There is no single age at which a horse becomes a senior. Some are still hacking happily at 25, while others begin to show their years in their late teens. What matters is not the number on the passport but how the horse looks, eats and behaves. The key is to review the diet regularly rather than wait for ribs to appear, because weight loss in older horses is much easier to prevent than to reverse.

Why senior horses need a rethink

Ageing changes the horse from the inside out. Molars become worn, cupped or loose, and gaps between teeth can trap food. Saliva production may drop, making dry forage harder to soften, and the gut's ability to ferment fibre becomes a little less efficient. Muscle tone along the back and topline reduces, which can make a horse look thinner than it is, while some older horses put on weight easily because their work has reduced but their ration has not.

Senior horses also struggle to regulate their body temperature, so they burn more energy keeping warm in winter and can overheat in summer. Add in conditions such as pituitary pars intermedia dysfunction, laminitis or arthritis, and it is clear that a one-size-fits-all veteran mix rarely does the job. The correct ration is the one that suits the individual horse in front of you.

Teeth first: the foundation of any feeding plan

Before you change a single feed, book a dental examination with your vet or an equine dental technician. Most horses over 15 need checking every six to twelve months, and more often if problems are found. Watch for the warning signs at feeding time:

• Quidding — dropping half-chewed wads of hay or grass from the mouth
• Eating very slowly, or leaving long fibre behind while eating bucket feed
• Undigested grain or coarse fibre in the droppings
• Bad breath, facial swelling, head tossing or fussiness with the bit
• Weight loss despite a generous ration, or recurrent colic

If teeth are the problem, no amount of extra feed will fix it. Once the mouth is comfortable, the diet can do its work.

Condition scoring: your fortnightly check-in

Get hands on your horse rather than relying on how they look under a rug. Use a body condition score from 0 to 5, where 0 is emaciated and 5 is obese. Most senior horses should sit at around 2.5 to 3. Feel the ribs, the spine, the hips and the tailhead, and judge the crest and the fat over the shoulders.

Run a weigh tape around the girth every two weeks, at the same time of day with the same person doing it, and record the figure alongside a photograph. A tape does not give a true weight, but it tracks change beautifully. A slow, steady loss is easy to miss until it becomes serious, and the tape will catch it early.

Choosing soft feeds and soaked fibre

Forage must remain the backbone of the diet — aim for at least 1.5 per cent of bodyweight in dry matter each day, ideally closer to 2 per cent. If hay is too hard to chew, consider these alternatives:

• Soaked hay — twenty to thirty minutes in clean water softens it enough for many horses with worn teeth
• Steamed hay — softer than dry hay and useful for horses with respiratory sensitivity
• Haylage — often softer and more digestible, though richer, so introduce it gradually
• Hay replacers — soaked grass nuts, unmolassed sugar beet pulp, chopped alfalfa or hay cobs, fed in a bucket

Offer several small haynets or loose hay in a wide, raised manger rather than a single net, and use larger-holed nets or none at all. A horse that cannot chew efficiently will exhaust itself against a small-holed net and give up. If more than half the forage is being replaced, weigh the soaked feeds carefully so the ration stays balanced.

Building the bucket feed

The bucket is where you top up energy, protein and micronutrients. Good options for older horses include:

• A soaked fibre base — grass nuts, sugar beet pulp or alfalfa pellets — for chewable calories
• Micronised linseed for condition, coat and omega-3 fatty acids, fed at 100 to 200 grams daily
• Vegetable oil as a palatable energy source, building up slowly to 100 to 200 millilitres per day
• A balancer rather than a mix, to supply quality protein, lysine, vitamin E and minerals without extra starch
• Digestive support such as yeast or prebiotics, which can help older guts make the most of fibre

Keep individual meals small — no more than about 1.5 kilograms of concentrate at a time — and split the ration across two, three or even four feeds a day. Add a little warm water to make a mash, which is easier to chew, encourages drinking and is often eaten with more enthusiasm.

Routine, warmth and knowing when to ask for help

Older horses thrive on routine. Feed at the same times each day, keep them with familiar companions, and provide shelter and rugging so they are not spending calories fighting the cold. Check water troughs twice daily in freezing weather, and consider warm mashes overnight.

If your horse loses weight despite good teeth and a generous, well-balanced ration, speak to your vet. Conditions such as PPID, gastric ulcers or kidney disease can all masquerade as simple old age. A check-up, and perhaps a blood test, may open the door to treatment that makes feeding far easier. With patience, regular condition scoring and the right soft feeds, most senior horses can enjoy a comfortable, well-fed retirement.