Managing Weight in Older Horses: Both Overweight and Underweight

As horses age, maintaining a healthy weight becomes one of the biggest challenges owners face. Some senior horses pile on the pounds despite modest rations, while others lose condition no matter how much you feed them. Both extremes carry serious health risks, and the underlying causes are often very different.

Understanding why your older horse is gaining or losing weight — and knowing how to respond nutritionally — can add years to their life and dramatically improve their comfort and wellbeing.

In this guide, we'll cover the causes, assessment methods, and practical feeding strategies for managing weight in older horses, whether they're carrying too much or too little.

Why Weight Management Gets Harder With Age

Horses are generally considered "senior" from around 15–20 years of age, though this varies between breeds and individuals. Several age-related changes make weight management more complex:

• Declining dental health — Worn, missing, or damaged teeth reduce the horse's ability to chew and extract nutrients from forage and hard feeds.
• Reduced digestive efficiency — The ageing gut becomes less effective at absorbing protein, fibre, phosphorus, and certain vitamins.
• Hormonal changes — Conditions like Pituitary Pars Intermedia Dysfunction (PPID, commonly known as Cushing's disease) and Equine Metabolic Syndrome (EMS) become more prevalent and directly affect metabolism and fat distribution.
• Loss of muscle mass — Sarcopenia (age-related muscle loss) is common in older horses and can mask overall weight status.
• Reduced activity levels — Less movement means fewer calories burned, which can contribute to weight gain in some seniors.

These factors can even overlap. It's entirely possible for a senior horse to be simultaneously overweight (carrying excess fat) and undermuscled — a combination that's particularly tricky to manage.

How to Assess Your Senior Horse's Weight

Before making any dietary changes, you need an accurate picture of your horse's current condition. Scales aren't always available, so most owners rely on two key tools:

Body Condition Scoring (BCS)

Body condition scoring uses a standardised scale (typically 1–9 in the Henneke system) to assess fat coverage over key areas of the body, including the neck, withers, ribs, loin, tailhead, and behind the shoulder. A score of 5 is considered ideal for most horses.

• BCS 1–3: Underweight — ribs easily visible, prominent backbone and hip bones, little or no fat cover.
• BCS 4–5: Ideal — ribs easily felt but not prominently visible, smooth neck, level back.
• BCS 6–7: Overweight — ribs difficult to feel, noticeable crest on the neck, fat deposits behind the shoulder.
• BCS 8–9: Obese — ribs cannot be felt, large cresty neck, obvious fat pads, apple-shaped body.

Weight Tapes and Calculations

A weigh tape gives you a rough estimate of body weight in kilograms. While not perfectly accurate, it's an excellent tool for tracking changes over time. Weigh your horse at the same time of day, every two weeks, and record the results.

For senior horses, pay close attention to topline condition as well. A horse can appear to have a reasonable BCS while actually losing significant muscle along the back, hindquarters, and neck.

Managing the Underweight Senior Horse

Weight loss in older horses is extremely common and can happen gradually — sometimes so slowly that owners don't notice until the horse is significantly underweight. The first step is always to identify the cause.

Common Causes of Weight Loss in Senior Horses

• Dental problems — The single most common reason. If a horse can't chew properly, it can't extract enough nutrition from hay and pasture.
• PPID (Cushing's disease) — Causes muscle wasting, poor coat condition, and metabolic disruption.
• Parasites — Older horses may have less robust immune responses to internal parasites.
• Chronic pain — Arthritis and other conditions can reduce appetite and increase energy expenditure.
• Reduced feed efficiency — Even with good teeth, the senior digestive system may simply extract fewer nutrients from the same feed.
• Competition for food — In group settings, older horses are often bullied away from feed by younger, more dominant horses.

Feeding Strategies for the Underweight Senior

#### 1. Prioritise Digestible Fibre

If your horse struggles to chew long-stem hay, switch to alternatives that provide the same fibre but in a more accessible form:

• Soaked hay cubes or chaff — Easier to chew and less likely to cause choke.
• Soaked beet pulp — An excellent source of highly digestible fibre and calories. It's gentle on the gut and most horses love it.
• Hay replacer products — Commercial fibre-based feeds designed specifically for horses that can no longer eat hay effectively.

Don't simply remove forage and replace it with grain. Fibre should always remain the foundation of the diet, even if the form changes.

#### 2. Increase Calorie Density

Adding calories without dramatically increasing meal volume is key:

• Vegetable oil — Start with 50ml per day and gradually increase to 100–200ml. Oil is calorie-dense and easy to digest.
• High-fat, high-fibre senior feeds — Look for feeds with at least 8–10% fat and moderate protein (12–14%).
• Avoid excessive starch — Large grain meals can overwhelm the senior digestive system and increase the risk of hindgut acidosis, colic, and laminitis.

#### 3. Support Protein and Amino Acid Intake

Muscle loss is a major component of weight loss in senior horses. To support muscle maintenance and repair, ensure adequate quality protein — particularly the essential amino acid lysine, which is the first limiting amino acid in equine diets.

Soybean meal, alfalfa (lucerne), and specific amino acid supplements can help. Aim for at least 12–14% crude protein in the total diet for underweight seniors.

#### 4. Feed Little and Often

Senior horses benefit from smaller, more frequent meals rather than two large feeds per day. This approach:

• Reduces the risk of digestive upset
• Keeps a steady supply of nutrients flowing
• Mimics the horse's natural trickle-feeding pattern

If possible, offer 3–4 meals per day plus ad-lib access to forage (or a forage replacer).

#### 5. Address Underlying Health Issues

No amount of feed will help if the root cause isn't addressed. Work with your vet to:

• Get a thorough dental examination (at least annually, ideally every 6 months for seniors)
• Test for PPID and manage it with medication if necessary
• Conduct faecal egg counts and deworm appropriately
• Manage pain effectively so the horse is comfortable enough to eat

Managing the Overweight Senior Horse

While underweight seniors get more attention, overweight older horses face equally serious health risks — arguably more so, because excess weight is a major risk factor for laminitis, the most common cause of euthanasia in senior horses.

Why Some Senior Horses Gain Weight

• Reduced exercise — Retirement or reduced ridden work means fewer calories burned.
• Equine Metabolic Syndrome (EMS) — Insulin dysregulation makes the horse prone to obesity and abnormal fat deposits.
• PPID — While often associated with weight loss, early-stage PPID can contribute to insulin resistance and regional fat deposition.
• Overfeeding — Well-meaning owners often continue feeding at the same level even after the horse's workload decreases.
• Lush pasture — Unrestricted access to improved, sugar-rich grass is one of the leading causes of obesity in all horses, not just seniors.

Feeding Strategies for the Overweight Senior

#### 1. Control Forage Intake Without Eliminating It

Never starve a horse to achieve weight loss. Prolonged periods without forage (more than 4–6 hours) increase the risk of gastric ulcers and can trigger a dangerous metabolic condition called hyperlipidaemia, which senior horses and ponies are especially susceptible to.

Instead:

• Feed 1.5% of current body weight in forage per day as a starting point, and adjust based on response. Do not drop below 1.25% without veterinary guidance.
• Use small-hole haynets or slow feeders to extend eating time.
• Soak hay for 30–60 minutes before feeding to reduce water-soluble carbohydrate (sugar) content.
• Choose later-cut, more mature hay with lower energy values when available.

#### 2. Restrict or Manage Pasture Access

Grass can be deceptively high in calories and sugar, particularly in spring and autumn. For the overweight senior:

• Use a grazing muzzle to slow intake.
• Limit turnout to times when sugar levels are lowest (early morning, before sunrise).
• Consider a track or strip-grazing system to encourage movement while limiting grass access.
• Avoid turning out on short, stressed, or frosty grass, which tends to be higher in sugar.

#### 3. Eliminate Unnecessary Hard Feed

Many overweight seniors don't need bucket feed at all. If your horse is maintaining or gaining weight on forage alone, a balancer pellet or vitamin and mineral supplement is usually sufficient to meet micronutrient requirements without adding significant calories.

Avoid:

• Cereal-based mixes and sweet feeds
• Molassed chaffs and treats
• Any feed high in starch and sugar

#### 4. Encourage Movement

Even gentle exercise makes a significant difference. If your horse is still sound enough for light work, regular walking — whether ridden, led, or lunged — helps burn calories, maintain muscle, and improve insulin sensitivity.

For retired horses, environmental enrichment and paddock design that encourages natural movement (such as placing water, hay, and shelter in different locations) can help.

#### 5. Test for Metabolic Conditions

If your senior horse is overweight and resistant to weight loss despite a controlled diet, ask your vet to test for PPID and insulin dysregulation. Both conditions require specific medical management alongside dietary changes.

The Importance of Analysing Your Horse's Diet

Whether your senior horse is overweight, underweight, or somewhere in between, guessing at their nutritional intake often leads to mistakes. Too much of one nutrient and not enough of another is incredibly common — and it can either contribute to weight problems or create new health issues.

Analysing your horse's diet is one of the most valuable steps you can take. A proper diet analysis reveals whether your horse is getting the right balance of calories, protein, vitamins, and minerals for their age, weight, and workload. It takes the guesswork out of feeding decisions and helps you make targeted changes rather than broad, potentially counterproductive ones.

Monitoring Progress

Weight management in senior horses is rarely a quick fix. It requires patience, consistency, and regular monitoring.

• Weigh or tape your horse every two weeks and record the results.
• Body condition score monthly — take photos from the same angle each time to track visual changes.
• Reassess the diet every 2–3 months or whenever there's a significant change in condition, workload, health status, or season.
• Communicate regularly with your vet, especially if your horse has PPID, EMS, or dental issues that affect feeding.

Aim for gradual changes — no more than 0.5–1% of body weight per week in either direction. Rapid weight loss is dangerous for horses, and rapid weight gain can overload joints and increase laminitis risk.

Key Takeaways

• Weight management in senior horses requires understanding the underlying cause — dental disease, hormonal conditions, reduced digestive efficiency, or simply an imbalance between intake and energy expenditure.
• Underweight seniors need digestible fibre, quality protein, increased calorie density, and frequent meals.
• Overweight seniors need controlled forage, restricted pasture, minimal hard feed, and encouragement to move.
• Never starve an overweight horse — this can trigger hyperlipidaemia and gastric ulcers.
• Regular body condition scoring, weight tracking, and diet analysis are essential tools for staying on track.
• Always work with your vet to rule out or manage conditions like PPID and EMS.

Your senior horse has given you years of partnership. Getting their weight right in their later years is one of the most impactful things you can do to keep them healthy, comfortable, and enjoying life for as long as possible.