The population of elderly horses (>20 years old) has risen sharply and this trend is expected
to continue. In order to maintain an animal's health throughout their lifespan special attention
is required to a number of dietary elements in their latter years. This study is focused on
aspects of elderly horse nutrition and their dietary requirements.
When a horse consumes its food ration it is first crushed and salivated followed by transport
to a relatively small stomach where continuous acid production furthers digestion. The
combination of a small stomach and continuous acid production requires the horse to eat at
least every four hours. The food moves from the stomach into small intestine for enzymatic
digestion, followed by the large intestine where the main microbial digestion occurs. This
process is inefficient and results in the loss of some nutrients to waste production.
Elderly horses suffer a slow down of some metabolic processes due to aging. The caregivers
must however learn to recognize the signs of aging and change the environmental conditions
to the benefit of their animal. For example the teeth of an elderly horse need to be checked
regularly to ensure the molars are able to provide sufficient crushing. The digestibility of the
animal feed too should be as high as possible and in order to achieve this effect processes
such as the thermal treatment of grain may be required. The requirement of energy and
crude protein of these animals rises up to 20 %. Elderly horses also have an increased
demand for selenium, zinc, and vitamins A and E.
This study calculated daily rations for a 500 kg elderly horse and considered the metabolic
energy, crude fibre, digestible crude protein, calcium, phosphorus, selenium, zinc, and
vitamins A and E delivered by the ration. The calculated ration however produced a large
energy surplus, thus a feeding approach based on energy demand is expected to be more
beneficial. Due to the consumption of hay the required daily quantities of selenium and zinc
are difficult to achieve requiring an approach that uses supplements. The other elements
show only occasional few deficits/oversupplies.
In practice it is generally assumed that a mineral supplement may be omitted when supplying
the animal with a compound feed. This appears to be problematic for elderly horses, in part,
due to the age of their gastrointestinal tract. Their inability to absorb from their feed for balanced nutrition is recognized. However, an understanding of the full nutritional
requirements for elderly horses is lacking further nutritional studies are required.