Feeding the older horse
Professor Jo-Anne Murray
PhD, MSc, PgDip, BSc (Hons), BHSII, RNutr, PFHEA University of Glasgow Veterinary School
As horses age their bodies undergo changes in dentition, degenerative disease and altered gut absorption, all of which can impact on providing adequate nutrition. Weight loss is one of the most common issues, which may be due to disease and hence this needs clinical investigation. It is also important to initially evaluate the horse’s diet as the weight loss may be due to a lack of energy provided in the diet. In general terms, horses that are in good health will eat food when offered, whereas horses that are unwell will often not eat when food is available. However, it is important to note that some horses that are unwell will eat and still lose weight and this may be attributable to poor absorption and or/excessive loss or metabolism of nutrients, which is why it is important to consult with your veterinarian if your horse is losing weight.
Digestive function in older horses
In terms of digestive function in older horses, there are conflicting reports in the literature; for example, some studies have reported a decrease in protein and phosphorus digestibility in aged horses (>20 years) compared to young horses (<10 years). This decrease was attributed to changes in large colon function, possibly due to chronic parasitic damage. However, subsequent studies have shown no difference in digestibility between young and older horses, and it has been suggested that where differences are seen, they are associated with chronic parasitism and poor dentition rather than the age of the horse. Consequently, older horses that are in good health, have no dental issues, and are receiving regular anthelmintic treatment can be fed in accordance with normal adult horse requirements.
For older horses with poor dentition and weight loss it is important to adjust the diet to accommodate these changes. Diet can impact on changes in dentition, when grains and concentrate feeds are fed and forage intake is reduced there is less time spent chewing and less sideways movement of the jaw during mastication. Studies have reported periodontal disease in horses older than 15 years as 60 % and there is a strong correlation between dental disease in horses and poor body condition score.
Managing your horse’s weight
Dietary management of older horses with dental issues should involve turnout on fresh grass (so long as there are no issues with a history of laminitis, EMS or Cushing’s). Feeding high quality forage with a high leaf to stem ratio that are soft and easier to chew is important. For more severe dental problems it may be necessary to avoid long-chop forage sources, such as hay and haylage, and feed an alternative fibre source, such as alfalfa cubes, hay cubes and soaked sugar beet pulp. Alfalfa or hay cubes should be soaked prior to feeding and can be fed at 1 kg/100 kg bodyweight/day fed over 4 feeds. Vegetable oil can also be added to increase the energy content of the diet as oil contains over twice the amount of energy compared to carbohydrates. Oil can be added at up to 100ml/100 kg bodyweight/day and this should be gradually introduced over a period of several weeks starting at 50 ml/day.
It is important to monitor your horse’s weight on a regular basis, at least once a month, but more frequently if the horse needs to lose or gain weight. If weighing weekly, it is important to pick the same day each week and also the same time of day to minimise variability. It is also good to try to ensure that the timing of the weighing is consistent relative to when the horse has been fed or exercised. Body condition scoring (BCS) is also important to monitor, most recommend that this is done on a monthly basis since it takes at least that time for any