the last 10 years. They have been on the forefront of equine surgical innovation including arthroscopic, limb corrective surgery, simple and complex fracture fixation, arthrodesis techniques, and innovations in equine upper respiratory surgery as well as abdominal and reproductive procedures. 

The Rood & Riddle surgeons have comprehensive experience with all types of elective orthopedic and soft tissue procedures. Although Lexington is best known as a center for Thoroughbred racehorses, our surgeons have experience with all breeds and disciplines, and are knowledgeable of the unique needs of each breed or discipline from the early developmental needs of foals to the athlete in training.

In addition to elective surgery expertise, our surgeons have extensive experience with emergency disorders of the abdomen, upper airway, reproductive and musculoskeletal systems, admitting approximately 700 surgical emergency patients annually. At the time of admission, each patient is evaluated by an experienced surgeon and supporting staff. This enables immediate surgical attention if needed. This approach to emergency care produces the best possible outcomes.

The clinical successes of the Rood & Riddle surgeons have reached far beyond the 24 acre campus in Lexington, Kentucky. Rood & Riddle surgeons are recognized by their peers as experts in equine surgery and are sought after to give multiple scientific presentations at national and international continuing education meetings each year. Collectively, they have published over 140 articles and 40 book chapters in equine surgery and are leaders in professional organizations such as the American College of Veterinary Surgeons, American Association of Equine Practitioners and Association for the Study of Internal Fixation (Fracture Repair).  The Rood & Riddle surgeons also annually lead courses which train current and future equine surgeons in techniques of upper airway surgery and fracture repair in the horse. The Rood & Riddle surgeons recognize the best way to improve themselves, the veterinary profession and your horse’s care is through their involvement with professional equine associations. They are fully committed to professional service and to the advancement of equine surgery.  
The success of the Rood & Riddle surgery department is not based on individual effort. The surgeons are supported by an experienced group of technicians, administrative assistants and other support staff dedicated to give each horse the best care and each client the best service possible. In addition to support staff, the surgeons consult when needed with the other Rood & Riddle clinicians who are also recognized as experts and leaders in their fields in internal medicine, neurology, neonatology, cardiology, ophthalmology, reproduction and podiatry, to provide complete medical care for each patient.
The Surgery Department at Rood and Riddle Equine Hospital is dedicated to provide compassionate, high quality, state of the art diagnostic and surgical treatment of your horse on either an elective or emergency basis.  The facility and staff is designed to fill all your needs in a professional, efficient and timely manner. Each surgeon’s goal is to have optimal patient outcomes with good value for you and your horse. They recognize that the only measuring stick is your success and put the full measure of their education, training and experience into each and every patient.  
The Rood & Riddle surgery team of  Larry R. Bramlage, DVM, MS, Dipl. ACVS, Rolf M. Embertson, DVM, Dipl. ACVS, Scott A. Hopper, DVM, MS, Dipl. ACVS, Alan J. Ruggles, DVM, Dipl. ACVS, and J. Brett Woodie, DVM, MS, Dipl. ACVS, are ready to put their experience and skill to work for you. Please call us today to discuss how we can meet and resolve your equine surgical needs at (859) 233-0371 or contact us on through our Admissions and Appointments page.  

 Bramlage honored for contributions to equine orthopedic surgery

The American College of Veterinary Surgeons Foundation recently awarded Dr. Larry Bramlage the 2010 ACVS Foundation Legends Award for his dedication and contributions to the field of equine orthopedic surgery. The annual award recognizes ACVS Diplomates who have developed a surgical or diagnostic procedure of significant value, proven by becoming the treatment or test of choice for a given condition.

Over the span of his 30 year career, Dr. Bramlage has been influential in advancing the art and science of fracture repair. He is perhaps most well-known for developing the fetlock arthrodesis, a lifesaving procedure for severe fetlock injuries that fuses and stabilizes the joint. The technique is now the classic procedure used by most equine orthopedic surgeons for fetlock arthrodesis. Dr. Bramlage has also been a pioneer of equine arthroscopic surgery and a leader in equine lameness diagnostics.

In addition to clinical practice, Dr. Bramlage has authored or co-authored over 70 publications in referred journals, written numerous book chapters, and speaks at numerous professional meetings every year. He is a past president of the American Association of Equine Practitioners and the ACVS, served 12 years as chair of the Research Advisory Committee of the Grayson Jockey Club Research Foundation, and continues to serve on its Board of Directors. Dr. Bramlage also serves as the media liaison for the AAEP’s On Call program where experts are immediately available to the media during many televised races, including the Triple Crown and Breeders’ Cup.  

Rood & Riddle acquires new digital radiography technology

Rood & Riddle Equine Hospital recently acquired a new state of the art digital radiography (DR) panel manufactured by Canon that will allow imaging of skeletal areas that were previously difficult to assess radiographically. Using the wireless panel with a powerful generator, Rood & Riddle is now able to image the entire equine spine, including the thoracolumbar region, an area that historically veterinarians have been unable to image well.  Additionally, the new panel gives us the ability to obtain high-quality radiographs of the pelvic region in some standing horses without the risk of general anesthesia. Previously, patients required anesthesia to obtain diagnostic-quality pelvic images.
“The capabilities of this panel are truly amazing,” reports Dr. Katie Garrett, the director of diagnostic imaging at Rood & Riddle.  “It gives us absolutely beautiful images. “
The CXDI-70C Canon panel was introduced for human use in late 2010. Rood & Riddle Equine Hospital is the first site of veterinary application of this panel.

Annual Rood & Riddle Education Seminar

Rood & Riddle Equine Hospital’s annual client education seminar is scheduled for February 3, 2011, at the Embassy Suites in Lexington, Kentucky. Clients are invited to join us at 6:30pm for refreshments, with educational presentations from 7:00p-8:30pm.
The featured presentations are:
The Current State of Equine Stem Cell Therapy
            Dr. Scott Hopper will discuss ongoing research and progress in equine regenerative medicine
Inside Equine Dystocia-Solutions and Decisions
            Using 3-D animation, Dr. Brett Woodie will illustrate the complexities of fetal position during parturition, and discuss corrective measures and emergency protocols for dystocia
Is This Horse Lame or Neurologic?
            Internal Medicine Specialist Dr. Steve Reed will present 2 hospital cases and explain the subtle signs that differentiate symptoms as lameness or neurologic signs. Orthopedic surgeon, Dr. Larry Bramlage will contribute commentary for discussion.

RSVP is not required for attendance but requested so that we may properly plan for adequate seating and refreshments. If you plan to attend, please RSVP by February 1, to or by phone to (859) 233-0371. We look forward to hosting you at this informative meeting.  

Around the Practice . . .

In 2011 Rood & Riddle Equine Hospital celebrates the 25thanniversary of the hospital opening. Since the facility opened in 1986, it has grown andexpanded with the advancements of equine veterinary medicine adding new technologies and services throughout the years. The veterinarians and staff of Rood & Riddle are thankful for the support of their clients, new and old, and are honored by all who entrust their horses to our care. We look forward to serving the equine community for the next 25 years.

Dr. Deborah Spike-Pierce was recently named the 2011 vice president for the Kentucky Veterinary Medical Association. She will serve a one-year term. The KVMA serves Kentucky veterinarians by acting to promote, protect and improve the veterinary profession. The organization cooperates with government officials and inter-professional medical, agricultural and conservation organizations in obtaining the enactment and enforcement of laws in Kentucky designed to protect the public health and the health and well-being of all animals including pets, poultry and wildlife.

Rood & Riddle veterinarians were busy during the annual convention of the American Association of Equine Practitioners (AAEP) held in December in Baltimore, Maryland. Speakers and topics included Dr. Johanna Reimer who presented lectures on techniques to maximize sonographic image quality when evaluating the hind proximal suspensory ligament and sonographic diagnosis of exostoses of the caudal distal radius; Dr. Katie Garrett, presented how to ultrasound the equine larynx; Dr. Bonnie Barr presented findings on an antimicrobial-associated diarrhea study; andDr. Peter Sheerin lectured on manual reduction of twins in the mare. Additionally, Dr. Rolf Embertson and Dr. Larry Bramlage served on panels for table topic discussions and Dr. Steve Reed co-hosted the Kester News Hour session (above right), a well-attended forum featuring reports on research that are too brief or new to be included in the scientific program. Rood & Riddle technician, Sheri Miller, LVTalso spoke in Baltimore at the American Assoication of Equine Veterinary Technicians program. Sheri presented Radiographic Anatomy of the Equine Fetlock.

OEPS (Opportunities in Equine Practice Seminar) received a “tip of the hat” during the Kester News Hour at AAEP. The Kester team paused to acknowledge the success of the annual seminar for veterinary students, which has become the largest student recruitment and career forum for equine veterinary medicine with over 3,500 students attending the program. Dr. Bill Rood was instrumental in launching the program by bringing together equine practitioners, veterinary industry professionals, and the AAEP to support the first seminar in 2003. He continues to act as organizing host each year and remains committed to the mentorship of veterinary students and the growth of equine veterinary profession.
Dr. Woodrow Friend also received honors during the AAEP convention as a finalist for the Bayer HealthCare Legend of the Year award, an award that is given for extraordinary efforts to benefit the unwanted horse. Bayer Animal Health initiated the award to honor veterinarians for selfless and uncompensated efforts to provide exceptional care for abused or neglected horses. Nominations are made by horse owners and veterinary professionals.
Rood & Riddle Equine Hospital will host the second annual North American Veterinary Regenerative Medicine Conference in Lexington, KY, June 2-4, 2011. The conference, heldin collaboration with the UC Davis Center for Equine Health, Alamo Pintado Equine Medical Center and the newly formed North American Veterinary Regenerative Medicine Association, is a three-day working meeting consisting of scientific presentations and discussion sessions on all aspects of stem cell therapy and regenerative medicine in horses and small animals. The conference is open to veterinarians, regenerative medicine researchers and other interested professional medical personnel and will bring together researchers and practitioners to discuss and apply this promising area of veterinary medicine. Topics will be a blend of research and practical application discussions. A new horsemen’s session has been added to the 2011 NAVRMC. The half-day forum, set for June 4, is open to all horse owners, trainers, and equine professionals who are interested in learning more about this rapidly growing area of veterinary science. Registration and program information will be announced in March.

Rood & Riddle congratulates scholarship recipient Jennifer Lynn Brogie. Jennifer, whose career goal is to become an equine veterinarian, is a sophomore at University of Kentucky majoring in Equine Science. She is active in Pre-Vet Club and the UK Dressage Team. Rood & Riddle makes an annual gift to the University of Kentucky Equine Initiative with a portion of the donation designated towards scholarship awards.

We are very pleased to report that Iman Du Golfe, the Italian Eventing horse who was injured at the 2010 Alltech FEI World Equestrian Games in Lexington, returned to Europe healthy and sound at the end of December. The horse suffered a significant laceration after hitting a jump during the cross country phase of the competition and was taken to Dr. Brett Woodie for surgery at Rood  & Riddle. Imam Du Golfe (shown at farm, on left) was released from the hospital in mid-October and was under the care of Dr. Chris Newton at Knockgriffin Farm before returning to Italy.   You can read the full story on the Lexington Herald Leader website (click here)



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