What aging metabolic horses need from nutrition plans

Aging horses with metabolic disease are forcing a more nuanced conversation about equine nutrition. A recent The Horse article, written by Stacey Oke, DVM, MSc, argues that older horses with insulin dysregulation, pituitary pars intermedia dysfunction, or both need plans that go beyond generic senior-horse feeding advice, with clinicians balancing endocrine control, laminitis prevention, muscle maintenance, and the realities of declining dentition. (thehorse.com)

That framing reflects a broader shift in equine medicine. Equine metabolic syndrome and PPID are distinct disorders, but they often overlap in older horses, and both can increase laminitis risk through hyperinsulinemia or related metabolic disruption. The 2019 ECEIM consensus statement described EMS as a syndrome centered on insulin dysregulation and noted that exercise can improve insulin sensitivity in some horses, though the benefit depends on the animal’s soundness and clinical status. In practice, that means diet remains foundational, especially for horses with a history of laminitis or limited ability to work. (pmc.ncbi.nlm.nih.gov)

In the new The Horse coverage, experts highlighted a core clinical tension: many aging horses need more nutritional support at the same time their metabolic status requires stricter carbohydrate control. The article says senior-specific feeds may help because they’re often formulated with higher-quality protein, including lysine, to address sarcopenia. But those products still have to be evaluated carefully for starch and sugar content in horses with insulin dysregulation. That aligns with broader guidance from Merck, which notes that ration balancers can help fill nutrient gaps in forage-based diets and warns against large grain-based concentrate meals because of links to laminitis and other complications. (thehorse.com)

The management picture gets even more complicated when dental disease is part of the case. A related The Horse article on feeding horses with equine odontoclastic tooth resorption and hypercementosis, or EOTRH, underscores how painful incisors can suppress intake and body condition in older horses. Nutritionist Laurie Lawrence told The Horse that horses missing incisors may struggle to graze short forage, while postoperative survey data cited in the article found that 72% of horses continued eating normally after discharge and body condition scores improved within three to 18 months after extraction. For veterinarians, that’s a reminder to investigate oral pain and forage access when an older metabolic horse is losing weight, rather than assuming the endocrine diagnosis explains everything. (thehorse.com)

There are also a few useful research signals in the background. The The Horse piece cites a Purdue-led study showing phenylbutazone did not increase insulin secretion in horses with insulin dysregulation, a relevant point for clinicians managing painful, laminitis-prone horses. The underlying study, published in the Journal of Veterinary Internal Medicine, evaluated horses with insulin dysregulation and found phenylbutazone administration did not worsen insulin responses, helping address a common practical concern in these cases. (thehorse.com)

Why it matters: For veterinary professionals, the bigger message is that senior-horse nutrition is becoming a systems problem. A horse with PPID may need pergolide, but medication alone won’t solve low muscle mass, poor dentition, or an inappropriate forage program. A horse with insulin dysregulation may need a low-NSC diet, but if that diet is too restrictive, unpalatable, or physically difficult to chew, the result can be weight loss and frailty rather than metabolic control. The best plans are likely to be highly individualized, combining endocrine monitoring, body condition and topline assessment, dental exams, forage analysis, and feed form changes such as soaked hay cubes, pellets, or mashes when chewing is compromised. ECIR guidance similarly emphasizes pergolide for PPID and diet-plus-exercise as the core of management when insulin resistance is in play. (ecirhorse.org)

For practices, that creates an opportunity to tighten collaboration among veterinarians, equine nutritionists, and dental specialists. It also reinforces the need for clear communication with pet parents: “senior,” “complete,” or even “low starch” labels don’t automatically make a feed appropriate for an older metabolic horse, and body condition score alone may miss clinically important muscle loss. The veterinary value-add is in translating multiple risks into one workable plan. That’s especially true in spring and fall, when pasture changes and seasonal ACTH shifts can complicate management in horses with PPID. (ecirhorse.org)

What to watch: Expect more practical guidance, and likely more product positioning from feed companies, around how to support topline and calorie intake in older horses without increasing nonstructural carbohydrate load, alongside growing attention to dental comorbidities such as EOTRH in metabolic workups. (thehorse.com)