Geriatric horses receive fewer vet visits, vaccinations and farrier visits as they get older, British research has found.
The research also found that many old horses show clinical signs of disease that may not have been recognised by the owner.
The research was carried out by surveying owners living in Northwest England and North Wales who had a horse aged 15 years or older.
In all, 918 owners of geriatric horses were surveyed and 200 of these horses were randomly selected to be given a clinical examination by a vet.
From the questionnaire, researchers found that as they got older, geriatric horses were less likely to have an annual routine veterinary visit.
With increasing age, fewer geriatric horses were vaccinated against flu and tetanus, and received fewer farrier visits. The fewer routine visits meant there was a reduced opportunity for the vet to identify problems.
When the horses were given a clinical examination, a high prevalence of lameness, dental disease and respiratory problems was found. In some cases these problems had not been recognised by owners.
"This research shows that we need to do more to educate both horse owners and vets about the needs of geriatric horses," said Dr Gina Pinchbeck, from the University of Liverpool, who led the research funded by the equine charity The Horse Trust.
"We also need to give owners information about how to recognise the signs of common illnesses that may affect their older horse," Pinchbeck said.
"The owners involved in this study visibly cared about the welfare of their horse, but weren't always aware of the specific needs of geriatric horses."
Pinchbeck, a senior lecturer in equine epidemiology at the university, said it can be difficult to distinguish between normal aging and signs of disease, so regular veterinary visits are important to help with early detection of these health problems.
Owners of geriatric horses sometimes have misconceptions about issues such as vaccination, or the symptoms of conditions, according to Pinchbeck.
"Owners sometimes think that because their geriatric horse doesn't travel, it doesn't need to be vaccinated. But they often have other horses on the yard that do travel and could pass on the disease," she said.
For the final stage of the project, the researchers have followed about 700 of the surveyed horses for 18 months to gather data on diseases and causes of death among geriatric horses.
To help with this research, The Horse Trust provided information from its Home of Rest, which provides sanctuary to about 100 old horses. The findings of the final stage of the research project will be available in the northern autumn.
The area surveyed is considered representative of Britain, with about 29 per cent of horses aged 15 or older. One quarter of the geriatric horses surveyed were retired and kept as a companion, while three quarters were still in some sort of use.
The clinical examinations were carried out by veterinarian Joanne Ireland, a research assistant at the University of Liverpool, within eight weeks of the questionnaire being received.
Co-researchers in the study are Professor Peter Clegg, professor of equine surgery; and Dr Catherine McGowan, lecturer in equine medicine.