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Hello Summarians!

A conversion therapy case from Colorado is now shaping how veterinary telemedicine gets practiced around the country. That is not a sentence anyone predicted writing.

Also this week: a hand-held device designed for human athletes may offer a new way to objectively diagnose equine back pain, and a commonly used drug for dogs with pulmonary hypertension works well on average but inconsistently across individual patients. Three studies. The most surprising one doesn't involve an animal at all.

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Muscle Pain Measurement In Horses

This study evaluated whether the MyotonPRO, a portable hand-held device commonly used in human medicine, could reliably measure muscle biomechanical properties in healthy horses. Researchers focused on the longissimus dorsi muscle in the thoracolumbar region, an area commonly associated with equine back pain and performance problems. Fifty clinically healthy adult horses of various breeds and disciplines were included. The investigators measured muscle tone, stiffness, and elasticity-related properties on both sides of the back while the horses stood square and motionless.  

The MyotonPRO device worked by applying brief mechanical impulses to the muscle and recording the resulting oscillations. From these oscillations, the device calculated muscle frequency, stiffness, and decrement, which reflects energy dissipation and inversely relates to elasticity. Results showed no statistically significant differences between the left and right sides for any of the measured parameters, suggesting a high degree of symmetry in healthy horses. Strong positive correlations were found between muscle tone and stiffness, meaning that muscles with higher resting tone also tended to be stiffer. Negative correlations between decrement and both tone and stiffness indicated that stiffer muscles generally demonstrated lower elasticity.  

The study also explored relationships between muscle properties and biological factors. Older horses tended to have lower muscle tone and reduced elasticity, findings that mirror patterns observed in aging humans. Body condition score showed limited associations with muscle properties, while sex did not appear to influence results. Researchers noted that laterality, or natural body asymmetry in horses, could potentially explain why some correlations appeared only on the left side.  

Although maintaining horses completely still during measurement was challenging, the researchers concluded that the MyotonPRO is a feasible and promising tool for objectively assessing equine muscle biomechanics. They suggested that the device could eventually assist with injury prevention, rehabilitation monitoring, training evaluation, and the diagnosis of musculoskeletal pain in horses. 

Ribeiro, G., Agrícola, R., Sanchez, M. M. F., Ramos, F. R., Borges, J., Abrantes, J., & Prazeres, J. (2026). Feasibility of a hand-held myotonometry device for measuring biomechanical muscle parameters in horses. American Journal of Veterinary Research https://doi.org/10.2460/ajvr.26.02.0050

Bottom line — Promising new tool

Telemedicine Legality

The article examines the legal implications of two recent court cases involving professional speech and veterinary telemedicine, particularly their effect on the veterinarian-client-patient relationship (VCPR). The first case, Hines v. Pardue, involved a retired Texas veterinarian who offered remote advice through phone calls and emails without physically examining animals. Texas regulators disciplined him for violating the state’s in-person VCPR requirement, but the Fifth Circuit Court of Appeals ruled that because he only communicated with clients and did not prescribe medication or perform procedures, the state’s restriction violated his First Amendment free speech rights. The Supreme Court declined to review the case, allowing the ruling to stand within the Fifth Circuit.  

The second case, Chiles v. Salazar, involved a Colorado therapist challenging restrictions on conversion therapy counseling. The Supreme Court ruled that the law improperly regulated speech based on viewpoint, emphasizing that the therapist’s work consisted solely of verbal communication rather than physical conduct. The article stresses that both cases hinge on the distinction between “speech” and “conduct.” Courts generally provide strong constitutional protection for speech, while states retain broad authority to regulate professional conduct such as prescribing medications, performing procedures, or delivering medical treatment.  

Importantly, the article argues that these rulings do not eliminate VCPR requirements or create a constitutional right to veterinary telemedicine. Existing laws governing prescribing, treatment, and other conduct-based aspects of veterinary medicine remain valid and enforceable. Telemedicine practices involving prescriptions or direct treatment still typically require an established VCPR. The authors conclude that while telehealth remains a valuable tool for education, triage, and specialist collaboration, veterinarians should not assume these court decisions broadly authorize remote practice without compliance with state regulations. Legal guidance is recommended before altering telemedicine practices. 

Goldberg, P. S. (2026). What Hines v Pardue and Chiles v Salazar mean for your veterinary practice—and what they don’t: a plain-language guide for veterinary professionals. Journal of the American Veterinary Medical Association https://doi.org/10.2460/javma.264.7.833 

Bottom line — It depends on jurisdiction.

Sildenafil Kinetics in Pulmonary Hypertension Dogs

This study examined how the drug sildenafil behaves in dogs with naturally occurring pulmonary hypertension (PH), a condition involving abnormally high blood pressure in the lungs. Sildenafil is commonly prescribed in veterinary medicine to improve blood flow in the pulmonary vessels, yet little information previously existed about how the drug is absorbed and processed in dogs with clinical PH. Researchers enrolled 20 client-owned dogs with PH caused by a variety of underlying diseases, including heartworm disease, chronic lung disease, congenital heart defects, and heart disease. Each dog had already been receiving sildenafil therapy before the study began.  

Using sparse blood sampling and population pharmacokinetic modeling, investigators measured plasma sildenafil concentrations after oral dosing. The results showed that sildenafil was absorbed relatively quickly, reaching peak concentrations approximately 2.5 hours after administration, with an elimination half-life of about 2.9 hours. Detectable drug concentrations remained throughout the eight-hour dosing interval, supporting the common clinical recommendation of administering sildenafil every eight hours in dogs with PH.  

A major finding of the study was the substantial variability between dogs in how sildenafil was absorbed and metabolized. The greatest variation occurred in the absorption phase, suggesting that factors such as feeding status, gastrointestinal function, concurrent illnesses, and other medications may significantly influence drug levels. Despite evaluating factors including age, body weight, dose, kidney and liver values, and concurrent medications, researchers could not identify clear explanations for the variability observed.  

The study concluded that while sildenafil generally maintains therapeutic plasma concentrations in dogs with PH, individual responses may differ considerably because of inconsistent absorption and metabolism. Researchers recommended larger future studies with more standardized dosing and sampling protocols to better understand why some dogs respond poorly to therapy and to improve treatment recommendations for canine pulmonary hypertension.

Yata, M., T. C.DeFrancesco, J. D.Bonagura, and M. G.Papich. 2026. “Population Pharmacokinetics of Sildenafil in Dogs With Naturally Occurring Pulmonary Hypertension.” Journal of Veterinary Pharmacology and Therapeutics49, no. 3: 267–273. https://doi.org/10.1111/jvp.70057.

Bottom line — Generally good but individual responses may differ.

Just putting things in perspective …