Feeding old horses

Once horses reach over 20 years of age, they are generally considered senior or aged-normal horses if they are healthy, regardless of being overweight. Once there are clear signs of senescent changes with possible concurrent disease then they are considered geriatric. For aged-normal horses there is little adjustment needed to the diet except working towards the ideal body condition by addressing weight loss or obesity. With the onset of senescent changes, frequent monitoring to identify, address, and ameliorate the inevitable age-related diseases is recommended. Some common problems seen in the equine geriatric are dental disease, arthritis, pituitary pars intermedia dysfunction (PPID), colic, sarcopenia, body mass loss, and attrition of digestive, neural and immunologic systems. Because of the physiological changes normally associated with aging, geriatrics may require special adaptations in health care, environment and diet.

Dental disease, one of the biggest challenges facing the older horse, is the loss of teeth, wearing down of the grinding surface, and diastemata. Older horses have an increased risk of cecal and large colon impactions due to failing dentition, decreased frequency of preventive dental care and reduced intestinal motility. Signs of dental disease are quidding, food pocketing, hypersalivation, facial swelling, halitosis, weight loss and increased risk of choke or colic. The aim of dental treatment is to preserve occlusal surface where possible, remove sources of pain and provide nourishment in a highly digestible form. When long stem forage and/or pasture become impossible to chew, dietary adaptation to alternative fiber sources will be necessary to facilitate adequate forage intake. Shorter stem forage, like chopped hay or hay cubes, hay pellets, and hay replacer served as a wet mash and offered 3 to 4 meals per day compensate for the lack of pasture or hay intake and reduce choking. The addition of a ration balancer with a concentrated source of protein, vitamins and minerals will balance out the shortcomings of a forage only diet. For underweight horses, a senior or high fiber, low NSC type concentrate feed can be served wet. Dietary fat, such as oil or rice bran can be an additional source of concentrated calories.

Osteoarthritis (OA) is the chronic structural deterioration of articular cartilage, exposure of subchondral bone and pain. Lameness can be overt or subtle, depending on the location of the arthritis. Treatment aims to provide comfort and limit progression of the disease. Commonly, NSAIDs are used to manage pain along with intra-articular corticosteroids or IM PSGAGs. Supplements with glucosamine, chondroitin sulfate, hyaluronate, MSM and other nutrients are commonly used. Omega-3 fatty acid supplements, particularly ones high in DHA and EPA such as fish oil, have been found to help joint inflammation. Weight management is important to prevent chronic overloading of joints. Regular hoofcare to properly balance any abnormal loading through joints is essential. Light exercise is important for maintaining muscle mass and joint flexion, although should not be done during an acute flair of OA. Older horses benefit from not being confined to stalls and to have freedom of movement 24/7 to keep the joints lubricated. Modifications to feed pan location, such as feeding at elbow height instead of ground level may be necessary if OA is in jaw, forelegs or cervical spine.

Pituitary pars intermedia dysfunction is a progressive degenerative disease commonly seen in older horses. The origin of the disease is hypertrophy in the pars intermedia affecting hormone regulation. Some of the signs are hypertrichosis, muscle wasting, lethargy, fat redistribution, laminitis, swelling around upper and lower eyelids, polyuria, polydipsia, excessive sweating, delayed wound healing and susceptibility to infections and endoparasites. PPID is diagnosed with a basal ACTH concentration which can be validated with thyrotropin-releasing hormone (TRH) stimulation test when ACTH results are equivocal. Testing for insulin dysregulation (ID) should be done in PPID horses with laminitis. Pergolide mesylate is recommended for management of PPID. Nutritional management will be dependent on whether the horse is appropriate, over- or under-weight, as well as ID and/or laminitic. For PPID horses with ID, maintenance on a low non-structural carbohydrate (NSC) diet is essential. Low NSC hay (< 10%) is ideal, although higher NSC hay soaked for 60 minutes to leach sugar can be an option. If hay is low in protein or soaked, it is important to supplement with a ration balancer with quality protein to discourage muscle wastage. Overweight PPID horses do well on forage balanced with a quality ration balancer, and those with ID may need to be restricted from pasture. PPID horses that have difficulty maintaining weight may need a low NSC, high fat concentrate feed. To support a healthy immune system, supplement with antioxidants such as vitamins C, E and A, selenium, zinc, and alpha lipoic acid. It is important to stay on top of deworming and vaccination schedules. Clipping the coat may be needed in hot weather and regular bathing to discourage skin disease.

For older horses maintained in a herd, careful observation of bullying or loss of interest in fighting for food so that modifications can be done will minimize stress. Separation for feeding will give a horse more opportunity to eat the entire meal and to monitor feed intake. Thermoregulation is often altered in the older horse from loss of fat cover, changes in hormonal temperature regulation, and decreased heat production from fiber digestion. Shelter and/or blanketing in adverse weather and colder temperatures may be needed. During cold weather, reduction in water intake can result in colic and subsequent impaction due to self-induced dehydration. Careful observance of water intake can help to avoid problems. Feeding meals soaked in warm water and/or adding salt to the meal might entice a horse to increase water intake.

Jarvis N. Clinical care of the geriatric horse. In Practice, Jan/Feb (2021) 35-44.

Argo CM. Nutritional Management of the Older Horse. Vet Clin Equine 32 (2016) 343–354.

Dr. Kathleen Crandell earned her MS in Equine Nutrition and Exercise Physiology and PhD in Equine Nutrition and Reproduction from Virginia Polytechnic Institute and State University (Virginia Tech). Dr. Crandell was a Superintendent of the Virginia Tech Middleburg Agricultural Research and Extension Center in Middleburg, Virginia, where she ran an equine research and breeding program with over 100 Thoroughbred horses. For the past 26 years, she has been an equine nutrition consultant for Kentucky Equine Research (KER), responsible for support of the national and international feed mills associated with KER with feed formulation, advising on issues of manufacturing and packaging of equine feeds and customer equine feeding recommendations. She also provides recommendations for nutritional programs of individual horses or farms and equine publications, and has consulted for some of the top equine competitors in the US. Dr. Crandell has presented nutritional seminars for education of the general equine public and scientific community around the world. Dr. Crandell has authored book chapters and articles in refereed journals. She also writes or is interviewed for articles on specific topics in equine nutrition for KER publications, KER.com Equinews website and popular magazines. In addition, Dr. Crandell is an Instructor for Equine Guelph, University of Guelph, Ontario, Canada, teaching an equine nutrition course “Advanced Equine Health through Nutrition”, an in-depth study of nutritional related diseases and disorders. Dr. Crandell has been awarded 3 John H. Daniels Fellowships by the National Sporting Library in Middleburg, Virginia, to study historical perspectives on equine nutrition, supplementation and laminitis. Having previously owned a small breeding farm and competed in endurance and competitive trail, she is currently an avid trail rider with her Arabian and half-Arabian horses.