What aging metabolic horses need now: full analysis

CURRENT FULL VERSION: Aging horses with metabolic disease need more than a standard low-sugar feeding plan, according to a March 5, 2026, feature from The Horse that brings together current thinking on managing older equine patients with insulin dysregulation, pituitary pars intermedia dysfunction, or both. The article frames the issue as a convergence problem: age raises the odds of PPID, while longstanding insulin dysregulation, laminitis risk, muscle loss, osteoarthritis, and medication tradeoffs can all collide in the same patient. (thehorse.com)

That background matters because PPID is strongly associated with advancing age. The Horse reports that roughly 20% of horses 15 years or older have PPID, and Equine Endocrinology Group guidance says insulin dysregulation should be assessed in all PPID patients. In practice, that means older horses may shift over time from a relatively straightforward endocrine case to a more complex dual-diagnosis patient whose body condition, laminitis history, and nutritional tolerance need regular reassessment. EEG guidance also notes that feed selection in PPID horses should be based on body condition score and evidence of insulin dysregulation, with monthly monitoring recommended because needs can change over time. (thehorse.com)

On nutrition, the core message is familiar but more nuanced in seniors: restrict sugar and starch, but don’t underfeed the horse. Erica Macon told The Horse that clinicians are moving beyond percent-NSC alone and toward meal-based targets, recommending horses with hyperinsulinemia be limited to about 0.1 to 0.15 grams of nonstructural carbohydrate per kilogram of body weight per meal. The article says forage should remain the basis of the ration, generally around 2% of body weight for horses in good condition, with reductions to 1.75% or 1.5% for weight loss when needed, but not below that because of hindgut health concerns. For lean senior horses, especially those with PPID-related sarcopenia, higher-quality protein and bioavailable amino acids become a bigger part of the equation, often through ration balancers or carefully selected senior feeds and low-NSC calorie sources such as beet pulp without molasses, fats, and oils. (thehorse.com)

The article also underscores how individualized these cases can be. Tania Sundra told The Horse that horses can show different insulin responses to the same diet, likely reflecting factors such as genetics and the gastrointestinal microbiome. That lines up with broader reference guidance from Merck, which recommends not relying on a single normal insulin value to rule out equine metabolic syndrome and instead using dynamic testing, including oral sugar or oral glucose testing, when needed. Merck also recommends monitoring postprandial insulin to judge whether the current diet is truly safe, which is especially relevant in older horses whose pasture tolerance, dentition, muscle mass, and endocrine status may all be shifting at once. (thehorse.com)

Exercise remains a key part of treatment, but the real-world barrier is that many older horses simply aren’t in structured work. The Horse cites a 2024 survey of about 2,700 caretakers of aged horses in which 79% reported little structured exercise. The article points to consensus recommendations supporting low- to moderate-intensity exercise in non-laminitic insulin-dysregulated horses, and carefully monitored low-intensity work in previously laminitic horses whose feet have stabilized. But it also spends time on the osteoarthritis problem, noting that joint pain can limit compliance and complicate efforts to improve insulin sensitivity through movement. (thehorse.com)

That leads into one of the more clinically useful sections: medication tradeoffs. François-René Bertin discussed research suggesting phenylbutazone did not increase insulin secretion in insulin-dysregulated horses and may offer short-term pain relief without worsening hyperinsulinemia. By contrast, The Horse reports continued concern about intra-articular corticosteroids in insulin-dysregulated or laminitis-prone horses, citing work showing systemic metabolic effects after joint injections and advising caution even with betamethasone. For endocrine therapy, pergolide remains the standard treatment for PPID, and EEG recommendations place the starting dose at 0.002 mg/kg once daily, equivalent to 1 mg for a 500 kg horse. For difficult insulin-dysregulation cases, the article and a related April 11, 2026, The Horse report describe off-label SGLT2 inhibitors as an emerging option for severe hyperinsulinemia or horses that have not responded adequately to diet and exercise, not a first-line shortcut. In that related report, Caitrin Lowndes, a research fellow at the Van Eps Laminitis and Endocrinology Laboratory at the University of Pennsylvania’s New Bolton Center, explained that these drugs lower blood glucose and insulin by increasing urinary glucose loss and are being explored specifically for horses at risk of metabolic laminitis. Proceedings from the 2025 Global Equine Endocrine Symposium suggest that research on canagliflozin, dapagliflozin, and ertugliflozin is still active, including longer-term efficacy and side-effect questions. (thehorse.com)

Why it matters: For equine veterinarians, the bigger message is that geriatric metabolic management is becoming more integrated and more labor-intensive. These horses need endocrine monitoring, nutrition planning, hoof care, dentistry, parasite control, and medication review all working together, especially when PPID, insulin dysregulation, osteoarthritis, and recurrent laminitis risk overlap. The evidence base also points toward a more conservative, data-driven approach: test insulin status in PPID patients, monitor body condition monthly, use low-NSC diets without excessive forage restriction, and think carefully before using corticosteroids in laminitis-prone cases. It also suggests that when SGLT2 inhibitors are considered, they should be framed as a targeted tool for refractory cases rather than a replacement for diet, exercise, and hoof-focused management. For pet parents, that means expectations need to be set early: successful management is usually ongoing, and often depends as much on feed-room precision and follow-up testing as on prescriptions. (idppid.com)

What to watch: The next phase of this story will likely come from longer-term endocrine therapeutics data, especially around SGLT2 inhibitors and how newer use patterns translate from referral settings into field practice, plus more work on safer osteoarthritis treatments and practical monitoring protocols for older horses whose metabolic and musculoskeletal issues evolve together over time. (equineendocrinologygroup.org)