Understanding the aging process in horses

There's no single path on which any of us age, whether horse or human, which means we can only determine, only very approximately, when old age finally arrives. After all, in our human world there are people in their 80's running half-marathons, yet a  50yo may struggle to get up the stairs. Lifestyle, genetics, chronic diseases - all factors are important and have an individual impact.

So how do we assess biological age? Well, the scientists say it's an indicator that reflects the degree of deterioration of the body. But how do we assess wear and tear? After all, organs age in different ways and there can be a lot of parameters: joint mobility, metabolic rate, cognitive functions, visual clarity, and let's not forget stress, which is a huge issue for the aging process. And for each of them, the readings will differ from person to person, horse to horse.

It's generally believed that 1-year of a horse's life equals 3-human years. For example, as at October 2018, this would have made my connie, Murphy (him above in the image), 76-years old. Cookie would have been 54, MacAttack 48, and Carmen 36. No wonder Murf was getting less enthusiastic about the saddle back then (by Summer 2019 he politely informed me (planted himself 200-yards outside the yard by the local pub) that he was ready to retire 😉).

The aging horse population

It's estimated that a quarter of the UK’s horse population, if not more, is older than 15 (horse) years of age, so compared to us humans, that’s a large proportion of horses over the age of 45 in human years. And as I type, three of them live with me!

The aging process brings inevitable changes in horses, with many remaining active well into their senior years; yesterday we had a wonderful testimonial with a photo, from a client whose very beautiful TB mare is still ably showing at the age of 24. However, we can't get away from the fact that increased longevity presents new challenges, especially when it comes to maintaining weight and condition.

Common health issues in senior horses

For senior horses that struggle to maintain weight and condition, it's easy to think that increasing calorie intake is the solution. However, this is all part of the aging process and is usually all to do with dental issues rather than insufficient calories. Older horses are less able to chew, because with age brings tooth loss, while worn-down back molars make it difficult for them to chew their forage properly, which can impact digestion.

The chewing and grinding shapes their mouthful of hay into a perfect sized 'hay roll', ready to pass into the oesophagus with the inner fibre exposed and ready for pre-digestion in the stomach. Problems arise when the molars are no longer able to grind the forage down to the right size. The gut will then struggle to digest the starch/protein, which can lead to undigested starch reaching the hindgut, which may cause a drop in pH values, dysbiosis (faulty fermentation), and increased risk of laminitis. Additionally, improperly chewed forage can ferment in the small  intestine, leading to a higher risk of colic.

To address these challenges, if dental issues mean longer fibre can't be chewed properly, older horses may need a fibre source that both teeth and gut can cope with. Cue easily digestible fibres such as hay replacers, and meadow grass cobs with added Sainfoin can be your saviour here.

Nutrition and supplements for senior horses

Soaked meadow hay cobs' forage composition are naturally chopped to replicate the same size of forage fibre that the horse itself grinds down with a full set of healthy molars, in other words, oesophagus-ready. Meanwhile, sainfoin in pellet form is also excellent for senior horses, with its higher amino acid pattern better than alfalfa for protein metabolism. Where it shines, though, is that it’s higher in tannins – bitters – which have a stabilising effect on the horse's intestinal environment, which means the feed nutrients can be better broken down and absorbed. Bitters basically stimulate saliva and the digestive juices into action - think of what happens in your own mouth when you think of eating a slice of lemon, or pickled onions!

Add in sainfoin slowly - remember, it's bitter! Avoid chopped, loose sainfoin as this tends to be just the stems; always go for the pellets as you get the whole plant in pellets, and all the protein is in the leaves and flowers. Start with a small mug then gradually increase – the RDA for a senior on hay replacers is up to 600g/100kg bodyweight.

Many older horses may also experience a malabsorption disorder, meaning that they’ll absorb fewer nutrients from their feed. For this reason it may be necessary to feed more nutrients than the recommended daily allowance; this applies not only to the amount of roughage, but also the daily minerals/trace elements.

Special considerations for the senior horse

It may also be tempting to feed an older, thin horse with large amounts of concentrated feed as quickly as possible, especially in cold winters to provide a portion of 'quick energy', but try to resist as it’s really not the best way to help a horse gain weight. Adding concentrated feed should only be to help support them when the temperatures drop below zero and the older horse needs extra energy to keep warm. Remember, the older horse has to use a relatively large amount of energy for their central heating, which is obtained from the digestion of grass fibres in the hindgut.

If it's really cold, a handful of oats can offer 'quick energy' to help keep the horse warm. You can also soak crushed barley with the hay cobs. Always start small, i.e. half a coffee mug, and increase very slowly over several days. Remember - if you feed too much grain, the risk of laminitis and IR increases, as older horses can no longer adequately regulate their blood sugar levels.

For weight gain, instead focus on muscle mass development, exercise, and fibre-based feeding. Only add if weight can no longer be maintained through a pure roughage diet - i.e. hay, haycobs, sainfoin, as real weight gain through muscle mass takes time, exercise and fibre-based feeding.

Also, don’t be tempted to add oil, as this will do more harm than good. Irrespective of age, liquid oil can’t be digested by the equine gut, and will interfere with the absorption of other nutrients. Instead, add ground oil seeds, such as linseed, hemp, or sunflower, which are better alternatives as they provide fatty acids in a usable form as well as other nutrients without causing digestive issues.

Again, these shouldn't be used to gain weight or generate energy, but essentially represent building materials for regeneration and are used by the horse to produce sebum in order to keep the coat water-repellent and thus save energy again.

Spirulina is also beneficial as it not only has an excellent detoxifying effect, but also a high proportion of essential amino acids.

Signs of aging in horses

The signs of irreversible physical and functional changes in our aging horses:

• Skin and soft tissue elasticity decreases. leading to the typical sunken back of the older horse.
• Teeth are constantly erupting and eventually grow out of the gums, resulting in smoother, less efficient fibre-grinding surfaces on the back molars.
• The immune system becomes weaker, becoming less able to fight disease.
• Circulation, which delivers nutrients and oxygen to the horse, becomes less efficient.
• Liver and kidney function declines, becoming less able to support immunity and detoxify and excrete toxins.
• Joint stiffness - inevitable as the horse ages.
  

Senior feed formulas

Meanwhile, it's also all too easy to be bedazzled by the glossy bags of commerical senior feeds. As the aging changes occur, it's so important to approach senior horse care with caution, becuause if, say, organ function is compromised, many of the 'senior' formulas could actually make matters worse.

For example, many senior feeds have increased protein and fat, which are contraindicated for liver function, and some senior feeds contain higher phosphorous and calcium, which are contraindicated for kidney function.

Thankfully, nature has equipped us to help maintain the health and well-being of our senior horse to keep their inner-systems working in harmony. By carefully selecting the right diet and supplements, we can ensure our seniors rightfully enjoy their golden years.

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