Underwater Fitness Tracker For Horses

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Inflammation can be an enemy or a friend depending on the situation, but most agree that long-term, it is bad news. Here is an intriguing study that examines one potential way to mitigate these effects.

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Treatment for Grape Toxicity in Dogs.

The first report of grape-induced acute kidney injury (AKI) in dogs was published over 20 years ago, and despite recognition of the condition, no specific treatment or antidote exists beyond decontamination and intravenous fluids. In a study of 120 dogs with grape ingestion, 6.7% developed AKI and one died, illustrating the potential severity of toxicity. In 2022, tartaric acid was identified as the likely toxic agent. Dogs lack the renal transporter OAT-4, which in humans helps excrete tartaric acid, leading to toxic accumulation in canine proximal tubular cells. Recent in vitro work demonstrated that probenecid, an OAT-1 inhibitor, blocks tartaric acid uptake into canine kidney cells, prompting investigation of its potential use as a protective therapy. 

This study evaluated the pharmacokinetics and safety of oral probenecid in healthy dogs at a dose of 50 mg/kg. Probenecid was well tolerated, with only transient soft feces observed, and bioavailability was high at 82.6%. Plasma concentrations achieved (Cmax 589.3 μM) exceeded levels previously shown to block tartaric acid uptake in vitro. The drug was rapidly absorbed, with Tmax of 1.5 hours, and had a long half-life of 24.1 hours, similar to previously reported IV data. Importantly, pharmacologically active concentrations were reached and maintained, suggesting that probenecid could plausibly block tartaric acid nephrotoxicity in vivo. Laboratory changes such as mild increases in nucleated red blood cells and CK activity were observed but deemed clinically unimportant and likely unrelated to treatment. 

Comparison across species showed high oral bioavailability in humans (100%), horses (91.2%), and dogs (82.6%), with dogs exhibiting the longest half-life. Probenecid is already widely used in humans for gout and to prolong antibiotic concentrations, with minimal toxicity risk. The study’s limitations include a small sample size, the absence of a control group, and restriction to healthy dogs. Nevertheless, the findings demonstrate that oral probenecid is safe, bioavailable, and achieves plasma levels that could be protective against grape toxicity. Future clinical studies in dogs exposed to tartaric acid are warranted to evaluate its therapeutic potential as an outpatient treatment option to reduce morbidity and mortality. 

M. Cook, D. L. Gustafson, K. Kroeker, S. Shropshire, and K. M. Zersen, “ Evaluation of the Safety and Pharmacokinetics of Single-Dose Oral Probenecid Administration in Healthy Dogs,” Journal of Veterinary Internal Medicine 39, no. 5 (2025): e70221, https://doi.org/10.1111/jvim.70221. 

Bottom line — Shows promise but needs more studies.

Vitamin D for Chronic Inflammation.

This study explored the broader immunological role of vitamin D in dogs, building on extensive human data and limited veterinary research. Vitamin D is known to regulate calcium and phosphorus metabolism, but its active metabolite, calcitriol, also influences immunity and inflammation through the vitamin D receptor, which is expressed in many tissues. In dogs, in vitro work has demonstrated that calcitriol can suppress pro-inflammatory cytokines such as TNF-α, and observational studies have linked higher circulating vitamin D levels with reduced inflammatory responses. However, the immunologic effects of oral supplementation had not been assessed previously in vivo. 

Researchers administered calcifediol orally to healthy dogs with low vitamin D status and found that both low- and high-dose supplementation rapidly increased serum 25(OH)D3 concentrations by over 150% and 300% within seven days, without evidence of toxicity or changes in ionized calcium, creatinine, or BUN. Increased vitamin D concentrations were associated with reduced production of the pro-inflammatory cytokine IL-6 in response to LPS stimulation. This confirmed an anti-inflammatory effect similar to that observed in people. While visual data suggested a parallel reduction in TNF-α, the association was not statistically significant, likely due to the small and heterogeneous sample population. IL-10, an anti-inflammatory cytokine, was unaffected, contrasting with some in vitro findings where effects varied by disease state and experimental conditions. 

Carryover effects complicated interpretation: vitamin D levels remained higher than baseline even after a 28-day washout, and placebo-treated dogs also showed a decline in IL-6 production, suggesting residual effects of prior supplementation. Despite this, regression analysis strongly supported a causal link between rising vitamin D levels and suppression of IL-6. 

Overall, the trial demonstrated that short-term oral calcifediol supplementation is safe and can shift the cytokine milieu toward an anti-inflammatory profile in dogs, consistent with findings in human medicine. The results highlight vitamin D’s potential as an adjunct therapy in canine diseases involving chronic inflammation. Larger, longer-term trials with broader immune profiling are needed to refine dosing strategies, evaluate sustained safety, and determine whether these immunomodulatory effects translate into clinical benefits. 

 J. A. Jaffey, R. Kreisler, R. C. Backus, D. Gordon, and L. Chittick, “ Effects of Short-Term Calcifediol Supplementation on Leukocyte Cytokine Production in Healthy Dogs: A Randomized, Double-Blinded, Placebo-Controlled Crossover Trial,” Journal of Veterinary Internal Medicine 39, no. 5 (2025): e70240, https://doi.org/10.1111/jvim.70240.   

Bottom line — It seems to be safe in the short term, based on this study.

Fitness Tracker in Horses.

This study evaluated whether a wearable fitness tracker (FT) that functions like a single-lead ECG could reliably measure heart rate (HR) and heart rate variability (HRV) in horses during swimming compared to a reference multilead ECG system (RM). The FT was easy to apply and provided HR values nearly identical to the RM, showing excellent agreement and interchangeability for monitoring heart rate underwater. Bland–Altman analysis and RMSE values confirmed that the two devices produced almost identical HR results, indicating that HR monitoring during swimming can be done effectively with the FT. 

However, results for HRV parameters showed less agreement. While HRV can offer insights into training status, overtraining, stress, and recovery, the FT tended to introduce bias and greater variability as HRV values increased. Specific parameters such as the root mean square of successive differences and SD1 showed clinically significant bias, and DFAα1 values were consistently overestimated compared with the RM. These discrepancies suggest that HRV results from the FT cannot yet be relied upon without adjustments. The variability seen in Bland–Altman plots indicated violations of assumptions of uniform variance, reinforcing the need for nonparametric approaches and further validation. 

Although arrhythmia detection was not the focus of this study, both systems confirmed the low prevalence of arrhythmias during swimming. Still, arrhythmia assessment remains best suited to multilead systems like the RM, requiring expertise and manual data corrections. Limitations included the inability to use the same electrodes for both systems and motion artifacts that sometimes affected one device differently from the other. 

In summary, the FT proved to be a user-friendly, practical option for monitoring heart rate during equine swimming exercise, but its HRV outputs require caution. Bias and variability limit its clinical usefulness for HRV analysis without additional validation and correction. The study highlights the promise of wearable devices for daily fitness monitoring in horses, while emphasizing that HRV analysis underwater still demands further refinement before it can be applied confidently. 

Kisilevich, Q., O’Connor, S. G. P., Bayly, W. M., & Léguillette, R. (2025). A fitness tracker can be used interchangeably with a reference method for underwater single-lead electrocardiography but not heart rate variability analysis in swimming horses. American Journal of Veterinary Research https://doi.org/10.2460/ajvr.25.04.0113 

Bottom line — Potentially useful for heart rate, but use cautiously for HRV and fitness.

Just putting things in perspective …