When it comes to feeding senior horses, there are many factors to consider to support longevity and healthy aging.
Making sure your horse’s core nutritional needs are met and keeping up with routine healthcare are critical to promoting optimal well-being for many more years to come.
Horses are typically considered “senior” after 20 years of age. However, chronological age isn’t always the best indicator of their health status.
The exact age that classifies a horse as “senior” can vary depending on a multitude of factors such as the horse’s environment, genetics, nutrition and health history over their lifetime.
Looking at a combination of the horse’s chronological and physiological age is generally considered the most accurate indicator of aging in horses. 
Some horses remain very active into their late twenties, whereas other horses may exhibit signs of aging earlier in their late teens.
Common indicators of physiological aging include:
- Decrease in muscle mass
- Decline in coat quality
- Poor dentition
- Decline in comfort and mobility
Formulating a well-balanced diet that supports healthy aging is critical for senior horses. It is particularly important to accommodates changes in health status such as poor dentition or gut health problems.
You can submit your horse’s diet for a free evaluation by our equine nutritionists who can help formulate an age-appropriate diet for your horse.
Nutritional Needs of Senior Horses
Nutritional programs for senior horses will vary greatly depending on the presence of any underlying health conditions. Healthy senior horses with no medical conditions may see excellent results on a similar diet to what they were fed during their mature years.
Many senior horses can maintain a healthy condition on a well-balanced diet and their energy and protein needs may not change significantly as they age. This is especially true if their work level decreases significantly, such as in retirement from a career in competition.
When certain health conditions are present that hinder nutrient absorption, or interfere with normal metabolic function, the digestion of typical feedstuffs like hay can be impacted.
In these situations, feeds that are easier to digest are needed to maintain optimal body condition. Specially-designed senior feeds and/or hay replacement feeds may be needed.
Feeding Programs for Senior Horses
1) Determine Nutritional Needs
As with any balanced feed program, the horse’s individual needs should be considered. This includes the horse’s body weight, work level and current body condition.
Horses in maintenance will require less energy and protein in the diet compared to active horses. Correctly identifying your horse’s work level will help to assess whether calories and protein are in over- or under-supply, which could lead to changes in body condition.
It is recommended to assess your horse’s body condition on a regular basis. Keeping a record of this will allow you to track whether their condition is changing over time.
The ideal body condition is 5 on a 9-point scale. Overweight or underweight horses will need to be fed accordingly to gradually attain a more healthful weight.
2) Identify health conditions early
Aging horses tend to be more prone to health conditions due to a variety of factors.
Depending on the individual horse, it is a good idea to have physical examinations done by a veterinarian twice yearly rather than once yearly. Regular checkups will ensure that any health conditions are detected and managed early on.
Conditions such as Equine Metabolic Syndrome (EMS) require special dietary changes to reduce the risk of laminitis. Cushing’s Disease / PPID requires medication to control symptoms of this progressive disease.
Additional age-related health conditions that may require dietary adjustments include:
- Orthopaedic disease
- Kidney and/or liver dysfunction
Maintain a schedule of fecal testing and strategic anthelmintic treatment to prevent major issues.
3) Check for Dental Issues
Optimal dentition (teeth health) is very important so that senior horses can thoroughly chew hay and other feedstuffs.
Chewing initiates the first step of digestion, helping to break down feed so that your horse can absorb nutrients that they need to maintain optimal body condition. 
Dental problems, such as broken teeth, sharp points, and more serious conditions like equine odontoclastic tooth resorption and hypercementosis (EOTRH) are more prevalent with increasing age.
Signs that your horse may have dental issues include: 
- Quidding (spitting of half-chewed hay balls)
- Dropping feeds when eating
- Halitosis (bad breath)
- Weight loss
- Compaction colic
- Oesophageal choke
Keeping up with regular dental checks will help maintain a healthy chewing surface and detect issues early on.
For senior horses that have had teeth removed, chewing hay can become extremely difficult. Replacing some or all of their long-stem hay intake with chopped hay, soaked forage cubes and/or soaked hay replacer feeds will be needed in order to meet their fibre requirements.
Fresh grass pasture is also much easier to chew than hay. However, fresh grass should only be offered to horses that do not have metabolic issues and are otherwise healthy. Pasture can pose a problem for horses with metabolic issues such as Equine Metabolic Syndrome or horses at risk of laminitis.
4) Select an appropriate forage
Once you have identified a senior horse’s nutritional requirements based on their body weight, body condition score and work level, an appropriate forage source should then be selected.
If your senior horse is underweight or active, they will require a more energy-dense forage such as mixed grass-legume hay. Overweight horses should be given lower quality grass hay to support weight loss without needing to restrict forage intake.
In some cases, straw may be added to the feeding plan to support species-appropriate foraging behaviours while limiting the calorie content of the diet.
5) Feed digestible protein sources
Senior horses frequently struggle with a loss of muscle mass or poor topline.
Horses with health issues that impact digestion often require additional protein sources to maintain optimal muscling and overall health.
Most ration balancers and complete feeds have good quality protein sources added, such as soybean meal, alfalfa products and/or individual amino acids.
The individual amino acids lysine and threonine are particularly important. A study done in 2005 demonstrated that older horses exercised lightly were able to maintain optimal muscle mass when given supplemental lysine and threonine. 
Whether supplemental amino acids are necessary for your horse will depend primarily on forage quality and their exercise level. It is recommended to determine the protein content of your forage via hay analysis before significantly increasing dietary protein.
If your senior horse gets too much protein in their diet, this can put added strain on kidney function. Protein fed significantly in excess of requirements will result in the body breaking down excess amino acids and excreting them in urine.