Merck Animal Health Partners in Practice Magazine: Fall 2023

ISSUE NO. 9 | Fall 2023

MAGAZINE

NEW TIMING

for EIV Boosters?

RON’S CAMPFIRE

UNCONDITIONAL

A Penny Saved

Update from Gluck Research Fellow on EPM Studies

PARTNERS IN PRACTICE | Fall 2023

BUSINESS TIPS A Time-Saving Approach to Care

NEW TIMING FOR EIV BOOSTERS?

Data shows that a shift in vaccination planning may help combat the rising trend of equine influenza.

quine flu season is looming. December to May represents a significant increase in positive cases of equine influenza virus (EIV), according to data from the ongoing (2008-present) Merck Animal Health Equine Respiratory Biosurveillance Program.

While EIV impacts horses throughout the year, the seasonality of infection may warrant re-evaluation of the timing of routine vaccination. As an alternative to biannual vaccination strategies, you may consider: • Shifting August/September booster vaccinations to November/December • Continuing with biannual vaccinations in spring and early fall with the addition of a third EIV booster vaccination in November/December for horses experiencing a high risk of exposure and potential loss in training/preparation for winter events. Flu Avert® I.N. could be a smart choice in these situations (see more below) • W hile horses of all ages, breeds and lifestyles are at risk of EIV, Quarter Horses less than 9 years old with a history of recent travel (14 days) are affected most often1 EIV qPCR-Positive by Season (2008-2021)

40 35 30 25 20 15 10 5

Winter (Dec-Feb)

Spring (Mar-May)

Summer (June-Aug)

1. C happell, D.E.; Barnett, D.C.; James, K.; Craig, B.; Bain, F.; Gaughan, E.; Schneider, C.; Vaala, W.; Barnum, S.M.; Pusterla, N. Voluntary Surveillance Program for Equine Influenza Virus in the United States during 2008–2021. Pathogens 2023, 12, 192. https://doi.org/10.3390/pathogens12020192. 2. Merck Animal Health and University of California, Davis (Nicola Pusterla). Infectious Upper Respiratory Disease Surveillance Program. Ongoing research 2008–present. 3. AAEP Vaccination Guidelines: aaep.org. 4. Townsend HGG. Onset of protection against live-virus equine influenza challenge following vaccination of naive horses with a modified-live vaccine. Unpublished data.

PARTNERS IN PRACTICE | Fall 2023

Fall (Sept-Nov)

Minimizing EIV impact EIV continues to be one of the most common respiratory pathogens of the horse, running neck and neck with equine herpesvirus type4 (EHV-4). In fact, EIV-positive cases are trending up overall from 2008 to 2021.1 As such, EIV presents tremendous economic impact to the industry in lost training and competition time. And it’s no picnic for our horses. Fortunately it carries a low mortality rate, but the morbidity rate is high (except for donkeys, who experience high morbidity and mortality). What’s more, EIV can lead to secondary infections and pneumonia, which can be particularly challenging to manage. Vigilant biosecurity measures, including vaccination planning, help combat EIV and its impact. To be most effective against today’s circulating equine influenza virus, choose vaccines that include Florida ’13. Ongoing research through the Merck Animal Health Equine Respiratory Biosurveillance Program at the time of this article shows Florida ’13 is the vaccine strain closest to today’s equine influenza virus.2 Only PRESTIGE® vaccines from Merck Animal Health contain Florida ’13. In high-risk situations, consider a modifiedlive vaccine such as Flu Avert® I.N., a nonadjuvanted, non-injectable intranasal vaccine, simply administered through a short nasal applicator. An intranasal EIV vaccine is recommended for use during outbreaks,3 and Flu Avert I.N. features a rapid onset of immunity, within 5-7 days of administering the single required dose.4 Flu Avert I.N. is an ideal choice for horses of any age who have experienced past adverse reactions associated with injectable vaccines.

Merck Animal Health Merck Animal Health

HORSE TIPS Timely Health Tips to Share with Horse Owners While vaccination remains the most effective way to protect horses from equine influenza, biosecurity measures also play a part, especially when horses are traveling. Reinforce a few simple biosecurity precautions clients can take to increase their horses’ protection when they’re away from home.

Take these easy biosecurity tips on the road Horses being transported or shipped and those competing are particularly susceptible to infectious disease, especially equine influenza, because they come into contact with many horses and environments and often are immunocompromised (immune system doesn’t respond appropriately) due to stress. To help, take these simple biosecurity measures when your horse is traveling: •M inimize nose-to-nose contact with other horses. •D on’t share items, including lead lines, halters, water buckets or tubes of oral medications. •R egularly clean your tack, equipment and stalls. •M onitor your horse’s temperature daily so you’ll know what’s “normal.” Deviations from normal might signify an infectious illness. Contact your veterinarian if you note a rise in temperature. •P ractice good hand hygiene, washing your hands after handling each horse. (Hand sanitizers work well if soap is unavailable.) •K eep horse health records on hand at all times (health certificates are required for entry at most events and shows).

Fall 2023 | PARTNERS IN PRACTICE

Ron's Campfire

A PENNY SAVED

This installment of Ron’s Campfire is an original piece written by Steve Montemarano, Merck Animal Health Equine Customer Manager, Sales — FL, GA, AL.

I sat upon an upside-down water bucket in the shedrow holding a shank as the Thoroughbred soaked a newly bowed tendon. The colt, nicknamed Penny, looked well—his coat gleamed. The morning training activity proceeded but we were excluded. There were people shuffling through the trainer's office. They were not the usual visitors. The office activity concerned Penny's future. His injury instantly reduced his worth from thousands of dollars to fifty cents a pound. The trainer was under pressure to do something. The stall needed to be filled and the owner's expense minimized. I looked at Penny and felt his vulnerability. Another rider said, “It's a shame; he'd make a good riding horse. He's got sense.”

Penny with Steve Montemarano 4

PARTNERS IN PRACTICE | Fall 2023

His swollen foreleg radiated heat as it was wiped dry. Something had to be done. With the urging of barn help, I made an offer to the trainer. His reply was: “You've got kids to feed; what the heck you gonna do with that horse?” After some debate he said, “OK, get that sum bitch outta here.” The trainer refused any money. The odyssey of horse ownership began.

Penny arrived at a small farm near Monmouth Park. After some acclimation, we held our breath and led him into a small field. Penny was a strapping colt who required two grooms to lead him to the paddock. Yet, after unsnapping the shank, he thrust his head into the grass and calmly grazed. Then he rolled, and groaned, and rolled again. His competitive fire was matched by good judgment. I knew this would work. We learned a lot from each other. But I learned more from him. He taught me how to ride and never once tried to buck me off. In order to manage expenses, Penny was rough boarded. The pasture and fencing were good and there was a neatly bedded stall for shelter from stormy nights. I visited every morning and evening to feed and check up on him. In 13 years he never missed a meal. If I was stressed out, he would let me know. He mirrored my everyday outlook on life. When we came to common ground, he would take a deep breath and exhale with that distinctive nasal flutter. We were at peace. Sometimes the days were long and the chores many. Cold winter mornings made me question horse ownership, as water trough ice chards sprayed in my face with each hammer blow. Sometimes the feed bill was due at the same time as the car payment. But these feelings were short-lived. There's nothing as satisfying as seeing a happy horse swing its head over the stall webbing while munching on clean hay. Even better was his expression when eating a hot bran mash on a winter's night. The bran would cover Penny's face like a child eating a Fudgsicle. Then I had significant life changes, financial uncertainty, and a 600-mile move to another state. I worried about Penny and how to care for him. As if from heaven, a veterinarian contacted me about a client who desired another horse. When I asked further, the vet only said, “It's horse heaven.” So, with mixed feelings, I checked it out. The farm was idyllic. A stall door opened into a 10-acre grass paddock. There was good fencing and an indoor riding arena with a shredded leather base. The only shredded leather Penny had seen to that point was his old halter. There were other horses, deer, and even a famous rock 'n' roll star as a neighbor.

I whistled in the customary way. He galloped straight into the stall in no time flat. He then arched his neck over the door and laid it on my shoulder. The farm owner cried and said Penny will always be mine. I hoped someday Penny and I would be together again. After a stop with Jennifer Buchholz, VMD, Penny returned to Ohio. The Stakes-placed gelding became a favorite for children’s pony rides. Never flinching. One morning Penny laid in his stall and couldn’t get up. I saw him laying headlong into the aisle. It seemed we were too late. Then he raised his head and nickered. I sat there with his head in my lap just talking and thanking him. Then, at 30 years old, he was gone. Decades of memories flashed by. I’m here today at Merck Animal Health because of Penny and the people met along the way. Amazing what the horse can do for us all. A version of this story was previously published in BloodHorse.

There are no greater stories to be told than those of the horse lover. Pull a chair up to Ron’s Campfire to read inspiring, touching or just plain funny tales from the people who make up our equine community. If you have a story or blog you’d like to share, we’d love to feature it. Please email Ron McDaniel to learn more or to submit contributions.

The owner and I talked. She told me her daughter recently passed away, as did her favorite horse. I spoke to her about personal hardship too; things you could never say to most. We drank bourbon and wiped our tears. When I loaded Penny into a two-horse trailer for the short van ride he followed without a balk, his trust unfailing. A few months later, I visited him. As he grazed 100 yards away, Fall 2023 | PARTNERS IN PRACTICE

Unconditional

UPDATE FROM GLUCK RESEARCH FELLOW ON EPM STUDIES Izabela De Assis Rocha, BVM, PhD candidate, a research fellow at the Gluck Equine Research Center at the University of Kentucky, has been studying equine protozoal myeloencephalitis (EPM) and Sarcocystis neurona for over a year with support from the Merck Equine Research Fellowship. Dr. Rocha says the fellowship was paramount to provide funding for a significant portion of her graduate training. “In a moment where funds for research are more and more scarce, I am glad that Merck Animal Health was willing to partner with the Gluck Equine Research Center to provide resources for training a new generation of scientists,” Dr. Rocha says. “Merck Animal Health also provided me opportunities to share my research with a large and diverse audience at the ACVIM luncheon on emerging and re-emerging equine diseases. That was not only an incredible training opportunity, but also a great way to share novel research findings with equine practitioners that frequently work on EPM cases.” In this Q&A, Dr. Rocha provides an update on her research and learnings about treating EPM.

What have you been studying? My primary research focuses on understanding the mechanism of action of diclazuril [Protazil® (1.56% diclazuril) Antiprotozoal Pellets] and related compounds on apicomplexan parasites, including Sarcocystis neurona, the causative agent of EPM. So far, we have identified a transporter molecule that is involved in diclazuril’s mode of action. The transporter is localized to the parasite’s apicoplast, a unique organelle present in apicomplexan parasites but not in mammalian cells. That is very exciting, as it shows that diclazuril targets a pathway that is not shared between the parasite and mammals, which adds evidence to the specificity and safety of this drug. How has your research been progressing? In the last year, we have explored several methodologies such as transmission electron microscopy and genome editing to better understand the importance of this transporter to the parasite’s biology. Currently, we are working on a digital PCR approach to determine whether mutations in the transporter affect the parasite’s growth rate. What have you learned that was surprising? I was surprised to learn that diclazuril is able to halt parasite growth in cell culture at very low concentrations. However, treating horses with EPM is tricky. We know that the treatment success rate is 60-70%, and I believe that may be related in part to the chronic and inflammatory aspects of the disease rather than the antiprotozoal efficacy. Based on that, my plan is to expand my research to investigate inflammation in the central nervous system during EPM in order to develop ancillary regenerative approaches to treatment. What results are you most looking forward to finalizing? Most of the initial research plan is already finalized. The digital PCR experiments are still being conducted, and we plan to

IMPORTANT SAFETY INFORMATION: PROTAZIL® is contraindicated in horses with known hypersensitivity to diclazuril. The safety of Protazil in horses used for breeding purposes, during pregnancy, or in lactating mares, and use with concomitant therapies in horses has not been evaluated. Do not use in horses intended for human consumption. Not for human use. For complete safety information, refer to the product label. 6

PARTNERS IN PRACTICE | Fall 2023

transfect S. neurona with a mutated copy of the transporter gene to augment our findings in Toxoplasma gondii. Those are exciting additional experiments that will help us better characterize this drug transporter. As with all research, there is always more to do. In our case, biochemical studies and knock-down experiments would provide information about the transporter structure and natural substrates and its function. I look forward to following up on that during my postdoctoral training.

Fall 2023 | PARTNERS IN PRACTICE

Business Tips

A TIME-SAVING TEAM APPROACH TO CARE

BY PHILIP VAN HARREVELD, DVM, MS, DACVS-LA Most horse owners call on a number of equine care providers like massage therapists, dentists, chiropractors, acupuncturists, saddle fitters and even animal communicators. That’s a lot to manage—for them and you. To use a construction analogy, you cannot have seven different contractors doing maintenance on the same property. A general contractor is needed to oversee them all. In the same way, assembling a core health team helps clients make confident decisions, positions you as a leading partner and, if done right, ultimately streamlines communications. When all team members play their roles, you get a well-organized healthcare approach that’s better for you, the client and, most importantly, the horse.

Your role: Lead health advisor Even if you’re not a firm believer in all types of ancillary services, keeping an open line of communication about them helps you maintain an accurate view of the horse’s overall health. It also confirms your position as the key decision-maker in the horse’s health program. Reinforce your role by helping clients understand that you’ve been educated to tailor all aspects of care to individual horses. Let clients know the annual physical exam is about more than just vaccinations. It not only allows you to discover any problems as early as possible but also provides a vital once-a-year communication opportunity.

The owner’s role: Communication hub Ultimately, the horse owner should take the communication coordination lead. Offer your insight when asked and support your client’s efforts to orchestrate communication among everyone on the horse’s care team.

Trainer’s role: Every-day aficionado You know that trainers are a close second to owners when it comes to noticing changes 8

PARTNERS IN PRACTICE | Fall 2023

in a horse’s health—trainers might even be the first to identify issues. You may get more direct information about ancillary care from trainers representing clients who can’t be at the barn during visits. Working with trainers streamlines your communications and getting their buy-in helps reinforce your recommendations with clients, potentially improving compliance.

Farrier’s role: More than trimming and shoeing Encouraging clients to share yearly baseline radiographs of the horse’s front feet can be extremely beneficial in helping the farrier find early “hidden” concerns and minimize effects of conformation issues.

Horse’s role: The center of it all Ensuring the horse receives the best care is ultimately what matters. This shared goal should drive everyone’s communications, regardless of individual opinions or preferences. A coordinated team creates efficiencies and results in smoother client relationships. After all, when the whole team wins, you and your patients win too.

Fall 2023 | PARTNERS IN PRACTICE

Meet the Team Tell us a little bit about your horse background. I don’t have a horse background; however, we own two Quarter horses, Boone and Gunner. I also enjoy watching our daughter compete on her equestrian team and in our 4-H fair. Occasionally, we get to trail ride, which is always a great way to connect with our horses. If you were a horse, what type would you be? Thoroughbred. There was a time when I played sports that I had some speed. Now I’m more like a retired racehorse. What’s the best horse advice you’ve ever received? Some of the best horse advice I ever got is: “Once equine, always equine!” Now I couldn’t agree more.

Q&A DANE DAVIS

SENIOR CUSTOMER REPRESENTATIVE, SALES St. Johns, Michigan dane.davis@merck.com

How long have you been working for Merck Animal Health? I joined the equine team in 2023, but ahead of that I worked for Merck Animal Health for six years in the cattle division and Merck Human Health for another 13 years before that. So far, everyone from veterinarians to customers have all been great. The genuine compassion our equine team shows for horses (and each other) is unmatched, and I’m grateful to be a part of it.

PARTNERS IN PRACTICE | Fall 2023

Outside of the horse world, what is your favorite hobby? When I'm not partnering with my exceptional customers and colleagues, I enjoy spending time with my wife and two kids. I enjoy watching our kids grow and develop and become very competitive in their sports. I also enjoy my property, improving habitat for wildlife, hunting with my kids, looking after our horses and home improvement projects. If there was one thing you would want customers to know about you, what would it be? Although I’m new to the Merck Animal Health equine team, I want customers to know I am a trusted resource for them and sincerely care about their well-being. I authentically try to deliver more of a consultative approach to their business and not just act as a sales rep. Having worked for Merck for nearly 20 years, I feel “unconditional” is what we do. We care for people, horses and overall animal welfare.