Is Colic A Career Ender?

Hello Summarians!

Emergency surgery can be a scary situation on multiple levels. One of the questions that doesn’t always get addressed in the beginning is how the procedure affects long-term goals and performance.

Granted, there are a lot of variables, but outcomes can be hard to predict. That is why it is nice whenever we see studies that help us look at the big picture.

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Libre Metrics in Dogs

In recent years, the use of continuous glucose monitoring systems (CGMS), particularly the FreeStyle Libre, has transformed the management of diabetes mellitus in dogs by enabling continuous, minimally invasive tracking of interstitial glucose levels. These systems provide a wealth of data, including mean glucose (MG), time in range (TIR%), time above range (TAR%), time below range (TBR%), and coefficient of variation (CV%), which offer a more objective view of glycemic control compared to traditional methods. This retrospective study aimed to evaluate whether metrics derived from the FreeStyle Libre correlated with the ALIVE Diabetic Clinical Score (ALIVE-DCS), a subjective tool used to assess clinical signs of glycemic control based on owner observations. 

The study found that TIR%, TAR%, and MG were significantly, albeit weakly, correlated with the ALIVE-DCS. Dogs with optimal glycemic control had higher TIR% and lower TAR% and MG values. The weak correlation is likely due to the subjective nature of the ALIVE-DCS, which is based on recent observable clinical signs and not continuous glucose trends. In contrast, the CGMS metrics provide objective data across a longer monitoring period, offering a broader picture of glucose fluctuations that owner assessments may miss, especially in the presence of concurrent diseases or inaccurate reporting. 

TBR% was not significantly associated with the clinical score, suggesting that hypoglycemic events often go unnoticed or are not captured by the ALIVE-DCS, which is more focused on hyperglycemia-related signs. Additionally, the FreeStyle Libre’s limited accuracy in the hypoglycemic range may contribute to this lack of correlation. Nevertheless, the ability of CGMS to detect hypoglycemia is valuable and may guide more precise insulin adjustments, as supported by previous studies demonstrating its superiority over traditional blood glucose curves. 

CV%, a measure of glycemic variability (GV), was higher in dogs with detected low glucose events, indicating a potential link between increased variability and hypoglycemia risk. However, CV% was not correlated with the ALIVE-DCS and was negatively correlated with MG. This could be due to technical limitations of the Libre system in recording extreme hyperglycemia, lower fluctuations in persistently hyperglycemic dogs, or greater glucose swings in better-controlled dogs due to active insulin adjustments. The absence of correlation with the clinical score further highlights the limitations of subjective evaluations in reflecting true glycemic dynamics. 

While concurrent disease is known to influence GV, the study found no statistically significant differences in CV% between dogs with and without such conditions, possibly due to the small sample size. Interestingly, dogs without concurrent disease had a median CV% below the human-defined variability threshold of 36%, whereas those with concurrent conditions had higher values, hinting at a possible clinical relevance that warrants further investigation. 

Overall, this study provides initial insight into the clinical relevance of CGMS-derived metrics in diabetic dogs, suggesting that TIR%, TAR%, MG, and CV% can be useful tools for assessing glycemic control. These metrics offer an objective, data-driven complement to subjective clinical assessments and could improve diabetes management by revealing glucose patterns and variability that are otherwise undetectable. Limitations include the retrospective design, small sample size, use of non-validated technology (Libre 2), and reliance on a cut-off for ALIVE-DCS that may not fully capture clinical control. Despite these limitations, the findings support the integration of CGMS into routine veterinary practice and underscore the need for future research to standardize interpretation and establish reference ranges for these metrics in diabetic dogs. 

Del Baldo, F., Tardo, A.M., Gilor, C., Mott, J., Da Vela, C., Pergolese, V. and Fracassi, F. (2025), Freestyle Libre-Derived Metrics in Assessing Glycemic Control in Diabetic Dogs. J Vet Intern Med, 39: e70151. https://doi.org/10.1111/jvim.70151 

Bottom line — Other metrics can be useful in helping to assess glycemic control.

Performance After Colic Surgery

This study addresses the prevalent negative perception that horses, particularly jumping horses, do not return to their previous level of performance after undergoing colic surgery. This stigma can lead to delays in necessary surgical intervention, resulting in worse outcomes. Although prior studies have examined survival rates and return to performance following colic surgery in mixed equine populations, this is the first study to use objective performance metrics—such as starts, wins, placings, and jump height—specifically in a uniform group of warmblood jumping horses in the United States. 

Results showed that 68% of horses returned to competition, and 42% of those returned to the same or a higher level of performance. Importantly, there were no significant differences in performance metrics (starts, wins, placings) before and after surgery among the horses that returned. This aligns with some previous studies in racehorses, although others have reported reduced performance, particularly in younger horses. The findings challenge the stigma that colic surgery diminishes athletic ability in jumping horses. 

Age was identified as the most significant factor influencing return to performance. Older horses were less likely to return to the same or higher level of competition, a finding likely tied to the higher incidence of orthopedic disease and more severe lesion types, such as small intestinal strangulating lesions, in this age group. Lesion type did not significantly affect overall return to competition but was linked to whether a horse returned to the same or higher level. Horses with large intestinal nonstrangulating lesions had better outcomes than those with strangulating or small intestinal lesions. 

Discipline also influenced outcomes: jumpers were more likely to return to competition than hunters. The authors suggest that this may reflect differences in owner expectations or beliefs about postoperative prognosis. Interestingly, preoperative win rate did not influence return to competition, indicating no selection bias for only more successful horses returning. Among returning horses, win rate did not significantly change after surgery overall, though a slight increase was noted in jumpers, potentially reflecting greater owner investment in rehabilitation. 

The study's retrospective nature introduces limitations, such as lack of data on reasons for retirement, possible missing competition records, and lack of a control group. Moreover, the study relied on USEF records, which may not capture all competition activity, especially for horses competing outside the United States or in non-USEF events. Future studies should incorporate matched controls and time-adjusted performance metrics to refine the understanding of surgical impact. 

Ultimately, this study provides strong, objective evidence that jumping horses can and do return to competitive performance after colic surgery, helping to counter the stigma and inform veterinary and owner decision-making. The methodology used may also serve as a model for evaluating outcomes of other veterinary interventions in athletic horses. 

Chanutin, S. S., Elliott, C. R. B., Fielding, A. S., Brown, P. M., McCreary, C. A., Bennet, E. D., & Davis, W. (2025). Performance outcomes are not reduced following colic surgery in warmblood jumping horses. Journal of the American Veterinary Medical Association https://doi.org/10.2460/javma.25.04.0244 

Bottom line — They can and do return to competition.

West Nile Virus Immunity

This study investigates the long-term humoral immune response to West Nile virus (WNV) in horses that were naturally and subclinically infected, focusing on the persistence and diagnostic interpretation of neutralizing antibodies in the context of co-circulating orthoflaviviruses in Hungary. West Nile virus, a mosquito-borne member of the Orthoflavivirus genus, is endemic in Europe along with Usutu virus (USUV) and tick-borne encephalitis virus (TBEV). These viruses share antigenic similarities, especially in their envelope (E) protein, which leads to cross-reactivity in serological tests and complicates diagnosis. 

The researchers followed 25 horses from 2019 to 2023, all of which were seropositive for WNV and had no clinical signs of infection. Over time, neutralizing antibody titers against WNV decreased significantly, with 88% of horses testing negative by virus neutralization test (VNT) by 2023. The findings suggest that natural, subclinical WNV infection may not induce long-lasting protective immunity in horses. One horse with a low WNV titer subsequently showed mild neurologic signs during the 2024 transmission season, raising concerns about susceptibility to re-infection and the limitations of relying on IgM ELISAs, which may not detect secondary immune responses due to previously primed memory B-cells. 

The study also documents the first evidence of USUV seroconversion in horses in Hungary. Cross-reactions were noted between WNV and USUV, and in one case, WNV and TBEV, complicating serodiagnostic interpretation. The use of VNTs, particularly conducted in parallel for multiple orthoflaviviruses, is recommended as the most specific diagnostic tool, although even VNTs are not immune to cross-reactivity due to polyclonal antibody responses and conserved epitopes among flaviviruses. Despite this, no consistent correlation was found between VNT titers and ELISA results, suggesting that ELISAs should not be used in isolation for assessing immune protection. 

Age-related immunosenescence may have contributed to the declining antibody levels, as older horses often exhibit reduced immune responsiveness. Additionally, while antibody-dependent enhancement (ADE) is a known concern in dengue virus infections, there is currently no clear evidence of ADE in WNV-infected horses, though previous orthoflavivirus infections may alter the course or severity of subsequent infections. 

Given the waning immunity and potential diagnostic challenges posed by cross-reactive antibodies, the study concludes that monitoring WNV-neutralizing antibody titers in horses in endemic areas is essential. Horses with negligible titers should be considered for vaccination, even if previously seropositive. This approach would help ensure adequate protection and aid in the accurate diagnosis of orthoflaviviral infections amid the increasing threat of co-circulating flaviviruses in Europe. 

C. H. Tolnai, P. Forgách, A. Marosi, et al., “ Long-Term Humoral Immune Response After West Nile Virus Convalescence in Horses in a Geographic Area of Multiple Orthoflavivirus Co-Circulation,” Journal of Veterinary Internal Medicine 39, no. 4 (2025): e70176, https://doi.org/10.1111/jvim.70176. 

Bottom line — Immunity can fade without continued vaccination.

Just putting things in perspective …